Siemerling–Creutzfeldt Disease

Patient Tools

Read, save, and share this guide

Use these quick tools to make this medical article easier to read, print, save, or share with a family member.

On this page16 sections

Article Summary

Siemerling–Creutzfeldt disease is an older name for X-linked adrenoleukodystrophy (X-ALD). It is a genetic disease. A change (mutation) in the ABCD1 gene makes the body unable to break down very long-chain fatty acids (VLCFAs). These fatty acids slowly build up in the brain, the spinal cord, and the adrenal glands. Over time, this buildup damages the myelin (the protective covering of nerves) and causes adrenal...

Key Takeaways

  • This article explains Types in simple medical language.
  • This article explains Causes in simple medical language.
  • This article explains Symptoms in simple medical language.
  • This article explains Diagnostic tests in simple medical language.
Before reading

RX Patient Tools

Use these quick guides before reading the article, or return to them when you need help preparing questions for a doctor.

Start here Choose the right pathway for symptoms, reports, medicines, or urgent warning signs. Disease article roadmap Read this topic step by step: meaning, symptoms, warning signs, diagnosis, treatment, prevention, and follow-up. Treatment planner Prepare questions about treatment choices, benefits, risks, side effects, and follow-up. Family & caregiver guide Organize symptoms, reports, medicines, questions, and follow-up safely. Nutrition & diet guide Prepare food, hydration, supplement, and medicine-timing questions safely. Prevention guide Organize risk factors, protective habits, screening, and warning signs. Recovery guide Prepare a safe plan for activity, rehabilitation, warning signs, and follow-up.
Educational health guideWritten for patient understanding and clinical awareness.
Reviewed content workflowUse writer and reviewer profiles for stronger trust.
Emergency safety firstUrgent warning signs are highlighted below.
Choose your reading view

Patient View highlights a simple learning journey. Clinical View reveals structure, evidence, and editorial completeness.

Definition

Siemerling–Creutzfeldt disease is an older name for X-linked adrenoleukodystrophy (X-ALD). It is a disease. A change (mutation) in the ABCD1 gene makes the body unable to break down very long-chain fatty acids (VLCFAs). These fatty acids slowly build up in the brain, the , and the . Over time, this buildup damages the myelin (the protective covering of nerves) and causes failure (Addison’s disease). Because the gene is on the X chromosome, the condition mostly affects boys and men, while women who carry the gene change can also develop symptoms later in life. The disease has different forms and different speeds of , but early detection and are very important because some treatments can slow or halt brain damage if started early. NCBI+1adrenoleukodystrophy.info

Siemerling–Creutzfeldt disease is an old name for a disease we now call X-linked adrenoleukodystrophy (X-ALD). It is a genetic disorder. It mainly harms the white matter of the brain (the myelin that helps nerves send signals) and the adrenal glands on top of the . The problem comes from a change (mutation) in the ABCD1 gene on the X chromosome. This gene makes a protein that moves very-long-chain fatty acids (VLCFAs) into peroxisomes, where the body should break them down. When the transporter fails, these fatty acids build up and damage brain cells, the spinal cord, and the adrenal glands. Some boys develop fast brain and demyelination; some teens or adults develop slow, stiff walking and ; some people show only adrenal failure for years. NCBIMedlinePlus


Other names

Siemerling–Creutzfeldt disease has several other names. The most common modern name is X-linked adrenoleukodystrophy (X-ALD). Older or related names include Addison–Schilder disease and Schilder–, which highlight the mix of adrenal failure (“Addison”) and brain demyelination (“leukodystrophy”). Historical reports by Siemerling and Creutzfeldt in 1923 described boys with darkened skin from adrenal failure and brain disease; the eponym stuck for decades. Today, clinicians prefer “X-ALD” because it points to the X-linked inheritance and the ABCD1 gene defect. Importantly, Schilder’s disease (diffuse ) is not the same as ALD. adrenoleukodystrophy.infoPMCPubMedBrainFacts


Types

X-ALD does not look the same in every person. Here are the main types doctors recognize:

  1. Childhood cerebral ALD. Boys, usually 4–10 years old. Rapid inflammation destroys brain myelin, especially in the back (parieto-occipital) regions. Behavior and school performance worsen first, then vision, hearing, and movement. Without early treatment, decline is fast. Mayo Clinic

  2. Adolescent or adult cerebral ALD. Same brain process as childhood cerebral ALD but starting later. Progression can still be fast once brain inflammation begins. NCBI

  3. Adrenomyeloneuropathy (AMN). Teens or adults. Slow, long-term and weakness of the legs, balance problems, numb feet, or sexual problems, and sometimes thinking changes. This reflects spinal cord and peripheral nerve damage more than active brain inflammation. NCBI

  4. Addison-only (isolated ). Some boys or men first show only adrenal failure for years—, , skin darkening, low blood pressure—before any nerve problems appear. NCBIMayo Clinic

  5. Symptomatic female carriers. Women with an ABCD1 variant can develop AMN-like symptoms in adulthood (often milder and later than in men). NCBI


Causes

Note: in X-ALD, “causes” mainly means the genetic and biological reasons why damage happens or why it gets worse. The core cause is the ABCD1 mutation; the items below explain how that leads to disease and what may influence the course.

  1. ABCD1 gene mutation (primary cause). A change in this X-linked gene disrupts the peroxisomal transporter ALDP, the root problem in ALD. NCBI

  2. X-linked inheritance. Because the gene is on the X chromosome, most severely affected patients are boys/men; women can be symptomatic carriers. NCBI

  3. Peroxisomal import failure. VLCFAs cannot enter peroxisomes for normal breakdown, so they build up in tissues. NCBI

  4. VLCFA accumulation (C24:0, C26:0). These long saturated fats collect in brain white matter, adrenal cortex, and testes, making cells sick. MedlinePlus

  5. Myelin membrane injury. VLCFAs stiffen and destabilize myelin, making it fragile and prone to breakdown.

  6. Oligodendrocyte damage. Cells that make myelin get stressed by VLCFAs and inflammatory molecules and can die.

  7. Microglial activation and inflammation. Microglia become overactive around damaged myelin and release cytokines, which speeds up demyelination.

  8. Oxidative stress. Accumulated fatty acids and inflammation create harmful reactive oxygen species, injuring cells further.

  9. Mitochondrial dysfunction. Energy factories inside cells work poorly under VLCFA stress, weakening neurons and glia.

  10. Adrenal cortex toxicity. VLCFAs damage -making cells, causing adrenal insufficiency (Addison disease). Mayo Clinic

  11. Spinal cord axonopathy (AMN). Long nerve fibers in the spinal cord gradually degenerate, leading to stiff, weak legs.

  12. . Nerve fibers in the legs can be damaged, causing , burning , and loss of reflexes.

  13. Immune triggers of cerebral disease. In some patients, infections or other stresses may trigger the switch from silent VLCFA buildup to active brain inflammation (hypothesized mechanism; not fully predictable).

  14. Hormonal stress. Illness, , or surgery can unmask adrenal failure and cause crisis in people with low cortisol.

  15. Head (possible trigger). Head injury has been reported before cerebral ALD in some cases, though this link is not certain.

  16. Diet is not the primary cause. VLCFAs are made inside the body; diet alone does not cause ALD or normalize VLCFA without other measures. Wikipedia

  17. De novo mutation. A new ABCD1 mutation can appear even when is negative. NCBI

  18. Modifier genes. Other genes may influence who develops brain inflammation versus AMN (active research).

  19. Age and sex. Being male and being in childhood increases the risk for the rapid cerebral form; adults more often have AMN. NCBI

  20. Time without . Delayed recognition allows silent damage to progress, especially adrenal failure and early brain changes.


Symptoms

  1. Behavior and school decline. A child may become irritable, lose attention, or fall behind in class—often the first sign of cerebral ALD. Mayo Clinic

  2. Vision loss. Trouble seeing, , or loss of visual fields as the back of the brain is affected. AJNR

  3. Hearing problems. Difficulty understanding speech or hearing loss can appear as white matter pathways are damaged.

  4. Seizures. Electrical storms in injured brain tissue can cause convulsions or staring spells.

  5. Headaches and . Can occur with cerebral inflammation or raised pressure.

  6. Walking stiffness (spasticity). Tight muscles and scissoring gait are common in AMN and later cerebral disease.

  7. Leg weakness and fatigue. Climbing stairs and long walks become hard; legs tire quickly.

  8. Balance and coordination trouble. Falls, clumsiness, and trouble with fine motor tasks.

  9. Numb or burning feet. Peripheral nerves can be damaged, causing sensory changes and pain.

  10. Bladder or bowel issues. Urgency, incontinence, or constipation from spinal cord involvement.

  11. Sexual dysfunction. Erectile problems or reduced libido in adult men due to cord and hormonal issues.

  12. Skin darkening (hyperpigmentation). A classic sign of low adrenal hormones (high ACTH). Mayo Clinic

  13. Low blood pressure and dizziness. Especially when standing (orthostatic hypotension) in adrenal failure.

  14. Weight loss, nausea, salt craving. Common features of Addison disease in ALD. Mayo Clinic

  15. Adrenal crisis. Severe vomiting, abdominal pain, very low blood pressure, and shock during stress or illness if cortisol is very low (medical emergency).


Diagnostic tests

A) Physical examination (bedside observations)

  1. General and skin exam. Doctors look for skin darkening, weight loss, dehydration, or signs of chronic illness—clues to adrenal failure. Mayo Clinic

  2. Neurological exam. Checks strength, tone, reflexes (often brisk in legs), sensation, coordination, and cranial nerves to map what parts of the nervous system are involved.

  3. Gait assessment. Watching how the person walks (spastic, scissoring, wide-based) helps identify AMN or advanced cerebral disease.

  4. Orthostatic vitals. Blood pressure and pulse measured lying and standing can show adrenal-related low blood pressure.

  5. Visual fields and eye movements. Quick bedside checks can uncover parieto-occipital damage that affects vision in cerebral ALD.

B) Manual / simple office tests

  1. Mini-Mental or other cognitive screen. Short memory and attention tests detect early thinking changes in cerebral disease.

  2. Romberg and tandem gait. Standing with eyes closed and heel-to-toe walking detect balance and position-sense problems.

  3. Bedside visual field confrontation. Patient counts fingers in each quadrant; loss suggests occipital pathway injury.

  4. Color vision plates (Ishihara). Simple check for visual pathway dysfunction; can be abnormal in posterior white matter disease.

C) Laboratory and pathological tests

  1. Plasma very-long-chain fatty acids (VLCFA). Elevated C26:0 and high ratios (C24:0/C22:0; C26:0/C22:0) are a key biochemical hallmark in males with ALD. MedlinePlus

  2. Newborn screening (C26:0-lysophosphatidylcholine). Many regions now screen dried blood spots for C26:0-LPC, which catches ALD early so care can start before symptoms. PMCTexas Health ServicesPubMed

  3. ABCD1 genetic testing. DNA sequencing (and deletion/duplication analysis) confirms the diagnosis, identifies the family mutation, and supports carrier testing. NCBI

  4. ACTH stimulation test. Measures how the adrenal glands respond; poor cortisol rise confirms adrenal insufficiency. Mayo Clinic

  5. Morning cortisol and plasma ACTH. Low cortisol with high ACTH strongly suggests primary adrenal failure, common in ALD. Mayo Clinic

  6. Peroxisomal function in fibroblasts (specialized). Skin-cell studies can show defective VLCFA metabolism when the blood tests are inconclusive (rarely needed today). PubMedWiley Online Library

D) Electrodiagnostic tests

  1. Nerve conduction studies (NCS). Detect peripheral neuropathy in AMN—reduced speeds or amplitudes, especially in legs.

  2. Visual evoked potentials (VEP). Measure brain responses to visual patterns; delays reflect demyelination of optic pathways in cerebral forms.

  3. Somatosensory or brainstem auditory evoked potentials (SSEP/BAEP). Show slowed conduction in sensory or auditory brain pathways, supporting white matter damage.

  4. Electroencephalogram (EEG). Looks for epileptic activity in patients with seizures and can reflect diffuse brain dysfunction.

E) Imaging tests

  1. Brain MRI with contrast and Loes scoring. MRI typically shows symmetric parieto-occipital white-matter lesions with a ring of contrast enhancement at the active edge in cerebral ALD. The Loes score grades how much of the brain is involved (0–34) and helps track severity and timing of possible interventions. Spinal MRI may show cord atrophy in AMN. AJNRPMCThieme

Non-pharmacological treatments

A) Physiotherapy

  1. Gait and posture training
    Description: A physical therapist teaches safe walking patterns, posture correction, and step practice using visual cues and metronome pacing. Assistive devices (cane, walker) are fitted if needed. Training may use treadmill with harness for safety. Purpose: reduce falls, improve walking efficiency. Mechanism: repetitive practice strengthens remaining neural pathways and muscles; external cues compensate for motor planning deficits. Benefits: steadier gait, fewer stumbles, better endurance, more confidence.

  2. Spasticity stretching program
    Description: Daily gentle stretches for calves, hamstrings, hip flexors, and adductors with hold–relax methods; splints or night ankle-foot orthoses may be used. Purpose: reduce muscle tightness and contractures. Mechanism: lengthens muscle–tendon units and modulates stretch reflex excitability. Benefits: easier movement, less pain, improved sleep, better positioning for sitting and walking.

  3. Strengthening of antigravity muscles
    Description: Progressive resistance exercises for glutes, quadriceps, core, and back extensors using bands, bodyweight, or machines, avoiding over-fatigue. Purpose: maintain function. Mechanism: hypertrophy and improved motor unit recruitment. Benefits: stronger transfers, better stair climbing, slower decline.

  4. Balance and vestibular therapy
    Description: Practice tandem stance, single-leg support (with aid), dynamic reaching, and compliant-surface work. Purpose: reduce falls. Mechanism: challenges visual, vestibular, and proprioceptive systems to recalibrate postural responses. Benefits: improved stability indoors/outdoors.

  5. Task-specific functional training
    Description: Rehearse daily tasks—sit-to-stand, bed mobility, dressing—using graded cues and energy-saving methods. Purpose: keep independence. Mechanism: motor learning through context-specific repetition. Benefits: faster ADLs, less caregiver burden.

  6. Aquatic therapy
    Description: Water supports body weight, reduces joint load, and allows safe practice of gait, kicks, and trunk rotations. Purpose: improve mobility with low impact. Mechanism: buoyancy and resistance of water build strength and range. Benefits: better flexibility, mood boost, pain relief.

  7. Orthotic management (AFOs, insoles)
    Description: Custom ankle-foot orthoses keep ankle at neutral and control knee hyperextension; insoles improve foot alignment. Purpose: stabilize gait. Mechanism: mechanical alignment reduces energy cost and toe drag. Benefits: safer, faster walking.

  8. Serial casting for contracture prevention
    Description: Short-term calf casts progressively stretch tight muscles. Purpose: regain ankle dorsiflexion. Mechanism: prolonged low-load stretch remodels tissue. Benefits: improved foot clearance, easier brace fitting.

  9. Respiratory physiotherapy
    Description: Breathing exercises, incentive spirometry, and cough-assist training if weakness advances. Purpose: maintain ventilation and cough strength. Mechanism: improves chest wall mobility and inspiratory/expiratory muscle function. Benefits: fewer infections, better stamina.

  10. Functional electrical stimulation (FES)
    Description: Timed stimulation (e.g., peroneal nerve) to lift the foot during swing phase. Purpose: reduce foot drop. Mechanism: external current activates muscles in sync with gait. Benefits: fewer trips, more natural gait.

  11. Pain and spasm self-management
    Description: Heat, gentle massage, positioning cushions, and pacing strategies. Purpose: reduce discomfort without extra pills. Mechanism: modulates muscle tone and local circulation. Benefits: better sleep and activity tolerance.

  12. Wheelchair and seating optimization
    Description: Proper seat width, back support, and cushions to prevent pressure sores; power mobility when needed. Purpose: safe mobility when walking is unsafe. Mechanism: pressure distribution and posture support. Benefits: comfort, independence, skin protection.

  13. Falls-prevention home program
    Description: Remove trip hazards, add grab bars, improve lighting, use non-slip footwear. Purpose: cut injury risk. Mechanism: environmental control reduces exposure to hazards. Benefits: fewer ER visits, peace of mind.

  14. Bladder and bowel training
    Description: Timed voiding, pelvic-floor cues, fiber and fluid planning, and constipation prevention strategies. Purpose: manage neurogenic symptoms. Mechanism: habit scheduling and pelvic muscle control. Benefits: fewer accidents, more comfort.

  15. Energy conservation & fatigue management
    Description: Plan the day, alternate heavy/light tasks, sit when possible, use labor-saving tools. Purpose: reduce exhaustion. Mechanism: pacing prevents over-fatigue of weakened pathways. Benefits: more activities completed, better quality of life.

B) Mind-body, “gene-aware,” and educational therapies

  1. Condition education for family
    Description: Teach what ALD is, signs of adrenal crisis, and when to seek help. Purpose: early action. Mechanism: informed caregivers spot problems sooner. Benefits: safer care, less fear. NCBI

  2. Adrenal crisis action plan
    Description: Written plan with stress-dose steroids, emergency injection, and when to call an ambulance. Purpose: prevent life-threatening crises. Mechanism: swift cortisol replacement during illness/injury. Benefits: reduced hospitalizations. NCBI

  3. MRI and neuropsychology surveillance pathway
    Description: Scheduled MRIs and cognitive testing to catch early cerebral changes. Purpose: treat early. Mechanism: monitoring enables timely HSCT/gene therapy evaluation. Benefits: better outcomes. NCBI

  4. Genetic counseling
    Description: Explain inheritance, test relatives, discuss family planning options. Purpose: informed decisions. Mechanism: identifies carriers; supports prenatal or preimplantation choices. Benefits: reduces unexpected cases. PubMed

  5. School-based support plan (IEP/504)
    Description: Classroom accommodations for attention, processing speed, and mobility, plus therapy services. Purpose: protect learning. Mechanism: tailored supports bridge gaps. Benefits: better school success.

  6. Cognitive rehabilitation
    Description: Attention and memory strategies, visual–spatial training, and task-chunking. Purpose: maintain skills. Mechanism: neuroplasticity and compensatory tools. Benefits: improved daily functioning.

  7. Psychological counseling (family-centered)
    Description: Coping skills for stress, grief, and uncertainty; sibling support. Purpose: mental health. Mechanism: CBT and supportive therapy. Benefits: less anxiety/depression.

  8. Mind–body practices (breathing, relaxation, mindfulness)
    Description: Short, daily routines for breath control, guided imagery, or mindfulness apps. Purpose: reduce stress and pain perception. Mechanism: lowers autonomic arousal and muscle tension. Benefits: better sleep, mood, and adherence.

  9. Speech-language and swallowing therapy
    Description: Language/communication support and swallow safety training; texture modification as needed. Purpose: prevent aspiration, support expression. Mechanism: targeted muscle and strategy training. Benefits: safer eating, better communication.

  10. Nutrition coaching aligned with adrenal care
    Description: Regular meals, adequate salt (if advised), hydration plans, sick-day rules, and medication–food timing. Purpose: support steroid therapy and energy. Mechanism: stabilizes blood pressure and glucose during illness. Benefits: fewer crises, steadier energy. NCBI


Drug treatments

Notes: Drug therapy does not cure ALD. Medicines treat adrenal failure and symptoms (spasticity, seizures, pain, mood). Disease-modifying options are HSCT and gene therapy for selected patients (covered earlier). Always individualize with a specialist.

  1. Hydrocortisone (oral; steroid replacement)
    Class: Glucocorticoid. Dosage/time: Typically divided 2–3 times daily; stress-doses during illness (doctor sets exact dose). Purpose: replace missing cortisol. Mechanism: restores physiologic glucocorticoid action. Side effects: weight gain, mood change, high blood sugar, bone loss with long-term high doses. NCBI

  2. Fludrocortisone (oral; mineralocorticoid)
    Class: Mineralocorticoid. Dosage: once daily (dose individualized). Purpose: maintain blood pressure and salt balance. Mechanism: acts like aldosterone to retain sodium and water. Side effects: fluid retention, high blood pressure, low potassium. NCBI

  3. Intramuscular hydrocortisone emergency injection
    Class: Glucocorticoid (rescue). Use/time: Give during vomiting, severe illness, or trauma when oral intake is not possible—per emergency plan. Purpose: prevent adrenal crisis. Mechanism: rapid systemic cortisol. Side effects: same class effects; emergency benefits outweigh risks. NCBI

  4. Baclofen
    Class: Antispasticity (GABA-B agonist). Dosage: oral, titrated slowly; intrathecal pump for severe cases. Purpose: reduce spasticity. Mechanism: decreases excitatory neurotransmission in spinal cord. Side effects: drowsiness, weakness; abrupt stop can cause withdrawal.

  5. Tizanidine
    Class: α2-adrenergic agonist. Dosage: divided doses; titrate. Purpose: relieve muscle tone/spasms. Mechanism: reduces polysynaptic spinal reflex activity. Side effects: dry mouth, low blood pressure, liver enzyme elevation (monitor).

  6. Diazepam (night spasm relief)
    Class: Benzodiazepine. Dosage: bedtime or as needed. Purpose: reduce nocturnal spasms and anxiety. Mechanism: enhances GABA-A activity. Side effects: sedation, dependence risk.

  7. Levetiracetam
    Class: Antiseizure. Dosage: weight-based, usually twice daily. Purpose: control seizures. Mechanism: binds SV2A to modulate neurotransmitter release. Side effects: mood changes, somnolence.

  8. Valproate
    Class: Antiseizure/mood stabilizer. Dosage: individualized; monitor levels. Purpose: seizure control if levetiracetam not enough. Mechanism: ↑ GABA and sodium channel effects. Side effects: liver toxicity, weight gain, teratogenicity (avoid in pregnancy).

  9. Gabapentin / Pregabalin
    Class: Neuropathic pain modulators. Dosage: titrate. Purpose: relieve burning/tingling pain. Mechanism: α2δ subunit modulation reduces excitatory release. Side effects: dizziness, edema.

  10. NSAIDs (e.g., ibuprofen) or acetaminophen
    Class: Analgesic/antipyretic. Purpose: headache, musculoskeletal pain. Mechanism: COX inhibition (NSAIDs) or central analgesia (acetaminophen). Side effects: stomach irritation (NSAIDs), liver risk (acetaminophen at high doses).

  11. Selective antispasmodic injections (botulinum toxin)
    Class: Neurotoxin, local injection. Purpose: focal spasticity (adductors, calves). Mechanism: blocks acetylcholine release at neuromuscular junction. Side effects: local weakness; temporary.

  12. Methylphenidate (specialist use)
    Class: Stimulant. Purpose: attention deficits/processing speed in selected cases. Mechanism: ↑ dopamine/norepinephrine in the synapse. Side effects: appetite loss, insomnia; monitor heart rate.

  13. Antidepressants (e.g., SSRIs)
    Class: Serotonergic antidepressants. Purpose: depression/anxiety. Mechanism: serotonin reuptake inhibition. Side effects: nausea, sexual dysfunction, agitation early on.

  14. Anticholinergics or mirabegron
    Class: Bladder agents. Purpose: urgency/incontinence. Mechanism: detrusor relaxation. Side effects: dry mouth/constipation (anticholinergics); BP changes (mirabegron).

  15. Sialorrhea treatments (glycopyrrolate or botulinum toxin to salivary glands)
    Class: Anticholinergic (systemic) or local neurotoxin. Purpose: drooling control. Mechanism: reduces salivary secretion or gland output. Side effects: dry mouth, thickened secretions (systemic).

(For disease-modifying options—HSCT and gene therapy—see “Regenerative/Stem-cell” section below.)


Dietary “molecular” supports

Important: Diet cannot cure ALD. Restricting VLCFAs alone is not effective as a standalone treatment. Some options may help general health or be used alongside medical care. Evidence quality varies; always discuss with your specialist.

  1. Lorenzo’s oil (oleic + erucic acids)
    Dose/Use: Specialist-directed; careful monitoring needed. Function/mechanism: Lowers plasma VLCFA levels by competitive inhibition of elongation. Evidence: Can reduce VLCFAs; clinical benefit uncertain, especially after symptoms start; not FDA-approved. Note: Monitor liver enzymes and platelets. New England Journal of MedicineVerywell Health

  2. Balanced, regular meals with adequate salt (if adrenal insufficiency and doctor advises)
    Dose: Diet plan from dietitian. Function: Supports blood pressure and energy; helps during illness (“sick-day rules”). Mechanism: Sodium and fluids support mineralocorticoid therapy. NCBI

  3. Omega-3 (DHA/EPA) foods or supplements (guarded use)
    Function: General anti-inflammatory and membrane support; evidence in ALD is limited. Mechanism: Incorporation into neuronal membranes may modulate inflammation. Note: Discuss dose and interactions with your clinician.

  4. Vitamin D and calcium (bone health with chronic steroids)
    Function: Protect bone density. Mechanism: Supports calcium absorption and bone remodeling; important if on long-term glucocorticoids. Note: Monitor levels.

  5. Vitamin E (antioxidant) – cautious use
    Function: General oxidative stress support; specific ALD benefit unproven. Mechanism: Free-radical scavenging in lipid membranes.

  6. Coenzyme Q10 (mitochondrial cofactor) – limited evidence
    Function: General energy metabolism support. Mechanism: Electron transport chain cofactor; theoretical neuroprotective role.

  7. Alpha-lipoic acid – limited evidence
    Function: Antioxidant and glucose metabolism cofactor. Mechanism: Regenerates other antioxidants; theoretical support for nerve health.

  8. Magnesium (cramp support if low)
    Function: Muscle relaxation and nerve function. Mechanism: NMDA modulation; supports neuromuscular transmission.

  9. High-fiber nutrition and hydration
    Function: Bowel regularity in neurogenic bowel. Mechanism: Improves stool consistency and transit.

  10. Illness “sick-day” nutrition plan
    Function: Prevents adrenal crisis (fluids, salt, easily digestible carbs); coordinate with stress-dose steroids. Mechanism: Supports hemodynamics during physiological stress. NCBI


Immunity-booster / regenerative / stem-cell” options

  1. Allogeneic hematopoietic stem-cell transplant (HSCT)
    What it is: Transplant of donor stem cells after conditioning chemotherapy. Dose/Process: Complex hospital procedure; detailed protocols vary by center. Function/Mechanism: Replaces microglia-precursor cells; donor-derived cells populate the brain and halt inflammatory demyelination when done early in cerebral ALD. Evidence: Strong for early cCALD; not helpful in advanced disease. Risks: Graft-versus-host disease, infections, graft failure, treatment-related mortality—performed only at expert centers. PMC+1PubMed

  2. Gene therapy: elivaldogene autotemcel (SKYSONA)
    What it is: Autologous stem cells are taken from the patient, corrected ex vivo with a lentiviral vector carrying a functional ABCD1, then reinfused after conditioning. Function/Mechanism: Corrected cells aim to repopulate brain microglia-like cells and reduce neuroinflammation. Evidence: Approved for certain boys with early, active cALD; new FDA safety labeling warns of increased risk of blood cancers (MDS/AML); use requires careful risk–benefit discussion. U.S. Food and Drug Administration+1

  3. Intrathecal baclofen pump (device-assisted therapy)
    What it is: A programmable pump delivers baclofen into the spinal fluid. Function: Strong, targeted spasticity control when oral meds fail. Mechanism: Direct GABA-B agonism in the spinal cord. Note: Surgical implant; requires long-term follow-up.

  4. Botulinum toxin for focal spasticity (localized “regenerative-adjacent” comfort)
    Function: Reduces overactive muscles to allow better therapy and brace use. Mechanism: Temporarily blocks acetylcholine release; helps prevent contractures so other rehab can work.

  5. Orthopedic procedures for contractures
    Function: Tendon lengthening or release to improve limb position. Mechanism: Restores joint range to support mobility aids and hygiene.

  6. Clinical trials (future cell or gene-editing approaches)
    Function: Access to investigational therapies. Mechanism: Varies; may target peroxisomal function or inflammation. Note: Discuss eligibility with a specialist center; risks and benefits are uncertain.


Surgeries or procedures

  1. HSCT – see above: done to halt early cerebral disease.

  2. Intrathecal baclofen pump implantationto control severe spasticity when tablets fail.

  3. Gastrostomy tube placementto maintain nutrition and medication delivery when swallowing is unsafe.

  4. Orthopedic tendon lengtheningto treat fixed contractures that limit walking, sitting, or hygiene.

  5. Botulinum toxin injections (procedural)to relax focal spastic muscles and ease bracing/therapy.


Prevention & safety tips

  1. Genetic counseling and family testing to identify at-risk relatives early. PubMed

  2. Newborn screening / early biochemical testing where available. ARUP Consult

  3. Regular MRI and neuropsychology surveillance for boys with ALD gene changes. NCBI

  4. Adrenal monitoring (cortisol, ACTH) and lifelong steroid replacement if needed. NCBI

  5. Written adrenal crisis plan and emergency steroid kit. NCBI

  6. Vaccinations per schedule to reduce infection stress.

  7. Fall-proof home and safe mobility aids to prevent injuries.

  8. Pressure-injury prevention (cushions, repositioning) if mobility is limited.

  9. Oral and swallow checks to avoid aspiration.

  10. Early referral to experienced ALD/HSCT centers when MRI changes appear. PMC


When to see a doctor (red flags)

  • Fever, vomiting, severe illness, trauma, or surgery in anyone with known adrenal insufficiency (needs stress-dose steroids).

  • New behavior changes, learning loss, vision/hearing decline, or seizures in a child with ALD risk.

  • Worsening balance, walking, bladder/bowel control, or new falls.

  • Fainting, severe fatigue, salt craving, darkening of skin, low blood pressure.

  • Any MRI report showing new white-matter changes in a known carrier.


What to eat and what to avoid

  • Eat: Balanced meals with lean protein, whole grains, fruits/vegetables, and adequate fluids. If your doctor advises, include adequate salt to support mineralocorticoid therapy. Plan sick-day foods (simple carbohydrates, soups, oral rehydration) when unwell.

  • Avoid: Skipping steroid doses; dehydration; very low-salt fad diets if you need mineralocorticoid; unproven supplements that promise cures; alcohol excess that worsens balance; interactions your doctor warns about.

  • Remember: Diet supports overall health and adrenal care, but it does not replace HSCT/gene-therapy decisions for early cerebral disease. NCBI

Frequently asked questions (FAQ)

  1. Is Siemerling–Creutzfeldt disease the same as ALD?
    Yes. It is an older name for X-linked adrenoleukodystrophy (X-ALD). NCBI

  2. What causes it?
    A change in the ABCD1 gene leads to buildup of very long-chain fatty acids that harm myelin and adrenal glands. ARUP Consult

  3. How is it diagnosed?
    By VLCFA blood testing, ABCD1 genetic testing, and brain MRI, plus adrenal hormone tests. ARUP ConsultNCBI

  4. What forms exist?
    Childhood cerebral ALD, adrenomyeloneuropathy (AMN), and Addison-only; women carriers may have symptoms later. NCBI

  5. Can medicine cure it?
    No drug cures ALD. Care focuses on adrenal replacement, symptom control, and early HSCT/gene therapy in selected patients. PMCU.S. Food and Drug Administration

  6. Does HSCT really help?
    Yes, when done early in cerebral ALD, HSCT can halt progression, but it has serious risks and must be done at expert centers. PMC+1

  7. What about gene therapy?
    Elivaldogene autotemcel (SKYSONA) is approved for certain boys with early, active cALD, but the FDA now warns of increased blood-cancer risk after treatment; decisions require careful specialist discussion. U.S. Food and Drug Administration+1

  8. Is Lorenzo’s oil a cure?
    No. It can lower VLCFAs, but trials show uncertain clinical benefit, especially once symptoms begin; it is not FDA-approved. New England Journal of MedicineVerywell Health

  9. How often should MRI be done?
    Specialists follow regular MRI schedules in at-risk boys to detect early brain changes; timing depends on age and prior results. NCBI

  10. What is the life expectancy?
    It varies widely by form and timing of treatment. Early detection and timely HSCT in cerebral disease improve outcomes compared with no treatment. PMC

  11. Can girls/women be affected?
    Yes. Many female carriers develop walking stiffness and sensory symptoms in adulthood; adrenal failure is less common. NCBI

  12. Is newborn screening available?
    Many regions now screen for ALD using C26:0-lysophosphatidylcholine; ask your local program. ARUP Consult

  13. How is adrenal insufficiency managed day-to-day?
    With hydrocortisone (and often fludrocortisone), a sick-day plan, and an emergency steroid injection kit. NCBI

  14. What specialists should be involved?
    Neurology, endocrinology, transplant/gene therapy centers, genetics, rehabilitation, dietetics, and mental health.

  15. What can families do now?
    Learn the signs of adrenal crisis, keep appointments for MRI and labs, follow therapy programs, make the home safe, and link with an ALD expert center.

Disclaimer: Each person’s journey is unique, treatment planlife stylefood habithormonal conditionimmune systemchronic disease condition, geological location, weather and previous medical  history is also unique. So always seek the best advice from a qualified medical professional or health care provider before trying any treatments to ensure to find out the best plan for you. This guide is for general information and educational purposes only. Regular check-ups and awareness can help to manage and prevent complications associated with these diseases conditions. If you or someone are suffering from this disease condition bookmark this website or share with someone who might find it useful! Boost your knowledge and stay ahead in your health journey. We always try to ensure that the content is regularly updated to reflect the latest medical research and treatment options. Thank you for giving your valuable time to read the article.

The article is written by Team RxHarun and reviewed by the Rx Editorial Board Members

Last Updated: September 09, 2025.

  1. Rare Diseases and Medical Genetics.[rxharun.com]
  2. i2023_IFPMA_Rare_Diseases_Brochure_28Feb2017_FINAL.[rxharun.com]
  3. the-UK-rare-diseases-framework.[rxharun.com]
  4. National-Recommendations-for-Rare-Disease-Health-Care-Summary.[rxharun.com]
  5. History of rare diseases and their genetic.[rxharun.com]
  6. health-care-and-rare-disorders.[rxharun.com]
  7. Rare Disease Registries.[rxharun.com]
  8. autoimmune-Rare-Genetic-Diseases.[rxharun.com]
  9. Rare Genetic Diseases.[rxharun.com]
  10. rare-disease-day.[rxharun.com]
  11. Rare_Disease_Drugs_e.[rxharun.com]
  12. fda-CDER-Rare-Diseases-Public-Workshop-Master.[rxharun.com]
  13. rare-and-inherited-disease-eligibility-criteria.[rxharun.com]
  14. FDA-rare-disease-list.pdf-rxharun.com1 Human-Gene-Therapy-for-Rare Diseases_Jan_2020fda.[rxharun.com]
  15. FDA-rare-disease-lists.[rxharun.com]
  16. 30212783fnl_Rare Disease.[rxharun.com]
  17. FDA-rare-disease-list.[rxharun.com]
  18. List of rare disease.[rxharun.com]
  19. Genome Res.-2025-Steyaert-755-68.[rxharun.com]
  20. uk-practice-guidelines-for-variant-classification-v4-01-2020.[rxharun.com]
  21. PIIS2949774424010355.[rxharun.com]
  22. hidden-costs-2016.[rxharun.com]
  23. B156_CONF2-en.[rxharun.com]
  24. IRDiRC_State-of-Play-2018_Final.[rxharun.com]
  25. IRDR_2022Vol11No3_pp96_160.[rxharun.com]
  26. from-orphan-to-opportunity-mastering-rare-disease-launch-excellence.[rxharun.com]
  27. Rare disease fda.[rxharun.com]
  28. England-Rare-Diseases-Action-Plan-2022.[rxharun.com]
  29. SCRDAC 2024 Report.[rxharun.com]
  30. CORD-Rare-Disease-Survey_Full-Report_Feb-2870-2.[rxharun.com]
  31. Stats-behind-the-stories-Genetic-Alliance-UK-2024.[rxharun.com]
  32. rare-and-inherited-disease-eligibility-criteria-v2.[rxharun.com]
  33. ENG_White paper_A4_Digital_FINAL.[rxharun.com]
  34. UK_Strategy_for_Rare_Diseases.[rxharun.com]
  35. MalaysiaRareDiseaseList.[rxharun.com]
  36. EURORDISCARE_FULLBOOKr.[rxharun.com]
  37. EMHJ_1999_5_6_1104_1113.[rxharun.com]
  38. national-genomic-test-directory-rare-and-inherited-disease-eligibilitycriteria-.[rxharun.com]
  39. be-counted-052722-WEB.[rxharun.com]
  40. RDI-Resource-Map-AMR_MARCH-2024.[rxharun.com]
  41. genomic-analysis-of-rare-disease-brochure.[rxharun.com]
  42. List-of-rare-diseases.[rxharun.com]
  43. RDI-Resource-Map-AFROEMRO_APRIL[rxharun.com]
  44. rdnumbers.[rxharun.com] .
  45. Rare disease atoz .[rxharun.com]
  46. EmanPublisher_12_5830biosciences-.[rxharun.com]

  1. https://www.ncbi.nlm.nih.gov/books/NBK208609/
  2. https://pmc.ncbi.nlm.nih.gov/articles/PMC6279436/
  3. https://rarediseases.org/rare-diseases/
  4. https://rarediseases.info.nih.gov/diseases
  5. https://en.wikipedia.org/w/index.php?title=Category:Rare_diseases
  6. https://en.wikipedia.org/wiki/List_of_genetic_disorders
  7. https://en.wikipedia.org/wiki/Category:Genetic_diseases_and_disorders
  8. https://medlineplus.gov/genetics/condition/
  9. https://geneticalliance.org.uk/support-and-information/a-z-of-genetic-and-rare-conditions/
  10. https://www.fda.gov/patients/rare-diseases-fda
  11. https://www.fda.gov/science-research/clinical-trials-and-human-subject-protection/support-clinical-trials-advancing-rare-disease-therapeutics-start-pilot-program
  12. https://accp1.onlinelibrary.wiley.com/doi/full/10.1002/jcph.2134
  13. https://www.mayoclinicproceedings.org/article/S0025-6196%2823%2900116-7/fulltext
  14. https://www.ncbi.nlm.nih.gov/mesh?
  15. https://www.rarediseasesinternational.org/working-with-the-who/
  16. https://ojrd.biomedcentral.com/articles/10.1186/s13023-024-03322-7
  17. https://www.rarediseasesnetwork.org/
  18. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/rare-disease
  19. https://www.raregenomics.org/rare-disease-list
  20. https://www.astrazeneca.com/our-therapy-areas/rare-disease.html
  21. https://bioresource.nihr.ac.uk/rare
  22. https://www.roche.com/solutions/focus-areas/neuroscience/rare-diseases
  23. https://geneticalliance.org.uk/support-and-information/a-z-of-genetic-and-rare-conditions/
  24. https://www.genomicsengland.co.uk/genomic-medicine/understanding-genomics/rare-disease-genomics
  25. https://www.oxfordhealth.nhs.uk/cit/resources/genetic-rare-disorders/
  26. https://genomemedicine.biomedcentral.com/articles/10.1186/s13073-022-01026
  27. https://wikicure.fandom.com/wiki/Rare_Diseases
  28. https://www.wikidoc.org/index.php/List_of_genetic_disorders
  29. https://www.medschool.umaryland.edu/btbank/investigators/list-of-disorders/
  30. https://www.orpha.net/en/disease/list
  31. https://www.genetics.edu.au/SitePages/A-Z-genetic-conditions.aspx
  32. https://ojrd.biomedcentral.com/
  33. https://health.ec.europa.eu/rare-diseases-and-european-reference-networks/rare-diseases_en
  34. https://bioportal.bioontology.org/ontologies/ORDO
  35. https://www.orpha.net/en/disease/list
  36. https://www.fda.gov/industry/medical-products-rare-diseases-and-conditions
  37. https://www.gao.gov/products/gao-25-106774
  38. https://www.gene.com/partners/what-we-are-looking-for/rare-diseases
  39. https://www.genome.gov/For-Patients-and-Families/Genetic-Disorders
  40. https://geneticalliance.org.uk/support-and-information/a-z-of-genetic-and-rare-conditions/
  41. https://my.clevelandclinic.org/health/diseases/21751-genetic-disorders
  42. https://globalgenes.org/rare-disease-facts/
  43. https://www.nidcd.nih.gov/directory/national-organization-rare-disorders-nord
  44. https://byjus.com/biology/genetic-disorders/
  45. https://www.cdc.gov/genomics-and-health/about/genetic-disorders.html
  46. https://www.genomicseducation.hee.nhs.uk/doc-type/genetic-conditions/
  47. https://www.thegenehome.com/basics-of-genetics/disease-examples
  48. https://www.oxfordhealth.nhs.uk/cit/resources/genetic-rare-disorders/
  49. https://www.pfizerclinicaltrials.com/our-research/rare-diseases
  50. https://clinicaltrials.gov/ct2/results?recrs
  51. https://apps.who.int/gb/ebwha/pdf_files/EB116/B116_3-en.pdf
  52. https://stemcellsjournals.onlinelibrary.wiley.com/doi/10.1002/sctm.21-0239
  53. https://www.nibib.nih.gov/
  54. https://www.nei.nih.gov/
  55. https://oxfordtreatment.com/
  56. https://www.nidcd.nih.gov/health/https://consumer.ftc.gov/articles/
  57. https://www.nccih.nih.gov/health
  58. https://catalog.ninds.nih.gov/
  59. https://www.aarda.org/diseaselist/
  60. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets
  61. https://www.nibib.nih.gov/
  62. https://www.nia.nih.gov/health/topics
  63. https://www.nichd.nih.gov/
  64. https://www.nimh.nih.gov/health/topics
  65. https://www.nichd.nih.gov/
  66. https://www.niehs.nih.gov/
  67. https://www.nimhd.nih.gov/
  68. https://www.nhlbi.nih.gov/health-topics
  69. https://obssr.od.nih.gov/.
  70. https://www.nichd.nih.gov/health/topics
  71. https://rarediseases.info.nih.gov/diseases
  72. https://beta.rarediseases.info.nih.gov/diseases
  73. https://orwh.od.nih.gov/

RX Clinical Pathway Engine

Continue through a complete learning pathway

Move from understanding the topic to symptoms, tests, treatment, medicines, monitoring, and prevention.

Search the complete library
  1. Understand the condition Begin with the essential facts and a clear explanation of the topic.
  2. Recognize symptoms Learn common symptoms, signs, and patterns of presentation.
  3. Know when to seek help Review urgent warning signs and when professional assessment may be needed.
  4. Understand causes and risks Explore causes, risk factors, mechanisms, and contributing conditions.
  5. Explore tests and diagnosis Learn how clinicians assess the condition and which investigations may be discussed.
  6. Learn treatment approaches Review general treatment categories and management principles.
  7. Understand medicines safely Continue to medicine education, uses, precautions, and monitoring.
  8. Plan monitoring and follow-up Understand monitoring, complications, rehabilitation, and follow-up learning.
  9. Review prevention and self-care Explore prevention, healthy routines, and questions to discuss with a clinician.

Conditions & Diseases

Background, symptoms, causes, diagnosis, and care.

Explore this library

Tests & Investigations

Laboratory, imaging, screening, and diagnostic education.

Explore this library

Medicines

Uses, safety, monitoring, and related medicine knowledge.

Explore this library

Cancer Knowledge

Cancer types, screening, oncology, and treatment education.

Explore this library
Doctor visit helper

Prepare before seeing a doctor

A simple rural-patient checklist to help you explain symptoms clearly, ask better questions, and avoid unsafe self-treatment.

Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

  • Write when the problem started and how it changed.
  • Bring old prescriptions, investigation reports, and current medicines.
  • Write allergies, pregnancy status, diabetes, kidney/liver disease, and major past illnesses.
  • Bring one family member if the patient is weak, elderly, confused, or a child.

Questions to ask

  • What is the most likely cause of my symptoms?
  • Which danger signs mean I should go to hospital quickly?
  • Which tests are necessary now, and which can wait?
  • How should I take medicines safely and what side effects should I watch for?
  • When should I come for follow-up?

Tests to discuss

  • Vital signs: temperature, pulse, blood pressure, oxygen saturation
  • Basic physical examination by a clinician
  • CBC, urine test, blood sugar, or imaging only when clinically needed

Avoid these mistakes

  • Do not use antibiotics, steroid tablets/injections, or strong painkillers without proper medical advice.
  • Do not hide pregnancy, kidney disease, ulcer, allergy, or blood thinner use.
  • Do not delay emergency care when danger signs are present.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

  • Avoid heavy lifting, sudden bending, and prolonged bed rest.
  • Use comfortable posture and gentle movement as tolerated.
  • Discuss physiotherapy, X-ray, or MRI only when clinically needed.

OTC medicine safety

  • For mild back pain, pain-relief medicine may be discussed with a doctor or pharmacist.
  • Avoid repeated painkiller use if you have kidney disease, stomach ulcer, uncontrolled blood pressure, or are taking blood thinners.

Avoid these mistakes

  • Do not start antibiotics without a proper medical decision.
  • Do not use steroid tablets or injections casually for quick relief.
  • Do not delay emergency care because of home remedies.

Get urgent help if

  • Back pain with leg weakness, numbness around private area, loss of urine/stool control, fever, cancer history, or major injury needs urgent care.
Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

Patient health record and symptom diary

Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Medicine doctor / pediatrician for children / qualified clinician
Tests to discuss with doctor
  • Temperature chart and hydration assessment
  • CBC with platelet count if fever persists or dengue/other infection is possible
  • Urine test, malaria/dengue tests, chest evaluation, or blood culture only when clinically indicated
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
  • Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?
  • Do I need antibiotics, or is this more likely viral?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Safe pathway to proper treatment

Care roadmap for: Siemerling–Creutzfeldt Disease

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

Internal learning pathway

Explore related RX articles

Related guides from RX Harun are grouped to help readers move from overview to symptoms, tests, treatment, and safe next steps.

Rx Autoimmune, Genetic and Rare Diseases (A - Z)
  1. Congenital Enterocyte Heparan Sulfate Deficiency DefinitionCongenital? enterocyte heparan sulfate deficiency is a very rare, severe?, genetic? intestinal disease. In this condition,…
  2. Congenital ectropion uveae DefinitionCongenital? ectropion uveae, often shortened to CEU, is a very rare eye condition present from birth.…
  3. Congenital Dyserythropoietic Anemia, Type III DefinitionCongenital? dyserythropoietic anemia?, type III, also called CDA type III, is a very rare inherited? blood…
  4. Congenital Dyserythropoietic Anemia Type I DefinitionCongenital? dyserythropoietic anemia?, type I, usually called CDA type I, is a rare inherited? blood disease.…
  5. Congenital Dyserythropoietic Anemia Due to KLF1 Mutation DefinitionCongenital? dyserythropoietic anemia? due to KLF1 mutation is a very rare inherited? red blood cell disease.…
  6. Congenital Dyserythropoietic Anemia Due to KLF1 Mutation DefinitionCongenital? dyserythropoietic anemia? due to KLF1 mutation is a very rare inherited? red blood cell disease.…