Antley-Bixler Syndrome (ABS)

Antley-Bixler syndrome is a rare genetic condition that affects how the skull, face, arms, legs, and some internal organs form before birth. The skull bones may fuse too early (craniosynostosis), the middle part of the face can be small and flat, elbows may be stiff because the upper-arm bone and one forearm bone are stuck together (radio-humeral synostosis), long bones can be bowed, and joints may be tight. Some babies—especially those with a certain gene problem called POR deficiency—can also have genital differences (such as ambiguous genitalia) and hormone-making problems of the adrenal glands (steroidogenesis disorders). Other babies—usually those with changes in a different gene called FGFR2—have the bone features without the hormone or genital problems. ABS was first described in 1975 and is very uncommon. BioMed Central+3Orpha.Net+3National Organization for Rare Disorders+3

Antley–Bixler syndrome is a very rare genetic condition that mainly affects the skull and bones. The seams of the skull (sutures) can close too early (craniosynostosis), which changes head shape and can press on the growing brain. The midface may be small and flat. Bones of the arms and legs can be bent, and the elbow may be “fused” (radio-humeral synostosis), making it hard to bend and rotate the forearm. Some babies have breathing blockages in the nose (choanal atresia), joint contractures, and hand or foot differences. Some children also have differences in sex development or hormone problems, especially when the condition is caused by changes in a gene called POR. Overall, ABS is a syndromic craniosynostosis with skeletal and sometimes endocrine features. Orpha.Net+2National Organization for Rare Disorders+2

Other names

Antley-Bixler syndrome is also called trapezoidocephaly-synostosis syndrome in some older writings. When ABS is caused by POR gene problems and includes genital differences and steroid hormone issues, many experts use “Antley-Bixler syndrome with genital anomalies and disordered steroidogenesis (ABS-GA/DS)” or simply “POR deficiency (PORD) with ABS phenotype.” When the picture is only the bone features without genital or steroid problems (often from FGFR2), some sources say “ABS without genital anomalies or disordered steroidogenesis.” Orpha.Net+2Orpha.Net+2

Types

In everyday clinical use, doctors find it helpful to think of two broad types:

1) FGFR2-related ABS (“without GA/DS”).
This group has the skeletal pattern—craniosynostosis, midface hypoplasia, radio-humeral synostosis, bowed femurs, and joint contractures—without consistent genital anomalies or steroid hormone problems. FGFR2 changes act in an autosomal dominant way and are usually new (de novo) in the child. Radiopaedia+2ijbs.com+2

2) POR-related ABS (“with GA/DS”).
This group has the same skeletal pattern plus genital differences and laboratory evidence of disordered steroidogenesis (adrenal/sex-steroid pathways). POR deficiency is autosomal recessive; many children have compound heterozygous POR variants. Hormone testing can show partial cortisol deficiency and altered sex steroid production. Frontiers+3NCBI+3MedlinePlus+3

Practical note: Some databases and reviews simply say “ABS can be caused by FGFR2 or POR changes,” and then specify whether genital/hormone features are present. That is acceptable clinically and helps with counseling and testing. Genetic Rare Diseases Center

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Causes

Because ABS is a pattern of birth differences, “causes” mostly refer to gene changes and how they disrupt growth signals or hormone pathways in the embryo. Below are 20 concrete causes or causal mechanisms clinicians recognize or consider:

1. Pathogenic variants in the POR gene that reduce POR enzyme activity. POR is a key “helper” for many cytochrome P450 enzymes; when it does not work well, steroid hormone synthesis and some developmental pathways are disturbed, giving an ABS-like skeletal pattern plus genital/hormonal problems. NCBI

2. Pathogenic variants in the FGFR2 gene (usually activating/altering the receptor). FGFR2 sends growth signals to developing bone; certain missense changes can prematurely drive skull-suture fusion and other skeletal fusions typical of ABS, usually without genital/hormone issues. ijbs.com

3. Autosomal recessive inheritance for POR deficiency. Children typically inherit one faulty POR copy from each parent. This explains sibling recurrence in POR-related ABS. NCBI

4. Autosomal dominant inheritance for FGFR2-related ABS. A single new (de novo) FGFR2 change can cause the condition, even if parents are unaffected. Rarely, a parent can be mosaic. PubMed

5. Compound heterozygosity in POR. Many children have two different POR variants, one on each chromosome, combining to reduce activity enough to cause disease. Frontiers

6. Common POR “hotspot” variants that recur in certain populations. For example, A287P is common in Caucasian patients and reduces activity to ~40%; R457H is frequent in Japan. These population-specific patterns help labs interpret results. Frontiers+2Oxford Academic+2

7. FGFR2 variants clustered in functional domains. Many craniosynostosis-causing FGFR2 variants occur in the IgIII loop coding exons (8 and 10) or kinase domains; a classic ABS-linked change is S351C. ScienceDirect+2Nature+2

8. Disruption of steroidogenic P450 enzymes downstream of POR. With POR deficiency, enzymes such as CYP17A1 and CYP21A2 cannot work properly, causing altered cortisol/sex-steroid synthesis and leading to genital anomalies in both sexes. NCBI

9. Broader P450 effects beyond steroidogenesis. POR also supports enzymes involved in retinoic acid and drug metabolism; its deficiency likely contributes to skeletal malformations through multiple biochemical routes. Frontiers

10. De novo FGFR2 mutations arising in the parental germline. Even when parents are healthy, a new mutation in egg or sperm can cause ABS in the child. PubMed

11. Unidentified genetic causes in a minority. A few patients with an ABS pattern have no detectable POR or FGFR2 variant using standard methods, suggesting other genes or undetected variants. PubMed

12. Maternal exposure to high-dose, long-term fluconazole (azole antifungals) in early pregnancy can produce an ABS-like embryopathy with craniosynostosis, synostoses, and skeletal/heart anomalies. This is not genetic ABS, but the pattern overlaps. FDA and case reports highlight this risk at 400–800 mg/day in the first trimester. U.S. Food and Drug Administration+2PubMed+2

13. Inhibition of fetal P450 systems by azoles (mechanistic link). Azoles inhibit CYP enzymes; prolonged high exposure during organ formation can mimic features seen with POR dysfunction. PMC

14. Consanguinity (for POR-related ABS). When parents are related, the chance of both carrying the same rare POR variant rises, increasing risk for autosomal recessive disease. (This is a general genetics principle supported by PORD case clusters.) PMC

15. Gonadal or somatic mosaicism in a parent (FGFR2). Very rarely, a parent with low-level mosaicism can pass on a dominant FGFR2 variant even if outwardly unaffected. PubMed

16. Missense variants that alter disulfide bonds in FGFR2. Cysteine-creating changes in key domains can force abnormal receptor dimerization and signaling, hastening suture fusion. (Shown across FGFR2 craniosynostosis syndromes and relevant to ABS.) Nature

17. POR variants that destabilize the protein. Some mutations reduce POR stability or electron transfer efficiency, impairing multiple downstream enzymes and contributing to the ABS phenotype. PMC

18. Known POR variant combinations with particularly severe skeletal effects. Certain allele pairs (e.g., A287P with another loss-of-function variant) correlate with more striking malformations. (Genotype-phenotype analyses of PORD support this.) Oxford Academic

19. Broader FGFR pathway dysregulation. Work on FGFR craniosynostosis shows that altered signaling during the fourth to eighth embryonic weeks can affect axial and cranial development, consistent with features seen in ABS. PubMed

20. Rare overlapping or modifier genes not yet fully defined. Evolving studies in craniosynostosis and PORD suggest additional variants may modify severity, explaining clinical variability. (Research cohort summaries note heterogeneity.) BioMed Central

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Symptoms and signs

1. Unusual head shape from early skull-suture fusion (craniosynostosis). The skull can be short front-to-back and wide side-to-side (brachycephaly), often due to both coronal sutures fusing early; other sutures can be involved. This can raise intracranial pressure and affect eye position. GOSH Hospital site

2. Midface hypoplasia. The cheekbones and upper jaw may be under-developed, giving a flat midface and relative bulging eyes. This can affect breathing and dental alignment. National Organization for Rare Disorders+1

3. Proptosis or prominent eyes. Because the midface and eye sockets are shallow, the eyes may appear prominent, which can dry the corneas and require protection. Orpha.Net

4. Nasal/airway blockage and choanal atresia/stenosis. Some babies have blocked back-of-nose passages, noisy breathing, or respiratory distress, especially when feeding or sleeping. National Organization for Rare Disorders

5. Radio-humeral synostosis and elbow stiffness. The upper arm (humerus) and radius can be fused, limiting elbow motion; daily activities and physical therapy plans must adapt. Orpha.Net

6. Bowed femurs and other long-bone changes. Thigh bones can curve, and other long bones may be affected, influencing mobility and fracture risk. Orpha.Net

7. Joint contractures. Some joints are tight at birth, reducing range of motion in arms, legs, or fingers; early therapy helps prevent stiffness. Orpha.Net

8. Hand/foot differences (e.g., camptodactyly). Finger joint bending or limited extension can occur; supportive splinting may help. BioMed Central

9. Genital differences in POR-related cases. Males can have micropenis, hypospadias, or undescended testes; females can have clitoromegaly or vaginal atresia. These reflect disrupted fetal sex-steroid pathways. Translational Pediatrics

10. Adrenal hormone problems (PORD). Some babies cannot mount an adequate cortisol response to stress and may be at risk for low blood sugar or poor stress response; careful endocrine testing is needed. NCBI

11. Feeding difficulties and poor weight gain. Midface structure and airway issues can make feeding hard; a multidisciplinary team helps. National Organization for Rare Disorders

12. Hearing issues. Middle-ear shape and skull base differences can cause conductive hearing loss; newborn hearing checks are important. National Organization for Rare Disorders

13. Heart differences in some children. Congenital heart defects have been reported occasionally, so a screening heart ultrasound is common. BioMed Central

14. Kidney/urinary tract anomalies in some children. Because ABS can be part of broader skeletal development issues, a kidney ultrasound may be advised. BioMed Central

15. Developmental or breathing concerns. Sleep-disordered breathing or intermittent airway obstruction can occur; early evaluation helps protect the brain and growth. National Organization for Rare Disorders

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Diagnostic tests

Physical exam

1) Detailed newborn and craniofacial exam.
The clinician looks at head shape, feels the skull sutures, checks eye position, midface growth, jaw size, palate, and nose openings. This first step suggests craniosynostosis and midface hypoplasia typical of ABS. GOSH Hospital site

2) Musculoskeletal exam of arms and legs.
Elbow movement is checked for stiffness; clinicians palpate for a fused radio-humeral joint and look for bowed femurs and joint contractures. Hand posture and finger flexibility are also assessed. Orpha.Net

3) Airway and feeding assessment.
Bedside checks for nasal patency (can air pass through each nostril?), breathing effort, noisy breathing, and feeding coordination help reveal choanal obstruction or midface-related airway narrowing. National Organization for Rare Disorders

4) Genital exam (when ABS-GA/DS is suspected).
In POR-related cases, a careful, respectful inspection documents any differences and guides hormone testing and future surgical/endocrine planning. MedlinePlus

Manual/bedside tests

5) Anthropometric measurements.
Head circumference, cranial index, midface and jaw measurements, limb lengths, and segment ratios are recorded over time to track growth and shape changes that point to craniosynostosis and limb involvement. GOSH Hospital site

6) Passive range-of-motion (PROM) testing.
Gentle movement of elbows, shoulders, hips, knees, and ankles identifies contractures and synostoses that limit motion; this helps plan early therapy. Orpha.Net

7) Bedside nasal patency tests.
Simple tests—such as observing fog on a mirror near the nostrils or saline drop passage—can suggest choanal narrowing and trigger imaging. National Organization for Rare Disorders

8) Newborn hearing screen (OAE/ABR screen).
Although formal ABR is an electrodiagnostic test, many hospitals start with a quick automated screen to flag possible conductive hearing loss common in craniofacial syndromes. National Organization for Rare Disorders

Lab and pathological tests

9) Basal steroid hormone profile.
Blood and/or urine tests look at cortisol, 17-hydroxyprogesterone, DHEA, androstenedione, testosterone/estradiol patterns; in POR deficiency these can be atypical, supporting ABS-GA/DS. NCBI

10) ACTH stimulation test (cosyntropin test).
This checks whether the adrenal glands can raise cortisol when stressed; many PORD patients have partial cortisol deficiency (normal baseline but poor rise). NCBI

11) Urinary steroid metabolome/profiling.
Comprehensive urine testing shows a “signature” pattern of multiple enzyme bottlenecks when POR is deficient, aiding diagnosis and variant interpretation. Oxford Academic

12) Genetic testing for POR and FGFR2.
Targeted sequencing or panels detect pathogenic variants; finding biallelic POR variants supports ABS-GA/DS, while a heterozygous FGFR2 variant supports ABS without GA/DS. Radiopaedia

13) Chromosomal microarray / exome sequencing (when targeted tests are negative).
If initial genes are negative, broader tests can look for rare or novel causes reported in a small minority. PubMed

14) Electrolytes and glucose monitoring in infants.
Because cortisol helps maintain sugar and salt balance under stress, labs may track for hypoglycemia or other stress-related changes in suspected POR cases. NCBI

Electrodiagnostic tests

15) Diagnostic auditory brainstem response (ABR).
Formal ABR measures the hearing pathway with small electrodes. It clarifies type and degree of hearing loss common in craniofacial syndromes. National Organization for Rare Disorders

16) Polysomnography (sleep study) when airway obstruction is suspected.
ABS midface and nasal differences can cause sleep-disordered breathing; a sleep study records airflow, oxygen, and brain/eye/muscle signals overnight to guide airway treatment. National Organization for Rare Disorders

17) EEG if there are concerning events.
If a baby/child has spells that look like seizures (e.g., due to hypoxia from airway obstruction), EEG helps confirm and guide care. (Used selectively.) National Organization for Rare Disorders

Imaging tests

18) Low-dose CT of the skull with 3-D reconstruction.
This is the standard way to confirm which sutures are fused and plan craniofacial surgery when needed; it shows shallow orbits and skull base shape. Radiopaedia

19) Skeletal survey (plain X-rays).
X-rays of arms and legs check for radio-humeral synostosis, bowed femurs, vertebral anomalies, and hand/foot differences, forming the classic ABS skeletal pattern. Orpha.Net

20) Brain MRI (selected cases).
MRI can look for raised intracranial pressure effects or associated brain differences and plan safe surgical timing. (Used when clinically indicated.) Orpha.Net

21) Echocardiogram.
Because congenital heart problems are sometimes present, a screening ultrasound of the heart is often done in infancy. BioMed Central

22) Renal and pelvic ultrasound.
An ultrasound checks kidneys/urinary tract and, in POR-related cases, documents internal reproductive structures to guide endocrine and surgical care. BioMed Central

23) Prenatal ultrasound and, if needed, fetal MRI.
Severe limb bowing, craniosynostosis, or facial differences can be seen before birth; families may be counseled and delivery planned at a specialty center. SAGE Journals

24) Nasal endoscopy or CT of the nasal cavity (selected).
If choanal atresia/stenosis is suspected, imaging or endoscopy confirms the blockage to plan surgery or stenting. National Organization for Rare Disorders

Non-pharmacological treatments

Note: Non-drug care is the foundation. Many items run in parallel under a craniofacial team (neurosurgery, plastic/ENT, orthodontics, endocrinology, genetics, audiology, PT/OT/SLP).

1. Craniofacial team care & surveillance.
   Description. A coordinated clinic follows head growth, eye protection, airway, feeding, hearing, and development from birth through adolescence. The team times imaging, surgeries, orthodontics, and therapy to the child’s growth. Parents get education and home-care plans. Purpose. Reduce complications (raised ICP, corneal injury, OSA, malnutrition) and plan the safest sequence of operations. Mechanism. Regular multidisciplinary review catches problems early; combining surgical, airway, dental, and developmental planning improves outcomes and reduces anesthesia exposures. PMC

2. Airway and breathing management.
   Description. ENT assesses choanal atresia/stenosis and midface-related airway narrowing; nursing teaches positioning and suction; CPAP or nasal stents may be used short-term; definitive surgery is planned if obstruction persists. Purpose. Keep oxygen, sleep, and feeding safe while the face/skull plan is finalized. Mechanism. Opening nasal passages and stabilizing airway dynamics prevents hypoxia and growth failure. PMC

3. Feeding and swallowing therapy.
   Description. A speech-language pathologist evaluates suck–swallow–breath coordination, modifies nipple flow, and recommends thickening or pacing as needed. Purpose. Assure enough calories and prevent aspiration. Mechanism. Technique and texture changes match the baby’s airway and craniofacial anatomy, improving efficiency and safety. PMC

4. Physical therapy for joints and posture.
   Description. PT provides gentle range-of-motion and stretching to limit contractures and compensate for elbow fusion; core and neck work supports head control in atypical skull shapes. Purpose. Preserve function and independence. Mechanism. Repeated low-load stretch and motor learning maintain joint length and teach alternative movement strategies. PMC

5. Occupational therapy for daily skills.
   Description. OT adapts self-care tasks (dressing, feeding, writing) around limited forearm rotation; custom splints or tools improve grip. Purpose. Maximize daily independence. Mechanism. Activity analysis and adaptive equipment bypass the mechanical block from synostosis. PMC

6. Vision protection and eye-surface care.
   Description. With proptosis, families learn eyelid lubrication, taping while asleep if needed, and urgent signs of exposure keratopathy; ophthalmology watches optic nerves if ICP risk. Purpose. Prevent corneal injury and vision loss. Mechanism. Moisture protection and early surgery (fronto-orbital advancement) reduce exposure. PMC

7. Hearing rehabilitation (audiology).
   Description. Serial ABR/tympanometry guide early hearing aids or ventilation tubes if middle-ear dysfunction occurs. Purpose. Protect language development. Mechanism. Restoring hearing input in the first years supports normal speech and learning. ScienceDirect

8. Sleep care (OSA management).
   Description. Snoring, pauses, or restless sleep trigger study and treatment (positioning, CPAP, or earlier midface advancement). Purpose. Prevent neurocognitive effects of sleep apnea. Mechanism. Normalizing airway patency during sleep improves oxygen and brain development. PMC

9. Orthodontic and dentofacial orthopedics.
   Description. An orthodontist plans dental arch guidance and coordinates with midface advancement timings; oral hygiene support prevents caries in crowded arches. Purpose. Improve bite, speech, and facial balance. Mechanism. Growth-guided appliances and staged surgery correct skeletal discrepancies. SAGE Journals

10. Family genetic counseling.
    Description. Counselors explain POR vs FGFR2 inheritance (recessive vs dominant), recurrence risk, carrier testing, and prenatal options. Purpose. Enable informed family planning and early care. Mechanism. Clarifying gene-level risk supports testing of relatives and timely prenatal/newborn planning. NCBI+1

11. Low-vision/education supports (if eye or hearing issues persist). Purpose/Mechanism. Classroom accommodations and assistive tech maintain learning pace. ScienceDirect

12. Scar and cranial incision care education post-surgery to prevent infection and protect bone. Purpose/Mechanism. Better wound hygiene reduces complications. e-Publications

13. Pain psychology and coping skills around repeated surgeries. Purpose/Mechanism. Lowers anxiety, improves adherence and recovery. SAGE Journals

14. Nutrition optimization (high-calorie strategies if feeding is slow; salt guidance in POR-ABS per endocrine plan). Purpose/Mechanism. Supports growth and hormone treatment. NCBI

15. Developmental therapies (early intervention) for speech/motor delay risk. Purpose/Mechanism. Repetitive practice builds skills despite sensory/airway hurdles. PMC

16. Sun/eye protection for exposure-prone eyes. Purpose/Mechanism. Preserve corneal health. PMC

17. Peri-anesthetic planning (difficult airway). Purpose/Mechanism. Reduces anesthesia complications in midface hypoplasia. PMC

18. Community support & parent training. Purpose/Mechanism. Better home monitoring for breathing, feeding, and wound care. SAGE Journals

19. Avoidance of teratogens in future pregnancies (no prolonged high-dose fluconazole in first trimester). Purpose/Mechanism. Reduces ABS-like azole embryopathy risk. U.S. Food and Drug Administration

20. Planned delivery at a tertiary craniofacial center for high-risk pregnancies. Purpose/Mechanism. Immediate airway and feeding support improves outcomes. PMC

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Drug treatments

Important: There is no single “ABS medicine.” Drugs are used to (1) treat hormone imbalances in POR-ABS, and (2) support surgery/airway/feeding. Doses vary by age, weight, and labs—endocrinology must individualize.

1. Hydrocortisone (glucocorticoid).
   Class. Short-acting steroid. Typical pediatric dosing. ~8–12 mg/m²/day in 3 divided doses; stress dosing during illness/surgery per endocrine protocol. Time/Purpose. Daily to replace cortisol if deficient and to suppress ACTH, lowering buildup of steroid precursors. Mechanism. Replaces cortisol and reduces overstimulation of steroid pathways impaired by POR. Side effects. Excess can slow growth, raise glucose, and thin skin; under-dosing risks adrenal crisis. NCBI

2. Fludrocortisone (if mineralocorticoid needed).
   Class. Mineralocorticoid. Dose. Often 0.05–0.2 mg/day, titrated to renin/electrolytes. Purpose. Maintain salt and blood pressure. Mechanism. Replaces aldosterone effect when mineralocorticoid function is low. Side effects. Hypertension, edema, low potassium if over-treated. NCBI

3. Sodium chloride supplementation (infancy, as directed).
   Class. Electrolyte therapy. Dose. Per kg/day based on labs. Purpose. Support salt balance in mineralocorticoid-sensitive infants. Mechanism. Compensates for aldosterone deficiency. Side effects. GI upset; requires lab monitoring. NCBI

4. Physiologic sex-steroid replacement at puberty (estradiol or testosterone led by endocrinology).
   Class. Sex steroids. Dose/Time. Pubertal induction per standard DSD/CAH protocols. Purpose. Support normal pubertal development. Mechanism. Replaces missing hormones because POR impairs synthesis. Side effects. Acne, mood or BP changes; monitored carefully. PubMed

5. Aromatase management (maternal virilization context).
   Class. Endocrine supportive care in pregnancy (specialist-led). Purpose/Mechanism. Address POR-related aromatase impairment affecting maternal/fetal hormone balance; managed by high-risk OB and endocrinology. Risks. Teratogen avoidance emphasized. NCBI

6. Peri-operative antibiotics (short course).
   Class. Antimicrobials. Time. Around cranial and midface surgeries. Purpose. Prevent surgical site infection. Mechanism. Reduce bacterial load at incision. Side effects. GI upset, allergy. e-Publications

7. Analgesia protocols (acetaminophen ± opioids short-term).
   Class. Analgesics. Time. Post-op. Purpose. Pain control for craniofacial/orthopedic surgery. Mechanism. Multimodal pain relief speeds recovery. Side effects. Constipation, sedation (opioids). e-Publications

8. Intranasal steroids/saline (ENT-supervised) post-choanal surgery.
   Class. Topical anti-inflammatory/saline. Purpose. Reduce edema, maintain stent patency. Side effects. Local irritation, epistaxis. PMC

9. Vitamin D and calcium (if deficient).
   Class. Supplements. Purpose. Bone health during rapid growth and post-op healing. Mechanism. Supports mineralization. Side effects. Hypercalcemia if overused. PMC

10. Antireflux meds (if aspiration risk).
    Class. Acid suppression. Purpose. Protect airway/lungs if reflux worsens feeding safety. Side effects. Diarrhea, microbiome changes. PMC

Additional endocrine agents (e.g., low-dose dexamethasone at night to suppress ACTH, pubertal modulators) may be considered case-by-case by endocrinology. The exact drug set depends on lab patterns in POR-ABS. NCBI

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Dietary molecular supplements

1. Sodium chloride (as above) for mineralocorticoid-sensitive infants; it is “dietary” when provided via feeds. Function/Mechanism. Restores sodium balance to prevent dehydration and failure to thrive. Dose. Per endocrinology. NCBI

2. Vitamin D3 if low. Function. Supports bone mineralization and healing. Mechanism. Improves calcium absorption. Dose. Pediatric-appropriate per labs. PMC

3. Calcium (dietary or supplement, if needed). Function. Bone strength post-op and during growth. Mechanism. Mineral substrate. Dose. Per age and labs. PMC

4. Iron when deficient (common in medically complex kids). Function. Prevents anemia-related fatigue, supports wound healing. Mechanism. Replaces iron stores. Dose. Per pediatric guidelines. PMC

5. Energy-dense feeds (MCT-added formulas where appropriate). Function. Meet high caloric needs when feeding is slow. Mechanism. Easier calorie delivery. Dose. Dietitian-led. PMC

6. Zinc (if low). Function. Wound and immune support. Mechanism. Cofactor for tissue repair. Dose. Lab-guided. PMC

7. Iodine-adequate diet (thyroid health). Function. Supports growth; thyroid interacts with skeletal development. Mechanism. Ensures normal thyroid hormone production. Dose. RDA-based. PMC

8. Protein optimization (whey/peptide formulas if needed). Function. Healing and growth. Mechanism. Supplies amino acids post-op. Dose. Dietitian-guided. PMC

9. Omega-3s from food (fish twice weekly if culturally suitable). Function. General anti-inflammatory support. Mechanism. Membrane lipid balance. Dose. Dietary pattern. PMC

10. Fiber and fluids to prevent opioid-related constipation post-op. Function/Mechanism. Keeps bowels moving. Dose. Age-appropriate. e-Publications

Caution: Avoid “hormone-modulating” supplements without endocrine approval—POR-ABS involves delicate steroid pathways. NCBI

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Immunity booster / regenerative / stem-cell drugs

There are no proven “immunity booster,” regenerative, or stem-cell drugs for Antley–Bixler syndrome. Using such products outside a clinical trial is not evidence-based and could be harmful, especially in children with POR-related steroid issues that change drug handling. Safer alternatives are the multidisciplinary non-drug care above, endocrine management when indicated, and timed craniofacial/orthopedic surgery. NCBI+1

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Surgeries

1. Cranial vault remodeling and fronto-orbital advancement.
   Procedure. Neurosurgery/plastic surgery open and reshape fused sutures and move the forehead/orbits forward. Why. Relieve/avoid raised intracranial pressure, protect vision, and improve skull/forehead shape. e-Publications+1

2. Midface advancement (Le Fort III) or monobloc distraction osteogenesis.
   Procedure. The midface (and sometimes forehead) is cut and gradually advanced using distractors—often with virtual surgical planning. Why. Opens the airway, reduces eye exposure, and improves occlusion/facial balance. SAGE Journals+1

3. Choanal atresia repair.
   Procedure. Endoscopic opening of the blocked back-of-nose passage, sometimes with stents. Why. To restore nasal breathing and feeding safety. PMC

4. Orthopedic procedures for femoral bowing or fractures.
   Procedure. Guided growth, osteotomy, or fracture stabilization as needed. Why. Improve alignment and mobility. PMC

5. Urogenital reconstructive surgery (selected cases).
   Procedure. Individualized procedures in DSD settings after shared decision-making. Why. To address function (urinary/sexual) and health needs; timing is carefully considered with the family. PubMed

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Prevention & risk-reduction tips

1. Genetic counseling for POR (recessive) and FGFR2 (dominant) forms; discuss carrier and prenatal options. NCBI+1

2. Avoid prolonged high-dose fluconazole in the first trimester unless life-saving; use safer alternatives under OB guidance. U.S. Food and Drug Administration

3. High-risk obstetric care with planned delivery at a craniofacial center if ABS is suspected. PMC

4. Newborn evaluation early (airway, feeding, imaging). PMC

5. Routine hearing and vision screening in infancy. ScienceDirect

6. Sleep apnea screening in toddlers with midface hypoplasia. PMC

7. Growth and nutrition tracking with a dietitian. PMC

8. Vaccinations on time (no ABS-specific contraindications typically; coordinate peri-operative timing). PMC

9. Wound and scar care education after surgeries. e-Publications

10. Emergency steroid plan for POR-ABS (stress dosing card/kit). NCBI

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When to see a doctor (red flags)

See a doctor immediately for: noisy breathing, blue spells, pauses in breathing, poor feeding, vomiting with dehydration, lethargy or fever after recent surgery, bulging soft spot or worsening headache/irritability (possible raised ICP), eye redness/pain from exposure, or any illness in a child on steroid replacement (needs stress dosing). For new pregnancies in a family with ABS history, see a genetic counselor and high-risk OB before or as soon as pregnancy is confirmed. PMC+1

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What to eat & what to avoid

What to eat: balanced, calorie-adequate diet; breastmilk or appropriate formula with added calories if needed; age-appropriate protein and iron sources; fruits/vegetables; enough calcium and vitamin D (per labs); sufficient salt in infancy only if directed for mineralocorticoid support. Why: growth and wound healing need extra energy and building blocks; POR-ABS infants may need salt to stay well hydrated. NCBI+1

What to avoid: unapproved “hormone” supplements; herbal products that affect steroid metabolism; high-dose fluconazole in early pregnancy; smoking exposure (wound healing); excessive sugary drinks that displace nutritious foods. Why: POR-ABS involves sensitive steroid pathways; teratogens and metabolism-altering products can harm development or interact with medications. U.S. Food and Drug Administration+1

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Frequently Asked Questions

1. Is ABS inherited? Yes. FGFR2-ABS is usually autosomal dominant (often a new mutation); POR-ABS is autosomal recessive (two POR variants). NCBI+1

2. Can we test for it? Yes. Genetic testing of POR and FGFR2 confirms the diagnosis and guides family counseling. ScienceDirect

3. Does every child have hormone problems? No. Hormone issues are typical of POR-ABS; FGFR2-ABS usually lacks endocrine problems. PMC

4. Is surgery always needed? Many children need at least one cranial surgery; some also need midface or airway operations as they grow. PMC

5. Will my child’s intelligence be normal? Many children do well, especially with early care; uncontrolled raised intracranial pressure, OSA, or hearing loss can affect development—hence close monitoring. PMC

6. Can helmets fix craniosynostosis? No. Helmets help positional skull flattening, not fused sutures; surgery is the treatment for synostosis. PMC

7. Is there a medicine that “cures” ABS? No. Medicines treat hormone imbalance (POR-ABS) and surgical recovery; surgery addresses skull/airway structure. NCBI+1

8. Are there stem-cell or regenerative drugs? Not at this time; none are proven or recommended for ABS. PMC

9. What about pregnancy safety? Avoid long-term, high-dose fluconazole early in pregnancy; ask OB about safer antifungal strategies. U.S. Food and Drug Administration

10. Can ABS be found before birth? Sometimes—ultrasound or fetal MRI may show skull shape, limb bowing, or elbow fusion; genetic testing can confirm. PMC

11. Why do eyes look prominent? The orbits are shallow from midface/forehead shape; eye protection and timed surgery reduce risk. PMC

12. Will my child need special schooling? Not necessarily; hearing/vision support and early therapies often keep learning on track. ScienceDirect

13. Are drug doses standard? Steroid and salt dosing are individualized by endocrinology using growth and lab targets. NCBI

14. Is ABS the same as other FGFR syndromes? It overlaps but has its own pattern (notably radiohumeral synostosis); genetics clarifies the subtype. NCBI

15. Where can I find reliable summaries? Orphanet and NORD provide patient-friendly overviews; GeneReviews covers POR deficiency in depth. Orpha.Net+1

Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic 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 20, 2025.

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