Cenani-Lenz Syndactyly Syndrome (CLSS)

Cenani–Lenz syndactyly syndrome (often shortened to CLS or CLSS) is a rare condition a baby is born with. It mainly affects how the hands, feet, and forearm bones form before birth. The most typical finding is complex syndactyly, which means two or more fingers or toes are joined together, and sometimes the bones inside are also joined or mixed up, not only the skin. Many people also have shortened or unusually shaped radius and ulna bones in the forearm, and some have kidney problems such as a missing or smaller kidney. Orpha.net+2NCBI+2

Cenani-Lenz syndactyly syndrome (CLSS) is a very rare genetic condition (usually autosomal recessive) that mainly affects the hands and feet (severe syndactyly, unusual bones, shortened forearm bones, and sometimes radioulnar synostosis), and it can also include kidney differences in many people. NCBI+1

There is no single “cure” medicine that fixes the gene change in CLSS today, so treatment focuses on function, safety, comfort, and preventing complications using surgery, therapy, adaptive tools, and careful medical follow-up. Orpha.net+1

Another names

Doctors and genetic labs may use different names for the same condition. Common names you may see include Cenani–Lenz syndrome, Cenani–Lenz syndactyly syndrome, and CLSS. In some medical databases it is also linked with the gene name LRP4-related limb malformation (because many cases are caused by changes in the LRP4 gene). NCBI+2NCBI+2

Types

These “types” are not always official subtypes, but they are useful clinical patterns doctors use because the condition can look milder or more severe in different people. Orpha.net+2NCBI+2

• Classic (typical) CLSS pattern: complex syndactyly of hands/feet plus forearm bone changes (like shortened bones or radioulnar fusion). Orpha.net+1

• CLSS with kidney involvement: limb findings plus kidney anomalies such as renal hypoplasia (small kidney) or renal agenesis (missing kidney). NCBI+1

• Milder / limb-dominant pattern: mainly hand/foot changes, with fewer extra findings outside the limbs. This is reported in families and case descriptions, showing that severity can vary. PMC+1

• Overlap pattern reported in literature: some people with LRP4 changes can have CLSS features together with other LRP4-related features discussed in research (for example, bone or neuromuscular overlap in specific reports). This does not mean all CLSS patients have these issues, but it explains why doctors sometimes check more systems. Nature+1

Causes

Important note (so it stays accurate): CLSS itself is usually caused by biallelic (two-copy) harmful changes in the LRP4 gene. But when a patient presents with syndactyly and bone fusion, doctors also consider other causes that can look similar before confirming CLSS by imaging and genetic testing. Below are 20 recognized causes of syndactyly/complex limb fusion that can enter the differential diagnosis. NCBI+2NCBI+2

1. Cenani–Lenz syndactyly syndrome (CLSS) from LRP4 variants: This is the key cause for this topic. LRP4 loss of function has been shown to cause syndactyly, bone fusion, and kidney anomalies in CLSS. PMC+1

2. Inherited (familial) isolated syndactyly: Some syndactyly happens mainly in the digits without a broader syndrome, and it can run in families. Doctors ask about family history for this reason. GOSH Hospital site+1

3. Sporadic (chance) isolated syndactyly: Syndactyly can also occur “by chance,” without a known family history, especially in mild toe webbing. GOSH Hospital site+1

4. Apert syndrome: A well-known craniosynostosis syndrome where syndactyly can be a major feature; it is listed in medical differential diagnosis resources for syndactyly. NCBI+1

5. Poland syndrome: This condition can include chest wall differences and limb differences; it is also listed as a differential diagnosis when evaluating syndactyly. NCBI+1

6. Carpenter syndrome: Another syndrome that can include syndactyly/polysyndactyly; it is listed among standard differentials for syndactyly. NCBI+1

7. Synpolydactyly: This means a mix of syndactyly and extra digits; it is specifically named in syndactyly differential diagnosis references. NCBI

8. Oculodentodigital dysplasia: A genetic syndrome that can include syndactyly and is included in major differential diagnosis lists. NCBI

9. Ectrodactyly (cleft hand/foot): Some children have split hand/foot patterns that can be confused with severe digit malformations; it is listed as a differential diagnosis for syndactyly presentations. NCBI

10. Constriction band syndrome (amniotic band sequence): Fibrous bands in pregnancy can wrap around digits and change how they form, sometimes causing fused or missing parts. NCBI+1

11. Amniotic band syndrome (general clinical explanation): Large pediatric and hospital references describe how amniotic strands can entangle parts of the fetus and cause limb differences. fetus.ucsf.edu+1

12. Down syndrome (can include syndactyly/webbing): Some chromosomal conditions can be associated with webbed digits in a subset of patients, so clinicians keep chromosomal causes in mind when other signs fit. Verywell Health

13. Bardet–Biedl syndrome (can include syndactyly): Some multisystem genetic syndromes list syndactyly as an associated feature, so doctors look for vision, growth, and kidney clues if suspected. Verywell Health

14. Pfeiffer syndrome (acrocephalosyndactyly group): This craniosynostosis syndrome can include soft-tissue syndactyly and is described in clinical references. NCBI

15. Other “syndromic” syndactyly (many possible syndromes): Children’s hospital resources note that syndactyly can be part of a broader syndrome, which is why doctors examine the whole child, not only the hand/foot. Children’s Hospital of Philadelphia+1

16. Genetic disruption of normal digit separation in early development: Patient education resources explain that fingers start as a paddle and separate later; problems in that process (often genetic) can cause webbing/fusion. Doc Library+1

17. Environmental/toxin-related disruption (rarely discussed but recognized in counseling materials): Some hospital leaflets mention that disruption of normal embryo development (including toxic exposures) can be part of the discussion for some congenital limb differences, even when a single cause is not proven. St George’s Hospital

18. Non-genetic unknown cause (idiopathic): Many cases of syndactyly have no single clear cause identified, especially mild forms, so “unknown cause” remains a real category in clinical practice. GOSH Hospital site+1

19. LRP4-related phenotypic spectrum considerations: LRP4 is linked to multiple conditions in curated gene–disease resources, so clinicians may consider whether a patient’s findings fit CLSS alone or overlap in rare situations. GenCC Search+1

20. Autosomal recessive inheritance situation (two carrier parents): For CLSS specifically, a common “why” is that both parents carry one non-working copy of the gene, and the child inherits both copies, leading to the condition. NCBI+1

Symptoms and signs

1. Complex syndactyly of the hands: Fingers can be joined in a complicated way. It may involve skin and also bones, so the hand can look “merged” and the finger bones may not be arranged normally. Orpha.net+1

2. Complex syndactyly of the feet: Toes can also be joined, sometimes severely, and the bones in the toes can be fused or shaped differently. NCBI+1

3. Fusion and disorganization of finger bones (metacarpals/phalanges): In CLSS, the internal hand bones can be fused together or placed in unusual patterns, which is why X-rays are so helpful. NCBI+1

4. Oligodactyly (fewer fingers or toes than usual): Some people may have fewer digits because parts of a digit did not form fully during development. search.clinicalgenome.org+1

5. Forearm bone shortening (radius/ulna): The radius and ulna can be shorter than usual, which changes forearm shape and can limit motion. NCBI+1

6. Radioulnar synostosis (radius and ulna joined together): Sometimes the two forearm bones are connected, which can reduce the ability to rotate the forearm (turning the palm up and down). NCBI+1

7. Limited forearm rotation (functional problem): Because of bone fusion or bone shape, a person may have trouble with movements like turning a key or rotating the hand fully. NCBI+1

8. Abnormal wrist/hand alignment: When bones are fused or shortened, the wrist and hand may sit at an unusual angle, which can affect grip and hand use. Orpha.net+1

9. Stiffness of affected joints: Joined bones and tight soft tissues can make joints stiff, especially in the fingers, wrist, or forearm. NCBI+1

10. Mild facial differences (mild facial dysmorphism): Some reports describe mild facial differences in many patients, but it is usually not the main problem compared with the limb findings. NCBI+1

11. Kidney anomalies (general category): Kidney problems are reported in a large portion of patients in major summaries, so doctors often screen the kidneys even if the child has no urinary symptoms. NCBI+1

12. Renal agenesis (missing kidney): Some CLSS patients have one kidney that did not form, which can be found on ultrasound and may change long-term monitoring needs. NCBI+1

13. Renal hypoplasia (small kidney): A kidney can form but be smaller than normal, which can reduce kidney reserve and may need follow-up. NCBI+1

14. Horseshoe kidney (reported in some cases): Some case-based literature has described horseshoe kidney in LRP4-related cases that show CLSS features, so ultrasound can look for this too. Nature

15. Variable severity even in the same family: Medical case reports show that some affected relatives can look more severe or more mild, which is common in rare genetic limb conditions. PMC+1

Diagnostic tests

Physical exam (doctor looks and checks with hands and eyes)

1. Full newborn/child physical exam: The clinician checks the whole child, not only hands/feet, because syndactyly can be isolated or part of a syndrome. NCBI+1

2. Detailed hand and foot inspection: The doctor looks at which digits are joined, whether the joining is skin-only or likely bone-involved, and whether both sides are affected. GOSH Hospital site+1

3. Counting digits and identifying missing parts (oligodactyly check): The clinician checks if any finger/toe is absent or unusually small, which supports a complex limb-development diagnosis like CLSS. NCBI+1

4. Forearm shape and elbow/wrist alignment exam: The doctor checks for signs of shortened radius/ulna and looks for limited rotation that suggests radioulnar synostosis. NCBI+1

Manual tests (simple bedside function tests done by hand)

5. Range of motion testing (fingers/wrist/forearm): The clinician gently measures how far joints bend and rotate, because fused bones and tight tissues can limit movement. Orthobullets+1

6. Grip and pinch strength (age-appropriate): In older children, simple grip and pinch checks help show how the hand structure affects daily function. Orthobullets+1

7. Neurovascular check (sensation and blood flow in digits): The examiner checks feeling in the fingertips and signs of good blood flow, which matters for safety and for any surgical planning. Orthobullets+1

8. Functional task observation: Watching simple tasks (holding objects, picking up small items) helps the team understand real-life limits caused by the malformation. Orthobullets+1

Lab and pathological / genetic tests (tests on blood/saliva and DNA)

9. Targeted gene testing for LRP4: Many clinical laboratories list tests for CLSS, and sequencing LRP4 is a direct way to confirm the genetic diagnosis. NCBI+1

10. Sequencing to find small DNA changes (single-letter variants): Sequencing reads the gene code and can detect missense, nonsense, and small insertion/deletion changes reported in CLSS research. PMC+1

11. Deletion/duplication testing (copy-number testing): Some genetic workflows add tests that look for missing or extra parts of the gene if sequencing alone does not explain the condition. NCBI+1

12. Carrier testing for parents (after a child is diagnosed): Because CLSS is typically autosomal recessive, testing parents can confirm carrier status and help with genetic counseling. NCBI+1

13. Chromosomal testing when features suggest another syndrome: If the child has signs pointing away from CLSS and toward a chromosomal condition, chromosomal testing may be used as part of evaluation. Children’s Hospital of Philadelphia+1

Electrodiagnostic tests (nerve–muscle testing, only when indicated)

14. EMG/NCS (electromyography and nerve conduction studies) when weakness is suspected: CLSS is mainly a limb-formation condition, but rare literature reports LRP4-related overlap with neuromuscular issues, so electrodiagnostics are considered only if symptoms suggest it. Nature+1

15. Repetitive nerve stimulation (special test for fatigable weakness) if clinically needed: This is not routine for CLSS, but may be used if a specialist suspects a neuromuscular junction problem in an unusual case. Nature+1

Imaging tests (pictures of bones and organs)

16. X-ray of hands and feet: X-rays show whether fusion is skin-only or includes bone fusion and bone disorganization, which is central in CLSS descriptions. NCBI+1

17. X-ray of forearm (radius/ulna): This helps confirm shortening, abnormal shape, and radioulnar synostosis (bone joining), which is a classic CLSS feature. NCBI+1

18. Renal (kidney) ultrasound: Because kidney anomalies are reported in many patients, ultrasound is a safe way to check for missing, small, or abnormally shaped kidneys. NCBI+1

19. Prenatal ultrasound (during pregnancy) when limb anomaly is suspected: Some severe limb differences can be seen before birth, and prenatal imaging can guide counseling and planning. St George’s Hospital+1

20. CT or MRI in selected cases (surgical planning or complex anatomy): Advanced imaging is not always needed, but it can help in very complex bone fusion cases when surgeons need a 3D understanding. Orthobullets+1

Non-pharmacological treatments (therapies and other supports)

1) Hand occupational therapy (OT) after surgery. OT retrains fingers to move separately, reduces stiffness, helps swelling/scars, and improves daily skills like writing and buttoning. Purpose: better function. Mechanism: guided exercises + task practice + scar care. Shriners Children’s+1

2) Physical therapy (PT) for arm motion and strength. PT supports shoulder/elbow/wrist strength and helps children adapt if rotation is limited. Purpose: easier daily movement. Mechanism: stretching + strengthening + motor learning. Boston Children’s Hospital+1

3) Splinting to keep fingers separated after release. Splints can protect healing skin grafts and help keep the web space open. Purpose: prevent re-tightening/contracture. Mechanism: gentle positioning over time. Boston Children’s Hospital+1

4) Scar management (massage, silicone, pressure, OT guidance). Scars can tighten and limit motion. Purpose: softer, flatter scars. Mechanism: controlled pressure and remodeling support during healing. Boston Children’s Hospital+1

5) Range-of-motion home program (therapist-taught). Short daily practice helps maintain gains after surgery. Purpose: prevent stiffness. Mechanism: repeated safe motion keeps tissues flexible. Boston Children’s Hospital+1

6) Strength and grip training (age-appropriate). After separation, fingers may feel weak. Purpose: stronger grasp/pinch. Mechanism: progressive resistance and functional play tasks. Shriners Children’s+1

7) Sensory re-education and desensitization. After surgery, skin sensitivity can change. Purpose: comfort and better hand use. Mechanism: graded touch exposure and texture practice. Boston Children’s Hospital+1

8) Adaptive equipment for daily life. Tools like special grips, Velcro shoes, and modified utensils reduce frustration. Purpose: independence. Mechanism: easier mechanics requiring less fine pinch. Boston Children’s Hospital+1

9) School accommodations. Extra time for writing, keyboard use, or OT at school can protect learning. Purpose: equal access. Mechanism: reducing hand load while keeping skill growth. Shriners Children’s+1

10) Psychological support (confidence + coping skills). Visible limb differences can affect self-esteem. Purpose: mental well-being. Mechanism: coping strategies, family support, and social skills practice. Orpha.net+1

11) Genetic counseling for the family. CLSS is often autosomal recessive, so recurrence risk can be 25% for each pregnancy when both parents are carriers. Purpose: informed planning. Mechanism: inheritance education + testing options. Orpha.net+1

12) Kidney monitoring (if kidney anomalies exist). Some people have renal agenesis/hypoplasia and need follow-up. Purpose: protect kidney function early. Mechanism: labs/imaging + nephrology care. NCBI+1

13) Safe sports and injury prevention coaching. Hands may be vulnerable during contact sports. Purpose: avoid fractures and overuse pain. Mechanism: protective gear + safer techniques. NCBI+1

14) Ergonomic training (how to hold tools safely). Purpose: reduce strain and pain. Mechanism: changing angles, using larger grips, and frequent breaks. handsurgeryresource.net+1

15) Staged goal planning (multiple surgeries may be needed). Complex syndactyly often needs careful timing and sometimes more than one operation. Purpose: safer healing and better function. Mechanism: step-by-step reconstruction plan. eMedicine+1

16) Family training for wound/cast care. Purpose: prevent infection and skin breakdown. Mechanism: clean care routines, watching for fever/redness, and protecting the hand. Boston Children’s Hospital+1

17) Speech/feeding therapy if craniofacial issues exist. Some CLSS cases include facial differences; therapy may help if speech/feeding is affected. Purpose: clear speech and safe eating. Mechanism: guided exercises and technique training. NCBI+1

18) Regular eye/ear screening (general developmental care). Purpose: catch treatable issues early. Mechanism: routine pediatric screening and referrals. Orpha.net+1

19) Pain coping skills (non-drug). Heat/ice guidance, relaxation breathing, and pacing can help mild pain. Purpose: comfort. Mechanism: calming the stress response and reducing overuse. NCBI+1

20) Peer/community support. Meeting others with limb differences can reduce isolation. Purpose: emotional strength. Mechanism: shared strategies and belonging. Orpha.net+1

---

Drug treatments

1) OFIRMEV (IV acetaminophen). Used for short-term pain/fever, often around surgery. Class: analgesic/antipyretic. Typical timing: peri-operative. Mechanism: central pain/fever pathway effects. Key risks: liver toxicity if total acetaminophen from all products is too high. FDA Access Data+1

2) CALDOLOR (IV ibuprofen). Helps pain/inflammation/fever in hospital settings. Class: NSAID. Timing: short-term acute pain. Mechanism: COX inhibition → less prostaglandins. Key risks: bleeding risk, kidney strain, stomach irritation, cardiovascular warnings. FDA Access Data+1

3) Ketorolac injection. A strong NSAID often used briefly after surgery. Class: NSAID. Timing: very short course. Mechanism: COX inhibition. Key risks: bleeding, kidney injury, stomach ulcers—so strict duration limits are used. FDA Access Data

4) Morphine sulfate injection. For severe acute pain (usually monitored in a hospital). Class: opioid agonist. Timing: acute severe pain. Mechanism: opioid receptor activation reduces pain signaling. Key risks: breathing suppression, sedation, dependence, constipation. FDA Access Data+1

5) OXYCONTIN (oxycodone ER). For severe, persistent pain in carefully selected patients; not typical for routine post-op use in children and requires strict specialist oversight. Class: opioid. Timing: extended-release schedule. Mechanism: opioid receptor activation. Key risks: addiction, overdose, respiratory depression. FDA Access Data+1

6) NORCO (hydrocodone/acetaminophen). Short-term moderate pain option when prescribed. Class: opioid + analgesic combo. Timing: as directed for acute pain. Mechanism: opioid effect + acetaminophen effect. Key risks: dependence and acetaminophen liver toxicity if combined with other acetaminophen products. FDA Access Data+1

7) ULTRAM (tramadol). Sometimes used for pain, but has important safety limits (seizure risk and drug interactions) and is not appropriate for many children. Class: opioid-like analgesic. Mechanism: opioid activity + monoamine effects. Key risks: breathing suppression, serotonin syndrome risk with some meds. FDA Access Data+1

8) NEURONTIN (gabapentin). Can be used for nerve-type pain in some situations. Class: anticonvulsant/neuropathic pain agent. Timing: scheduled dosing if chosen. Mechanism: modifies calcium channel signaling to reduce excitability. Key risks: sleepiness, dizziness, behavior changes in some people. FDA Access Data

9) ZOFRAN injection (ondansetron). Helps prevent nausea/vomiting after anesthesia or strong pain medicines. Class: antiemetic (5-HT3 blocker). Timing: peri-operative. Mechanism: blocks serotonin signals in vomiting pathways. Key risks: QT prolongation in some patients. FDA Access Data+1

10) CEFAZOLIN injection. Common antibiotic for surgical prophylaxis or specific infections. Class: cephalosporin antibiotic. Timing: before incision or for infection treatment. Mechanism: blocks bacterial cell wall building. Key risks: allergy, diarrhea, C. difficile risk. FDA Access Data+1

11) AUGMENTIN (amoxicillin/clavulanate). Treats many skin/soft-tissue and other bacterial infections when indicated. Class: penicillin antibiotic + beta-lactamase inhibitor. Timing: set course. Mechanism: kills bacteria + protects amoxicillin from breakdown. Key risks: diarrhea, allergy, liver enzyme issues in some. FDA Access Data+1

12) CLEOCIN (clindamycin). Option for certain skin/bone infections or penicillin allergy cases, depending on culture guidance. Class: lincosamide antibiotic. Timing: course-based. Mechanism: blocks bacterial protein making. Key risks: higher C. difficile diarrhea risk. FDA Access Data+1

13) KEFLEX (cephalexin). Oral antibiotic for some skin/soft tissue infections when bacteria are susceptible. Class: cephalosporin antibiotic. Timing: course-based. Mechanism: blocks bacterial cell wall synthesis. Key risks: allergy and stomach upset. FDA Access Data+1

14) CELEBREX (celecoxib). NSAID for pain/inflammation in selected cases. Class: COX-2 selective NSAID. Timing: short-term or longer if a doctor decides. Mechanism: reduces inflammatory prostaglandins. Key risks: cardiovascular and GI warnings still exist. FDA Access Data

15) NAPROSYN (naproxen). NSAID for pain/inflammation; sometimes used for musculoskeletal pain. Class: NSAID. Timing: scheduled as prescribed. Mechanism: COX inhibition. Key risks: stomach bleeding, kidney strain, cardiovascular risk. FDA Access Data

16) NAPRELAN (naproxen sodium ER). Extended-release naproxen for selected chronic pain situations (doctor-decided). Class: NSAID. Timing: extended-release schedule. Mechanism: COX inhibition. Key risks: similar NSAID warnings (GI/kidney/cardiac). FDA Access Data

17) NARCAN (naloxone nasal spray). Emergency rescue medicine for opioid overdose risk in homes where opioids are prescribed. Class: opioid antagonist. Timing: emergency only. Mechanism: reverses opioid effects at receptors. Key risks: sudden withdrawal symptoms. FDA Access Data+1

18) Naloxone injection (generic). Same purpose as above, used by trained medical staff or emergency responders. Class: opioid antagonist. Timing: emergency. Mechanism: opioid receptor blockade. Key risks: withdrawal symptoms. FDA Access Data+1

19) EVZIO (naloxone auto-injector). Another naloxone formulation designed for rapid emergency use (availability varies). Class: opioid antagonist. Timing: emergency. Mechanism: opioid receptor blockade. Key risks: withdrawal symptoms. FDA Access Data

20) ZIMHI (naloxone prefilled syringe). Another naloxone product used in emergencies by trained people. Class: opioid antagonist. Timing: emergency. Mechanism: opioid receptor blockade. Key risks: withdrawal symptoms. FDA Access Data

---

Dietary molecular supplements

1) Vitamin D. Supports bone and muscle health, which matters during growth and rehabilitation. Dose depends on age, blood levels, and diet. Mechanism: improves calcium absorption and bone mineral balance. Too much can be harmful, so testing may be needed. APIM+1

2) Calcium. Helps build strong bones and teeth; useful if dietary calcium is low. Dose depends on age and food intake. Mechanism: bone mineral structure and nerve/muscle signaling. Too much can cause kidney stones in some people. Office of Dietary Supplements+1

3) Vitamin C. Helps collagen formation and tissue repair; some studies show benefit in certain wound settings. Dose depends on diet and medical need. Mechanism: collagen support + antioxidant effects. Too much can cause stomach upset. Digital Media+1

4) Zinc. Important for immune function and wound repair; best used when a deficiency risk exists. Dose depends on age and diet. Mechanism: enzyme activity in healing and immunity. Too much zinc can reduce copper absorption. Office of Dietary Supplements+1

5) Omega-3 fatty acids. Can support overall health and inflammation balance, mainly through diet (fish) or supplements if advised. Dose varies. Mechanism: changes inflammatory mediator production. High doses may increase bleeding risk in some settings. Office of Dietary Supplements

6) Iron (only if deficient). Helps oxygen delivery through hemoglobin; low iron can worsen tiredness and slow recovery. Dose depends on lab tests. Mechanism: restores hemoglobin/myoglobin function. Too much iron is dangerous, so testing is key. Office of Dietary Supplements+1

7) Folate. Supports DNA and cell division, important for growth and blood health. Dose depends on diet and medical advice. Mechanism: folate-dependent DNA synthesis. High doses can mask B12 deficiency. Office of Dietary Supplements+1

8) Vitamin B12. Supports nerve and blood cell health; useful if diet is low or absorption is poor. Dose depends on cause of deficiency. Mechanism: DNA formation and nerve maintenance. Office of Dietary Supplements+1

9) Magnesium. Supports muscle and nerve function and many enzyme systems; best when intake is low. Dose varies. Mechanism: enzyme cofactor for protein synthesis and nerve/muscle signaling. Excess from supplements can cause diarrhea. Office of Dietary Supplements+1

10) Probiotics (situation-specific). Sometimes considered during/after antibiotics for gut health, but strain and safety matter. Dose varies by product. Mechanism: supports gut microbiome balance. In immunocompromised people, probiotics may be risky. Office of Dietary Supplements+1

---

Medicines for immunity booster / regenerative / stem-cell related

CLSS does not usually mean “weak immunity,” and there is no proven stem-cell drug that corrects CLSS limb development after birth; the options below are only for special medical situations decided by specialists. NCBI+1

1) IVIG (immune globulin IV). Used for certain immune deficiencies, not for CLSS itself. Dose is weight-based and diagnosis-based. Mechanism: provides protective antibodies. Risks include infusion reactions and rare clot/kidney issues. FDA Access Data+1

2) Filgrastim (NEUPOGEN). Helps bone marrow make neutrophils in specific conditions (not CLSS routine). Dose is weight-based. Mechanism: G-CSF stimulation of neutrophil production. Risks include bone pain and spleen enlargement warnings. FDA Access Data

3) Pegfilgrastim (NEULASTA). Longer-acting G-CSF for selected patients (usually oncology). Dose depends on protocol. Mechanism: prolonged neutrophil stimulation. Risks include bone pain and rare serious reactions. FDA Access Data

4) Plerixafor (MOZOBIL). Helps move blood stem cells into the bloodstream before collection for transplant. Dose is weight-based. Mechanism: blocks CXCR4 to mobilize stem cells. Not a CLSS repair therapy. FDA Access Data

5) Epoetin alfa (EPOGEN/PROCRIT). Boosts red blood cell production in selected anemias. Dose depends on labs and cause. Mechanism: erythropoietin receptor stimulation. Risks include clot and blood pressure issues. FDA Access Data+1

6) Becaplermin gel (REGRANEX). A topical growth-factor gel for specific chronic wounds (mainly diabetic ulcers). Not a CLSS limb-forming treatment. Mechanism: PDGF supports local healing signals. Risks/warnings exist and careful use is required. FDA Access Data

---

Surgeries (procedures and why they are done)

1) Syndactyly release (finger/toe separation). Done to improve hand function, growth, and hygiene, especially when fingers are tightly fused. It may involve skin grafts and staged operations for complex cases. eMedicine+1

2) Web-space reconstruction (Z-plasty/flaps). Done to create a deeper, stable web space so fingers can spread and pinch better. NCBI+1

3) Polydactyly excision or ray correction (if extra/dysplastic digits exist). Done to improve alignment and function or to fit shoes/gloves more easily. Shriners Children’s+1

4) Bone realignment/osteotomy (selected cases). Done when bone shape or alignment blocks function. Goal is better positioning for grasp and daily tasks. NCBI+1

5) Surgery for radioulnar synostosis (selected cases). Not everyone needs it; it may be done when fixed forearm rotation causes major function problems. Therapy is still essential after surgery. NCBI+1

---

Preventions

1) Prevent infection after surgery by following wound/cast instructions and seeking care early for fever or spreading redness. Boston Children’s Hospital+1
2) Prevent stiffness with therapist-approved motion and splint use. Boston Children’s Hospital+1
3) Prevent scar tightening with scar care plans from OT. Boston Children’s Hospital+1
4) Prevent overuse pain using pacing and ergonomic grips. handsurgeryresource.net+1
5) Prevent falls/hand injuries with protective gear in risky activities. NCBI+1
6) Prevent kidney damage (if kidney anomalies exist) with routine monitoring and avoiding dehydration. NCBI+1
7) Prevent medicine harm by avoiding “double NSAIDs” or multiple acetaminophen products at once (doctor/pharmacist can check). FDA Access Data+1
8) Prevent opioid accidents by safe storage and having naloxone if opioids are prescribed. FDA Access Data+1
9) Prevent school setbacks with early accommodations (keyboard, extra time, OT support). Shriners Children’s+1
10) Prevent repeated surprise cases in families with genetic counseling and carrier testing when appropriate. Orpha.net+1

---

When to see a doctor (urgent and non-urgent)

See a doctor urgently for trouble breathing, blue lips, extreme sleepiness after pain medicines, severe allergic swelling/rash, uncontrolled bleeding, or a very painful swollen hand after surgery. FDA Access Data+1

See a doctor soon for fever, bad-smelling wound drainage, worsening redness, new numbness, loss of finger motion, or new urinary problems (pain, swelling, low urine, recurrent UTIs), especially if CLSS includes kidney anomalies. Boston Children’s Hospital+1

---

What to eat and what to avoid

1) Eat enough protein (eggs, fish, beans, dairy) to support tissue repair and strength. ScienceDirect+1
2) Eat vitamin-C foods (citrus, guava, peppers) for collagen support. PMC+1
3) Include zinc foods (meat, lentils, nuts) if your diet is low. Office of Dietary Supplements+1
4) Include calcium + vitamin D foods (milk, yogurt, small fish with bones) for bone health. Office of Dietary Supplements+1
5) Choose iron foods if needed (meat, beans, spinach) and confirm deficiency with tests first. Office of Dietary Supplements+1
6) Add healthy fats (fish, olive oil, nuts) for overall health; supplements only if advised. Office of Dietary Supplements
7) Drink enough water, especially if kidney follow-up is needed. NCBI+1
8) Avoid smoking/vaping exposure because it can slow healing and harms health. ScienceDirect
9) Avoid “mega-dose” supplements unless prescribed—too much can harm (iron, zinc, vitamin D). Office of Dietary Supplements+1
10) Avoid mixing pain medicines (example: two NSAIDs together) unless a clinician says so. FDA Access Data+1

---

FAQs

1) Is CLSS curable? There is no gene-correcting cure today; care aims to improve function and prevent problems. Orpha.net+1

2) What causes CLSS? It is usually due to inherited gene changes affecting limb development pathways. NCBI+1

3) Is it contagious? No, it is genetic and not an infection. NCBI

4) Which body parts are mainly affected? Hands and feet are most affected; some people also have kidney anomalies. NCBI+1

5) Will my child need surgery? Many do, especially for severe syndactyly, but timing and need depend on function. eMedicine+1

6) Why is therapy needed after surgery? Therapy helps prevent stiffness/scar tightening and teaches new movement patterns. Shriners Children’s+1

7) Can toes be left untreated? Sometimes, if function is fine; surgery may be for function or sometimes appearance. NCBI

8) What is radioulnar synostosis? A bony connection that limits forearm rotation; some people adapt without surgery. NCBI+1

9) Does CLSS affect intelligence? CLSS is mainly a physical malformation syndrome; learning support is based on the individual child’s needs. Orpha.net+1

10) Can CLSS be prevented? You cannot “prevent” the gene change, but genetic counseling helps families understand recurrence risk. Orpha.net+1

11) Are there CLSS-specific medicines? No FDA-approved medicine corrects CLSS; medicines are supportive (pain, infection, nausea). Orpha.net+1

12) Are supplements always needed? Not always—use supplements mainly when diet is low or a deficiency is proven. Office of Dietary Supplements+1

13) Why are kidney checks important? Kidney anomalies can occur, and early monitoring helps protect long-term health. NCBI+1

14) What’s the long-term outlook? Many people do well with planned surgery, therapy, and adaptive strategies, but needs vary widely. Orpha.net+1

15) What kind of doctors are involved? Hand/orthopedic surgeons, OT/PT, genetics, and sometimes nephrology (kidney). 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: December 16, 2025.