Overview
Crossed polysyndactyly is a very rare birth defect that affects the fingers and toes. In this condition, a person is born with extra fingers (polydactyly) on one hand or both hands and fused or webbed toes (syndactyly) on one or both feet, or vice versa — meaning the type of abnormality 'crosses' between the hands and feet rather than being the same in both. For example, a person might have extra fingers on their hands but webbed toes on their feet. The condition is present at birth and is typically noticed right away during a newborn examination. Crossed polysyndactyly can vary in severity. Some individuals may have mild webbing between toes or a small extra finger, while others may have more complex hand or foot differences that affect function. The condition primarily affects the structure of the hands and feet and does not usually involve other organ systems or intellectual development. Treatment is mainly surgical. Depending on the severity, surgery may be performed to remove extra fingers, separate fused toes, or improve the function and appearance of the hands and feet. Occupational therapy and physical therapy may also be recommended after surgery to help with hand function and mobility. With appropriate treatment, most individuals with crossed polysyndactyly can lead normal, active lives. Early evaluation by a hand surgeon or orthopedic specialist experienced in limb differences is important for planning the best approach to care.
Key symptoms:
Extra fingers on one or both handsWebbed or fused toes on one or both feetExtra toes on one or both feetWebbed or fused fingers on one or both handsDifferent types of hand and foot abnormalities on opposite limbsDifficulty gripping or grasping objects if hands are affectedDifficulty with walking or shoe fitting if feet are affectedAbnormal appearance of fingers or toes
Clinical phenotype terms (11)— hover any for plain English
Autosomal dominant
Passed on from just one parent; each child has about a 50% chance of inheriting it
Neonatal
Begins at or shortly after birth (first 4 weeks)
Treatments
No FDA-approved treatments are currently listed for Crossed polysyndactyly.
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Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Crossed polysyndactyly.
Community
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Caregiver Resources
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Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.How severe is my child's condition, and which fingers or toes are affected?,When is the best time to have corrective surgery?,How many surgeries might be needed, and what are the expected outcomes?,Will my child need occupational or physical therapy after surgery?,Is genetic testing recommended for our family?,What is the chance that future children could have the same condition?,Are there any long-term complications we should watch for?
Common questions about Crossed polysyndactyly
What is Crossed polysyndactyly?
Crossed polysyndactyly is a very rare birth defect that affects the fingers and toes. In this condition, a person is born with extra fingers (polydactyly) on one hand or both hands and fused or webbed toes (syndactyly) on one or both feet, or vice versa — meaning the type of abnormality 'crosses' between the hands and feet rather than being the same in both. For example, a person might have extra fingers on their hands but webbed toes on their feet. The condition is present at birth and is typically noticed right away during a newborn examination. Crossed polysyndactyly can vary in severity.
How is Crossed polysyndactyly inherited?
Crossed polysyndactyly follows a autosomal dominant inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Crossed polysyndactyly typically begin?
Typical onset of Crossed polysyndactyly is neonatal. Age of onset can vary across affected individuals.
Which specialists treat Crossed polysyndactyly?
5 specialists and care centers treating Crossed polysyndactyly are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.