Overview
Polydactyly of a biphalangeal thumb, unilateral, refers to having an extra thumb (or a duplicated thumb) on one hand, where the thumb involved has two bones (phalanges) instead of the usual two that normal thumbs have. In simple terms, this means one hand has a duplicated or split thumb, and the affected thumb has a specific bone structure. This condition is present at birth and is visible right away. It is important to note that this specific Orphanet entry is labeled as 'OBSOLETE,' meaning it has been retired or merged into a broader or updated classification of thumb polydactyly (also known as preaxial polydactyly or thumb duplication). Thumb duplication is one of the more common congenital hand differences. The extra thumb can range from a small skin tag to a fully formed extra digit. Treatment typically involves surgery to remove the extra thumb and reconstruct the remaining thumb so it works well and looks as normal as possible. Surgery is usually performed in infancy or early childhood. Outcomes are generally very good, especially when performed by an experienced pediatric hand surgeon. The condition does not usually affect overall health or lifespan, and most children go on to have excellent hand function after treatment.
Also known as:
Key symptoms:
Extra thumb on one handDuplicated or split thumb visible at birthThumb may appear wider or bifurcatedReduced grip strength in the affected handDifficulty with fine motor tasks using the affected handThe extra thumb may be smaller or less developed than the main thumbJoint instability in the affected thumbAltered appearance of the thumb nail
Variable
Can be inherited in different ways depending on the underlying gene
Neonatal
Begins at or shortly after birth (first 4 weeks)
Treatments
No FDA-approved treatments are currently listed for OBSOLETE: Polydactyly of a biphalangeal thumb, unilateral.
View clinical trials →Clinical Trials
View all trials with filters →No actively recruiting trials found for OBSOLETE: Polydactyly of a biphalangeal thumb, unilateral at this time.
New trials open frequently. Follow this disease to get notified.
Specialists
View all specialists →No specialists are currently listed for OBSOLETE: Polydactyly of a biphalangeal thumb, unilateral.
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 OBSOLETE: Polydactyly of a biphalangeal thumb, unilateral.
Community
No community posts yet. Be the first to share your experience with OBSOLETE: Polydactyly of a biphalangeal thumb, unilateral.
Start the conversation →Latest news about OBSOLETE: Polydactyly of a biphalangeal thumb, unilateral
No recent news articles for OBSOLETE: Polydactyly of a biphalangeal thumb, unilateral.
Follow this condition to be notified when news becomes available.
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
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.What type of thumb duplication does my child have, and how complex is it?,At what age do you recommend surgery, and what does the procedure involve?,What are the expected outcomes for hand function and appearance after surgery?,Will my child need occupational therapy after the operation?,Is there any chance this could be part of a genetic syndrome, and should we see a geneticist?,How many similar surgeries have you performed, and what results do you typically see?,Will my child need any follow-up surgeries as they grow?
Common questions about OBSOLETE: Polydactyly of a biphalangeal thumb, unilateral
What is OBSOLETE: Polydactyly of a biphalangeal thumb, unilateral?
Polydactyly of a biphalangeal thumb, unilateral, refers to having an extra thumb (or a duplicated thumb) on one hand, where the thumb involved has two bones (phalanges) instead of the usual two that normal thumbs have. In simple terms, this means one hand has a duplicated or split thumb, and the affected thumb has a specific bone structure. This condition is present at birth and is visible right away. It is important to note that this specific Orphanet entry is labeled as 'OBSOLETE,' meaning it has been retired or merged into a broader or updated classification of thumb polydactyly (also known
At what age does OBSOLETE: Polydactyly of a biphalangeal thumb, unilateral typically begin?
Typical onset of OBSOLETE: Polydactyly of a biphalangeal thumb, unilateral is neonatal. Age of onset can vary across affected individuals.