Overview
Mirror-image polydactyly is a very rare condition present at birth where a person has extra fingers or toes that are arranged in a mirror-image pattern. This means the hand or foot looks like it has two identical halves facing each other, like a reflection in a mirror. Instead of the normal arrangement of fingers — with a thumb on one side and a little finger on the other — both sides of the hand may look the same, often with multiple thumbs or multiple little fingers. The feet can be affected in a similar way. This condition is also sometimes called 'mirror hand,' 'ulnar dimelia' (when the forearm bone called the ulna is duplicated), or 'Laurin-Sandrow syndrome' when it involves both the hands and feet together with other limb differences. The condition mainly affects the limbs. In the hands, there is often no thumb in the usual sense, and instead there may be six to eight fingers arranged symmetrically. The forearm may also have two ulna bones instead of the normal one ulna and one radius. In the feet, extra toes are arranged in a similar mirror pattern. Some people have only hand involvement, some only foot involvement, and others have both. In rare cases, the condition is part of a broader syndrome affecting other parts of the body. Treatment focuses on surgery to improve the function and appearance of the affected hand or foot. The goal is to create a hand that can grip and perform everyday tasks as well as possible. With skilled surgical care and rehabilitation, many people with this condition can lead full and active lives. Early evaluation by a specialist is important to plan the best approach for each individual.
Key symptoms:
Extra fingers on one or both hands, arranged in a mirror-image patternExtra toes on one or both feet, arranged in a mirror-image patternAbsence of a normal thumb, replaced by mirror-image fingersDuplication of the ulna bone in the forearm (two ulna bones instead of one)Symmetrical appearance of the hand or foot, like two identical halvesReduced ability to grip or pinch objects due to abnormal hand structureAbnormal wrist shape or limited wrist movementFoot deformity affecting walking or shoe fittingIn some cases, involvement of both hands and both feet
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 Mirror-image polydactyly.
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View all trials with filters →No actively recruiting trials found for Mirror-image polydactyly at this time.
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Specialists
View all specialists →No specialists are currently listed for Mirror-image polydactyly.
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 Mirror-image polydactyly.
Community
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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 is the best timing for surgery, and how many operations might my child need?,What level of hand or foot function can we realistically expect after treatment?,Should our family have genetic testing, and what does it mean for future pregnancies?,What type of therapy will my child need after surgery, and for how long?,Are there any specialists or centers with specific experience treating mirror-image polydactyly?,Are there any support groups or other families we can connect with?,What school or daily life accommodations should we put in place?
Common questions about Mirror-image polydactyly
What is Mirror-image polydactyly?
Mirror-image polydactyly is a very rare condition present at birth where a person has extra fingers or toes that are arranged in a mirror-image pattern. This means the hand or foot looks like it has two identical halves facing each other, like a reflection in a mirror. Instead of the normal arrangement of fingers — with a thumb on one side and a little finger on the other — both sides of the hand may look the same, often with multiple thumbs or multiple little fingers. The feet can be affected in a similar way. This condition is also sometimes called 'mirror hand,' 'ulnar dimelia' (when the fo
At what age does Mirror-image polydactyly typically begin?
Typical onset of Mirror-image polydactyly is neonatal. Age of onset can vary across affected individuals.