Association Between Thumb Hypoplasia, Radial Longitudinal Deficiency, and Radial Polydactyly

Area of Science:

• Developmental Biology
• Orthopedic Surgery
• Genetics

Background:

• Sonic hedgehog protein expression is linked to radial longitudinal deficiency (RLD) and radial polydactyly in animal models.
• Understanding the co-occurrence and clinical presentation of these conditions in humans is crucial for diagnosis and management.

Purpose of the Study:

• To investigate the co-occurrence of thumb hypoplasia/RLD and radial polydactyly in a large patient registry.
• To analyze the clinical presentations and associated comorbidities in patients with both conditions.

Main Methods:

• Querying the Congenital Upper Limb Differences (CoULD) registry for patients with contralateral thumb hypoplasia/RLD and radial polydactyly (Oberg-Manske-Tonkin classification).
• Collecting demographic data, medical and musculoskeletal comorbidities, radiographs, and clinical images.

Main Results:

• Ten patients with contralateral thumb hypoplasia/RLD and radial polydactyly were identified.
• A wide range of classifications for both thumb hypoplasia and radial polydactyly were observed.
• Four patients had syndrome diagnoses, four had medical comorbidities, and three had other orthopedic conditions.

Conclusions:

• Co-occurrence of thumb hypoplasia/RLD and radial polydactyly showed no clear association in severity.
• Minimal forearm involvement was noted, impacting hand development timing.
• High variability in presentations, including syndromic conditions and comorbidities, necessitates thorough clinical examination and potential further medical testing.