Polydactyly - observation

Description

• A patient with polydactyly will have an extra digit or digits. Joints, tendons and ligaments may also be affected. Polydactyly may severely decrease hand function, especially if it involves the thumb. Parents or guardians may seek operative treatment for functional and/or cosmetic reasons.¹
• Polydactyly is primarily diagnosed by observation. It is also possible to diagnose polydactyly through ultrasound, at 14 weeks of pregnancy or later.
• Polydactyly is often syndromic; for example, it can be related to Down’s syndrome or Poland syndrome.²

Pathophysiology

• Polydactyly can be inherited as an autosomal dominant or recessive mutation. Autosomal dominant phenotypes are usually less severe.²

Instructions

1. Diagnose polydactyly primarily through observation. It may occur in any finger, but is not usually bilateral. 
2. Check whether polydactyly of the central fingers is hidden within a syndactyly.³
3. Ask the parent or guardian if the patient has any difficulties with hand function in daily activities. 
4. Confirm the diagnosis by taking a history of the patient. 
5. Examine the contralateral hand.

Variations

• Polydactyly may be hidden within a syndactyly, which is called synpolydactyly.

Related Signs and Tests

• Ultrasound, starting at 14 weeks of pregnancy
• Radiographs

Diagnostic Performance Characteristics

• (NA)

Differential Diagnoses

• Clinodactyly
• Camptodactyly
• Synpolydactyly
• Dermatologic manifestations of Down’s syndrome
• Poland syndrome²