Pre-axial polydactyly refers to polydactyly where the additional digit is towards the first digit of the hand (radial side) or foot (medially).
Pre-axial polydactyly is less common than post-axial polydactyly, with an estimated incidence of 1 in 7000.
Pre-axial polydactyly can be associated with:
- Down syndrome
- VATER association
- Holt-Oram syndrome
- Greig cephalopolysyndactyly syndrome
- Carpenter syndrome
- Laurin-Sandrow syndrome
- Fanconi anemia