post axial polydactyly

Post-axial polydactyly refers to polydactyly where the additional digit is on the ulnar margin of the hand, or lateral to the 5(little) toe.

Epidemiology

Post-axial polydactyly is more common than preaxial polydactyly, with an estimated incidence of 1 in 3000 .

Associations

Post-axial polydactyly can be associated with:

• trisomy 13
• Bardet-Biedl syndrome
• Meckel Gruber syndrome
• McKusick-Kaufman syndrome
• following oral-facial-digital syndromes (OFDS)
  • oral-facial-digital syndrome (OFDS) type II - Mohr syndrome
  • oral-facial-digital syndrome (OFDS) type VI
• certain skeletal dysplasias
  • chondroectodermal dysplasia - Ellis-van Creveld syndrome
  • asphyxiating thoracic dysplasia - Jeune syndrome
• Smith Lemli Opitz syndrome
• certain short rib polydactyly syndromes: e.g types I and III

Pathology

The majority of cases are idiopathic. Associations with mutations to the GLI3 gene on chromosome 7 as well as a second locus mapped to chromosome 13 have been implicated in post-axial polydactyly .

Classification

Post-axial polydactyly has been defined by Temtamy and McKusick as:

• type A: additional digit at the MCP joint (or more proximally at the CMC joint)
• type B: small nubbin of non-functioning tissue or additional soft tissue on a pedicle

Or, you can use a separate three-part classification system:

• type I: nubbin or floating digit
• type II: duplications at the MCPJ
• type III: duplication of the entire ray

Siehe auch:

• Pätau-Syndrom
• Polydaktylie
• Meckel-Syndrom
• Ellis-van-Creveld-Syndrom
• Skelettdysplasie
• asphyxierende Thoraxdysplasie (Jeune-Syndrom)
• Bardet-Biedl syndrome
• Smith-Lemli-Opitz-Syndrom
• Kurzripp-Polydaktylie-Syndrome
• McKusick-Kaufman-Syndrom
• Dreigliedriger Daumen-Polysyndaktylie-Syndrom
• präaxiale Polydaktylie
• oral-facial-digital syndromes (OFDS)
• chondroectodermal dyplasia