polydactylies

Polydactyly is defined as duplication of a finger or part of it. It occurs as an isolated malformation, in association with other malformations of the hands and/or feet, or as a part of a syndrome. Sporadic as well as familial occurrence have been described. In the latter it is usually inherited as an autosomal dominant trait. The prevalence of polydactyly with or without an associated malformation varies between 5 and 17 per 10,000 live births.

Types

 preaxial polydactyly

• preaxial polydactylytype 1: thumb polydactyly
• preaxial polydactylytype 2: polydactyly of a triphalangeal thumb
• preaxial polydactylytype 3: polydactyly of an index finger
• preaxial polydactyly type 4: polysyndactyly

 central polydactyly (medial ray)
 postaxial polydactyly (lateral ray)

Etiology

 isolated polydactyly (postaxial hexadactyly ++)
 syndromal polydactyly (in malformative syndromes)

• postaxial polydatyly
  • Jeune syndrome (infantile thoracic dystrophy)
  • short rib-polydactyly syndromes
    • SRPS1: Saldino-Noonan syndrome (MIM.265530)
    • Ellis-van Creveld syndrome

• • Meckel syndrome (Meckel-Gruber syndrome)
  • Bardet-Bield syndrome
  • trisomy 13
  • pseudotrisomy 13 syndrome
  • polydactyly-hydrometrocolpos syndrome
  • Weyer acrofacial syndrome
  • Opitz C syndrome
  • Sugarman syndrome
  • Biechoud syndrome
  • Oliver syndrome
  • cleft palate and postaxial polysyndactyly syndromes (polydactyly-cleft palate association)
  • Pallister-Hall syndrome
  • Rutledge lethal multiple congenital anomaly syndrome (Smith-Lemli-Opitz syndrome type 2)
  • orofaciodigital syndromes
    • Varadi-Papp syndrome (OFDS6)

• syndromal preaxial poydactyly
  • Mohr syndrome
  • Majewski type of short rib
  • Towne syndrome
  • Varadi-Papp syndrome
  • acrocephalopolydactyly syndromes
    • dominant Pfeiffer syndrome
    • Carpenter syndrome
    • Sakati syndrome

References

 Lettice LA, Hill RE. Preaxial polydactyly: a model for defective long-range regulation in congenital abnormalities. Curr Opin Genet Dev. 2005 Jun;15(3):294-300. PMID: 15917205