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Polydactyly of foot in Child
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Polydactyly of foot in Child

Contributors: Taylor Jones, Ryan Snowden MD, John T. Finnell MD, Benedict F. DiGiovanni MD, FAOA, FAAOS
Other Resources UpToDate PubMed

Synopsis

Causes / typical injury mechanism: Polydactyly may be due to an isolated trait or as part of a genetic syndrome. Multiple gene loci have been linked to the development of polydactyly, including:
  • GLI3 (associated with Greig cephalopolysyndactyly syndrome)
  • SHH
  • FGF
  • ALX4
  • 5'HoxD
  • ZNF141
  • MIPOL1
  • IQCE
  • PITX1
Classic history and presentation: Polydactyly presents in infancy, or patients may present later in childhood when shoe fitting becomes a concern. It may appear in isolation or with other birth defects.

Prevalence:
  • Represents 45% of congenital foot anomalies.
  • Incidence of 1.7 per 1000 live births.
  • No sex predilection.
  • Postaxial – Most common, constituting 80% of duplications.
  • Preaxial – 15% of duplications.
  • Central – 5% of duplications.
Risk factors:
  • About 30% of patients with isolated polydactyly have a positive family history.
  • Syndromes that feature polydactyly include Ellis-van Creveld syndrome, trisomy 13 syndrome, tibial hemimelia, trisomy 21 (Down syndrome), and Greig cephalopolysyndactyly syndrome.
  • Patients of African descent have a higher incidence rate of 3.6-13.9 per 1000 live births.
Pathophysiology: Two theories may explain the development of polydactyly: a disorder in the programmed cell death during fetal limb development, or the genetic mutations of some gene loci.

Grade / classification system:
  • Classified according to its location as preaxial (first ray), central (middle rays), or postaxial (fifth ray).
  • Temtamy and McKusick classification – This classifies cases as preaxial, postaxial, or complicated and is used by geneticists.
  • Venn-Watson (V-W) classification – Based on the shape of the associated metatarsal bone.
    • Normal metatarsal with distal duplication
    • Block metatarsal
    • Y-shaped metatarsal
    • T-shaped metatarsal
    • Normal metatarsal shaft with a wide head
    • Ray duplication
  • Watanabe-Fujita classification of medial ray polydactyly.
    • Tarsal
    • Metatarsal
    • Proximal phalangeal
    • Distal phalangeal

Codes

ICD10CM:
Q69.2 – Accessory toe(s)

SNOMEDCT:
62218008 – Polydactyly of foot

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Last Reviewed:06/14/2024
Last Updated:07/29/2024
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Polydactyly of foot in Child
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