A multidisciplinary review of triphalangeal thumb

J Hand Surg Eur Vol. 2019 Jan;44(1):59-68. doi: 10.1177/1753193418803521. Epub 2018 Oct 14.


Despite being a rare congenital limb anomaly, triphalangeal thumb is a subject of research in various scientific fields, providing new insights in clinical research and evolutionary biology. The findings of triphalangeal thumb can be predictive for other congenital anomalies as part of an underlying syndrome. Furthermore, triphalangeal thumb is still being used as a model in molecular genetics to study gene regulation by long-range regulatory elements. We present a review that summarizes a number of scientifically relevant topics that involve the triphalangeal thumb phenotype. Future initiatives involving multidisciplinary teams collaborating in the field of triphalangeal thumb research can lead to a better understanding of the pathogenesis and molecular mechanisms of this condition as well as other congenital upper limb anomalies.

Keywords: Triphalangeal thumb; congenital limb deformities; genetic enhancer elements; hedgehog protein; polydactyly.

Publication types

  • Review

MeSH terms

  • Abnormalities, Multiple / epidemiology
  • Fingers / embryology
  • Gene Duplication / genetics
  • Hand Deformities, Congenital / epidemiology
  • Hand Deformities, Congenital / genetics*
  • Hedgehog Proteins / physiology
  • Humans
  • Nerve Tissue Proteins / physiology
  • Phenotype
  • Point Mutation
  • Thumb / abnormalities*
  • Zinc Finger Protein Gli3 / physiology


  • GLI3 protein, human
  • Hedgehog Proteins
  • Nerve Tissue Proteins
  • SHH protein, human
  • Zinc Finger Protein Gli3

Supplementary concepts

  • Triphalangeal Thumb