Symphalangism and Fourth Digit Hypophalangism

THE obvious nature of brachydactyly accounts for its interesting contribution to the history of medical genetics. It was the first anomaly in man reported to show dominant mendelian inheritance.1,2One of the few cases of an apparently homozygous autosomal dominant anomaly was reported in a family with mild brachydactyly in which intermarriage produced a child without fingers or toes who died at the age of one year.3Symphalangism (congenital fusion of the phalanges) is occasionally associated with brachydactyly. It, too, contributes to the history of human genetics. A family with symphalangism traced back 14 generations to the Earl of Shrewsbury (1453) of Shakespeare'sHenry VIrepresents one of the longest vertical histories of a human anomaly.4 Brachydactyly may be due to one of three anomalies: Brachyphalangy (short phalanges), Hypophalangy (absence of phalanges), or Brachymetacarpy (short metacarpals). It is transmitted as an autosomal dominant anomaly. The following is a report of a family