Significance of the single umbilical artery. A clinical, radiological, chromosomal, and dermatoglyphic study.

A single umbilical artery is present in about 1% of all singletons. It is associated with a wide range of congenital malformations. Chromosomal analysis of our surviving cases gave normal results. Dermatoglyphic patterns were normal, except that the boys showed a three- to fourfold increase in the number of the radial loops on the fingers, and a lowering of the total finger ridge count. Evidence favouring a common non-genetic cause for both a single umbilical artery and the associated malformations is discussed.