Upper limb deficiencies and associated malformations: a population-based study.

As part of an ongoing analysis of limb deficiencies occurring among 1,213,913 consecutive livebirths in British Columbia during the years 1952-1984, all cases with deficiencies of the upper limbs were analysed with a view to identifying associated patterns of anomalies. This analysis resulted in seven subgroups. For each subgroup, incidence figures for cases with and without additional anomalies were calculated separately. The proportion of cases with additional anomalies varied markedly by subgroup. For example, 89% of cases with longitudinal defects of the radius had additional malformations, while only 28% of cases with transverse defects of the radius had other organ anomalies (chi 2 = 40.55; P < 0.001, one degree of freedom). A preponderance of males was found among the cases with associated defects, particularly in the group with longitudinal defects of the radius (28 males, 14 females; chi 2 = 14.10; P < 0.001). Clustering of specific patterns of associated malformations is described within subgroups.