Familial clustering of 8 minor anomalies

Abstract

We have carried out a surface examination on 5,500 newborn infants. The incidence of eight minor anomalies among the first 3,000 infants has been determined for both black (B) and white (W) newborns without major anomalies: simian crease (B 2.3%, W 3.3%), syndactyly toes 2-3 (B 0.0, W 1.1), preauricular sinus (B 1.2, W 0.7), preauricular tag (B 0.6, W 0.8), epicanthal fold (B 0.4, W 0.5), Darwinian point (B 0.1 W 1.4), Darwinian tubercle (B 0.1, W 0.5) and clinodactyly (B 4.3, W 10). Only for clinodactyly could varying degrees of severity be measured.All mothers and about 8% of fathers were examined for minor anomalies of the hands and face. Only Darwinian tubercle was more common in the parents than in the infants. Clinodactyly and epicanthal folds were much less common in adults. The rate of recurrence of preauricular sinus and tag and simian crease among the offspring of affected parents was clearly greater than the incidence in the general population. Data on the rate of recurrence of the other anomalies is inconclusive in this sample.The concordance rate for these 8 minor anomalies was determined for 17 sets of MZ twins and 19 sets of DZ twins. There was no significant difference, but the sample size was too small.This study suggests racial and familial clustering of minor anomalies. A mode of inheritance may be evident when the evaluation of the total sample of 8,000 infants is completed.