CONGENITAL LIMB REDUCTION DEFECTS IN TWINS

The study relates to congenital limb reduction defects (CLRDs) in twin s from a 10-year-period (1975-1984) and is based on cases from the Hun garian Congenital Abnormality Registry. In order to clarify the respec tive contributions of genetic and environmental factors to CLRDs and t he role of causal factors in common with twinning, the occurrence of C LRDs in twins was studied. In eight multiple CLRD twin cases (i.e. tho se with additional non-limb malformations), one monozygous concordant and one semi-concordant twin pair was found, indicating that genetic f actors play a limited role in pathogenesis. There is no correlation be tween twinning and isolated CLRDs. Frequency of CLRDs in general was n o higher in twins than in all births, although there was a non-signifi cantly higher twinning rate in multiple CLRD cases. Twins with CLRDs w ere more often male? especially in multiple cases. Conclusion There ma y be a relationship between twinning and congenital abnormalities, but twinning is not a major factor contributing to CLRD cases.