Limb reduction defects in Emilia Romagna, Italy: epidemiological and genetic study in 173 109 consecutive births

Epidemiological and genetic variables in limb reduction defects (LRD) were analysed during the years 1978 to 1987 in a case control study in Emilia Romagna, northern Italy. During the observation period, 83 neonates out of 173 109 consecutive births had LRD (4-8 per 10 000). Cases were divided into five subgroups: transverse, intercalary, longitudinal, split, and multiple types of LRD. Of all cases, 64% were upper limb, 21% lower limb, and 15% both. Coexisting non-limb malformations were found in 10 cases (12%), five with recognised syndromes and five with other associated defects. About 7-2% of first degree relatives had defects involving the skeletal system. In two cases the mother had the same type of LRD (a split). No recurrence among sibs was observed. Risk factors correlated with LRD were found to be low birth weight (2500 g or less), vaginal bleeding, and threatened abortion.