High incidence of central nervous system malformations associated with marked parental consanguinity in an Israeli Arab community

It is common among Israeli Arabs who live in villages to prefer consanguineous marriages, particularly among first cousins. In addition, such villages are populated by a few (< 20) original families, and inter-family/inter-village marriages are infrequent. The purpose of this study was to examine the incidence of congenital malformation of the central nervous system associated with such "consanguinity" in Taibe, a large Arab village, 30 km from Tel Aviv. Six hundred and ten families were prospectively ascertained through infants who were routinely seen in the local "Well Baby Clinics". A significant increase in the incidence of major malformations was noted in relation to the closeness of the parental relationship. For the index cases group, the prevalence of individuals with major malformations was 5.8% in the product of inter-village marriages, 8.3% in the intea-village non-related matings, 15.1% in the distant consanguineous group, and up to 15.8% in the progeny of first-cousin marriages (P < 0.001). Malformations of the central nervous system consisted of 1 3 to 1 2 of the total malformations in the consanguineous groups versus less than 1 5 in the non-consanguineous groups. The study demonstrates a marked high rate of consanguineous marriages, the effect of which leads to a marked increase in major malformations and especially those of the central nervous system. This requires a unique genetic counseling approach.