Spontaneous abortion, sex ratio and facial cleft malformations

Abstract

In family and reproductive data combined from five treatment centers, relating to 861 index cases with cleft lip (with or without cleft palate, CL+/-P), maternally recognized spontaneous abortions were found to be significantly less frequent in sibships including two or more cases of CL+/-P than in sibships including only one case. In data relating to 379 index cases with cleft palate (CP), maternally recognized spontaneous abortions were reduced to a degree short of formal significant in sibships including two or more cases of CP by comparison with sibships including only one case of CP. The sex ratio among the sibs of parents of CL+/-P index cases was elevated when the index case was the only affected child and reduced when the index case had one or more affected sibs. Considered in combination with the results of other investigations, these findings indicate the existence of inherited factors reducing abortion frequency in the sibships of CL+/-P index cases. These factors appear to be unrelated to those for liability to CL+/-P.

PIP: Information on fetal wastage in the sibships of index cases is available for 4 of the series of facial cleft data which have been assembled for collaborative study in the Department of Medical Genetics, Montreal Children's Hospital. A series collected in the Department of Human Genetics, University of Newcastle upon Tyne was added. In family and reproductive data combined from these 5 treatment centers, relating to 861 index cases with cleft lip (with or without cleft palate), maternally recognized spontaneous abortions were found to be significantly less frequent in sibships including 2 or more cases of cleft palate than in sibships including only 1 case. In data relating to 379 index cases with cleft palate, maternally recognized spontaneous abortions were reduced to a degree short of formal significance in sibships including 2 or more cases of cleft palate by comparison with sibships including only 1 case of cleft palate. The sex ratio among the sibs of parents of cleft palate index cases was elevated when the index case was the only affected child and reduced when the index case had 1 or more affected sibs. Along with the results of other investigations, these findings indicate the existence of inherited factors reducing abortion frequency in the sibships of cleft palate index cases. These factors seem to be unrelated to those for liability to cleft palate.