A comparison of maternal age, sex ratio and associated anomalies among numerically aneuploid, structurally aneuploid and euploid holoprosencephaly.

During the period January 1987-July 2003, 59 cases of perinatally detected holoprosencephaly (HPE) with cytogenetic results were identified among 97,306 deliveries at Mackay Memorial Hospital. Among these 59 cases with HPE, 25 had euploidy, 27 had numerical aneuploidy, and 7 had structural aneuploidy. In the euploid cases, the male:female sex ratio was 0.39:1, whereas in the aneuploid cases, the ratio was 1:1. The mean (+/-SD) maternal ages for numerical aneuploidy, structural aneuploidy, and euploidy were 33.0 +/- 5.1 years, 27.9 +/- 2.1 years, and 27.8 +/- 5.0 years, respectively. The frequencies of associated major structural anomalies other than craniofacial defects in the cases with numerical aneuploidy, structural aneuploidy, and euploidy were 85.7%, 0%, and 16%, respectively. The present study of HPE suggests that a female excess appears only in the euploid cases, and advanced maternal age and structural anomalies are more commonly associated with the numerically aneuploid cases than the structurally aneuploid and euploid cases.