General Medical Information

Transverse Vaginal Septa and the McKusick-Kaufman Syndrome

Joe Leigh Simpson

Transverse vaginal septa occur at several locations and may be complete or incomplete. These septa usually are about 2 cm thick and located near the junction of the upper third and lower two thirds of the vagina. Septa may be present in the middle or lower third of the vagina. Perforations usually are central, but they may be eccentric in location. If no perforation is present, mucus and menstrual fluid cannot exit; thus, hydrocolpos or hydrometrocolpos develop. Pelvic organs otherwise usually are normal, although occasionally the uterus is bicornuate.

Vaginal septa presumably result from failure of urogenital sinus derivatives and müllerian duct derivatives to fuse or canalize. This explanation is deduced from location of the septa, namely at the predicted sites of urogenital sinus and müllerian fusion. Cranial surfaces of septa typically are lined by columnar (müllerian) epithelium, whereas caudal surfaces are lined by squamous epithelium (urogenital sinus invagination).

If transverse vaginal septa is associated with postaxial polydactyly and cardiac defects, the eponymous McKusick-Kaufman syndrome is applied. The original description of this syndrome and most cases reported since have been in the Amish. A single pleiotropic gene causing transverse vaginal septa could exist, or transverse vaginal septa could be genetically heterogeneous.

A single pleiotropic gene was the assumption underlying analysis of 54 Amish cases studied by Chitayat. Hydrometrocolpos was estimated to be present in 95% of female cases, polydactyly in 93%, and cardiovascular malformations in 9%. Individuals were observed with all three anomalies, various combinations of two anomalies, and only one anomaly. Stone estimated penetrance to be 70% for hydrometrocolpos in females, 60% for polydactyly in both sexes, and 15% for cardiovascular defects. Given these probabilities, one would expect 9% of males and 3% of females to have the gene in the completely nonpenetrant state. In the Amish, the transverse vaginal septa gene has been localized to chromosome 20p12.