Trisomy 18/trisomy 13 mosaicism in an adult with profound mental retardation and multiple malformations

Abstract

We report on an adult woman with profound mental retardation and multiple anomalies who consists of 3 cell lines: one with trisomy 18, one with trisomy 13, and a normal cell line. Her phenotype includes manifestations of both trisomy syndromes. The origin of these cell lines could have been a doubly aneuploid (48,XX + 13, + 18) or singly aneuploid (47,XX + 18 or 47,XX + 13) zygote with subsequent mitotic nondisjunctions, or a normal zygote with multiple mitotic nondisjunctions. There have been four previous reports of mosaicism involving both trisomy D and trisomy E; all died in the first six months of life. Two of these cases had a doubly aneuploid (48,XX, + D + E) cell line. Our patient illustrates the need for study of several tissues in patients with complex aneuploidy syndromes or atypical manifestations of a given syndrome (such as prolonged survival), as well as the need for caution in counseling families about prognosis for survival in autosomal trisomies which usually are lethal.

Hypomelanosis of Ito with trisomy 18 mosaicism

“…To date, including our patient, mosaicism for trisomy 18 in association with the specific pigmentary dysplasia phenotype called HI has been reported 9 times [Atnip and Summit, 1971;Chemke et al, 1983;Wilson et al, 1983;Golden and Kaplan, 1986;Sybert et al, 1990;Chitayat et al, 1990;Murano et al, 19911. A wide variety of chromosome abnormalities, overwhelmingly in the mosaic form, were found in pigmentary dysplasia so that skin dyspigmentation has been postulated as a marker for nonspecific chromosome mosaicism [Flannery, 19901.…”