MATERNAL UNIPARENTAL DISOMY FOR CHROMOSOME-22 IN A CHILD WITH GENERALIZED MOSAICISM FOR TRISOMY-22

We report on a case of generalized mosaicism for trisomy 22. At chorio nic villus sampling (CVS) in the 37th week of pregnancy, a 47,XX, + 22 karyotype was detected in all cells. The indication for CVS was sever e unexplained symmetrical intrauterine growth retardation (IUGR) and a ventricular septal defect (VSD) was noted. In cultured cells from amn iotic fluid taken simultaneously, only two out of ten clones were tris omic. At term, a growth-retarded girl with mild dysmorphic features wa s born. Lymphocytes showed a normal 46,XX[50] karyotype; both chromoso mes 22 were maternal in origin (maternal uniparental disomy). Investig ation of the placenta post-delivery using fluorescence in situ hybridi zation showed a low presence of trisomy 22 cells in only one out of 14 biopsies. In cultured fibroblasts of skin tissue, a mosaic 47,XX, + 2 2[7]/46,XX[25] was observed. Clinical follow-up is given up to 19 mont hs.