MOLECULAR AND CYTOGENATE ANALYSIS OF AN X AUTOSOMAL TRANSLOCATION - 45,X,DIC(X-17)(P22.2-P13)/

We present an unusual case of monosomy 17p13-pter and monosomy Xp22.2- pter due to a dicentric translocation chromosome X/17 in a female newb orn with severe anomalies. The karyotype was identified as 45,X,dic(X; 17)(p22.2;p13) by high resolution GTG banding in lymphocytes. R bandin g showed the translocational X-chromosome to be late replicating, and there was no spreading of X-inactivation onto the autosomal segment. F urthermore, it could be demonstrated by C banding that the X-centromer e in the translocation chromosome was inactive. The results of short t andem repeat (STR) typing confirmed the partial monosomy X and 17 as w ell as the paternal origin of the two chromosomes X and 17 which were involved in the translocation chromosome formation. The cell stage of the structural rearrangement was consistent with paternal meiosis as w ell as with postzygotic mitosis. The monosomy was confirmed in lymphoc ytes and fibroblasts, and mosaicism was not detected.