NOT PARA-, NOT PERI-, BUT CENTRIC INVERSION OF CHROMOSOME-12

A 39 year old male with primary infertility was diagnosed as having Kl inefelter syndrome by conventional cytogenetic analysis, which also sh owed an abnormal chromosome 12. Fluorescence in situ hybridisation (FI SH) analysis of the aberrant chromosome using a 12 specific centromeri c probe showed a break in the alphoid repeats followed by an inversion within the short arm, resulting in a pseudodicentric chromosome. Furt her FISH analyses using telomeric and subtelomeric probes showed that the other breakpoint was in the subtelomeric region of the short arm. The karyotype is designated 47,XXY,inv(12) (p10p13.3). To our knowledg e this is the first report of a case of ''centric inversion''.