DNA testing of Klinefelter's syndrome in a criminal case using XY chromosomal STR multiplex-PCR

We report genetic typing of Klinefelter's syndrome applied to casework in forensic DNA testing. In this case, by using extracted DNA from body samples (muscle and bones), we could identify two distinct X alleles in two out of three X-STR loci (HPRTB and ARA), in addition to Y alleles (DYS390, DYS393). The extra X was found to have originated from father, and the victim turned out to have 47XXY Klinefelter's syndrome. The victim was a 30-year-old male, born from relatively elderly parents as a second child. His father was a severe alcoholic and had been malnourished for more than 20 years at the moment of his birth. He exhibited slight mental retardation as a child, and belonged to a criminal group as an adult. The method presented here was useful to accurately diagnose sex chromosomal abnormality instead of conventional chromosomal analysis and Xg blood group typing. A subtype of this syndrome, 48 XXXY or mosaic, for example, could be identified if the intensity of the overlapped X bands were calculated.