MATERIALS AND METHODS: Seventy two probands that were referred to division of Human Genetics, St.John's Medical College, Bangalore with variable complaints and phenotypic features were diagnosed with informed consent as Klinefelter syndrome with a confirmed karyotype. The Karyotype was prepared by peripheral lymphocyte culture and GTG banding method. The parental origin was studied in 9 families of Klinefelter probands with standard protocol for GENE SCAN using X-chromosome specific Short Tandem Repeat markers. The outcome was analyzed to determine the parental origin by GENE MAPPER.

STATISTICAL ANALYSIS: STATISTICAL ANALYSIS was conducted to ascertain the significance of parental origin of supernumerary X with the phenotypic profile with confirmed karyotype.

RESULTS: Seven of nine probands had 47, XXY karyotype and 2 were mosaic with 47,XXY/46,XY karyotype. Five probands had their supernumerary X from maternal side and four were paternally derived. Sixteen features as framed proforma were tabulated against the originated X in Klinefelter probands. 55.56% of Klinefelter stigmata were seen in prob and who had maternally derived X and the rest were with paternal X.