XYY Genotype

Abstract

THE phenotypic manifestations resulting from sex-chromosome abnormalities in man have been fairly well defined for a number of conditions involving abnormal X-chromosome dosage (XXY, XXX, XXXX, XO and so forth), but not for the XYY male, owing to the apparent rarity of this condition. Previous communications1 , 2 have described the cytogenetic and clinical aspects of an adult male with the XYY chromosome constitution, the first patient with this abnormal karyotypic picture. The present paper describes some of the clinical and cytogenetic facets of another subject with the XYY syndrome.Clinical DataThe patient, a twelve-year-old boy, was found to have undescended . . .