TESTICULAR DEVELOPMENT IN AN SRY-NEGATIVE 46,XX INDIVIDUAL HARBORING A DISTAL XP DELETION

A case of a true hermaphrodite presenting with a karyotype of 46,X,del (X)(p21.1-->pter) is described. The testis-determining gene, SRY, was not detected in DNA prepared from either peripheral blood lymphocytes or from a gonad biopsy. The patient also presented with a series of di screte somatic abnormalities, including abnormal skin and retinal pigm entation, and mental retardation. The extent of the Xp deletion was ma pped by Southern blotting. X chromosome replication studies of lymphob last cells prepared from the patient indicated that the deleted X chro mosome was inactivated in all cells examined. It is suggested that the phenotype of the patient is caused by the unmasking of a recessive al lele(s) on the grossly intact X chromosome. The relationship between t he Xp deletion, the intersex phenotype, and the possible role of an Xp locus involved in human sex determination is discussed.