Defective sexual development in an infant with 46, XY, der(9)t(8;9)(q23.1;p23)mat

We report on a male infant with ambiguous genitalia (scrotal hypospadias, s inus urogenitalis) trisomic for 8q23-ter and monosomic for 9p23-ter, who sh ared craniofacial and other abnormalities with either phenotype. Gonadal hi stology was nearly normal for age. Normal endocrinological findings and exc lusion of mutations in SRY, androgen receptor and alpha-reductase genes poi nt to supplementary gene(s) located in 9p2305-ter, haplo-insufficiency (by deletion) of which is expected to cause defective male morphogenesis. Conclusion This observation lends further support to the hypothesis that ge netic factors are located at 9p23-ter which are involved in normal sex dete rmination.