We tested a female patient with 46,XY karyotype and pure gonadal dysgenesis for the presence of the SRY gene and for mutations within the SRY conserved domain. A point mutation was identified at nucleotide position 209 with respect to the first ATG. The base substitution is a G-->A transition in the first nucleotide of codon 70 which changes a tryptophan (TGG) to a stop codon (TAG). Even though the father was not available for investigation we assumed that it is a de novo mutation, since it probably generates a nonfunctional truncated protein.