Identification of a new nonsense mutation (Tyr129Stop) of the SRY gene in a newborn infant with XY sex-reversal.

Point mutations and deletions of SRY gene have been described in several cases of XY gonadal dysgenesis. To date, most of these mutations affect the HMG domain of SRY which plays a central role in DNA binding activity of SRY. We report on a non-mosaic XY sex-reversed newborn girl (completely female external genitalia). The direct sequencing of SRY showed a new nonsense mutation in a codon of SRY gene flanking the 3' end of the HMG domain: a thymine is replaced by a guanine at position +387 in codon 129, resulting in the replacement of the amino acid tyrosine (TAT) by a stop codon (TAG). The new mutation of this patient provides further evidence to support the functional importance of the putative DNA binding activity of the HMG-box domain.