A novel mutation 5' to the HMG box of the SRY gene in a case of Swyer syndrome

We describe a novel mutation in the coding region of the SRY gene in a 46,XY female with Swyer syndrome. Analysis of SRY was carried out by direct sequencing of a 780-bp PCR product that included the SRY open reading frame (ORF). This revealed the presence of a point mutation, ins108A, in the coding region 50 to the HMG box which results in a frame shift and premature termination of the encoded protein. No other mutation was found in the SRY ORF. We infer that sex reversal in this individual is a result of this insertion. In none of the 13 other 46,XY females that were studied was a mutation detected in SRY, confirming earlier findings that most cases of XY femaleness are due to causes other than mutation in SRY. These observations and those of others are discussed in relation to the aetiology of XY sex reversal