Detection of Molecular Variations at Androgen Receptor Gene in 46,XY Differences in Sex Development Cases

One of the common causes of 46,XY differences in sex development (DSD) cases is androgen insensitivity syndrome. This X-linked recessive inherited condition is associated with pathological variations of the AR gene, leading to defects in androgen action. Affected 46,XY infants or individuals experience variable degrees of undervirilization and those with severe form will have female-like external genitalia. Therefore, they were more likely assigned and reared as females. The confirmatory molecular test is often needed due to similar clinical manifestations with other conditions causing 46,XY DSD. Since in our country, the molecular test for the AR gene is lacking, the study is conducted as a preliminary study to elaborate on the possibility of developing a molecular test for the AR gene in 46,XY DSD cases.

Archived DNAs of 13 46,XY DSD cases were analyzed using polymerase chain reaction and direct sequencing for molecular defects in the AR gene. Clinical and hormonal data were collected and analyzed.

The study successfully amplified and visualized the eight exons of the AR gene and revealed two subjects carrying AR gene variants at exon 7. In the first case, 1.2-year-old boy carried heterozygous p.Gln825Arg, which has never been reported elsewhere, and the second subject, a 2.1-year-old girl with heterozygous p.Arg841His. Both subjects presented with severe undervirilization of external genitalia with external genitalia masculinization scores (EMS) of 1.5 and 3.

In this series, two of 13 46,XY DSD cases carried variants at the AR gene, resulting in complete androgen insensitivity syndrome.