A novel mutation (c.T3816 > C) in the androgen receptor gene in a 46,XY female patient with androgen insensitivity syndrome.

INTRODUCTION: Androgen receptor (AR) gene mutations are the most frequent cause of 46,XY disorders of sex development (DSD), and are associated with a variety of phenotypes ranging from phenotypic women (Complete Androgen Insensitivity Syndrome or CAIS) to milder degrees of undervirilisation (Partial Androgen Insensitivity Syndrome or PAIS) or men with infertility only (Mild Androgen Insensitivity Syndrome or MAIS). In this paper, we present the results of clinical, endocrine and molecular trials in a patient hospitalised because of primary amenorrhoea with typical phenotype of CAIS. MATERIAL AND METHODS: The main objective of this study was to determine the molecular cause of androgen insensitivity syndrome in a 46,XY female patient. Molecular analysis of the AR gene was conducted using MSSCP (Multitemperature Single Strand Conformation Polymorphism) and sequencing methods. RESULTS: MSSCP analysis showed changes in electrophoretic mobility in exon 8 of the AR gene. Sequencing analysis revealed a missense mutation which has not been previously described. This is a c.T3816 > C transition mutation which causes a S901P substitution in the amino acid chain (based on the latest NCBI reference sequence NM 000044.2). CONCLUSIONS: The identified c.T3816 > C mutation in AR gene provides further evidence for the correlation between specific AR mutations and phenotype corresponding to androgen insensitivity.

A novel mutation (c. 341A>G) in the SRY gene in a 46,XY female patient with gonadal dysgenesis.

SRY (sex-determining region Y) gene, MIM 480000, NM_005634) is crucial for sex differentiation which encodes the protein responsible for initiating testis differentiation. SRY mutations are associated with the presence of XY gonadal dysgenesis symptoms. We studied a 46,XY female patient with primary amenorrhoea and negative family history. The clinical, endocrine, histopathologic and cytogenetic data are consistent with gonadal dysgenesis. Using a molecular analysis, a novel (c.341A>G, p. N65D) missense mutation within the HMGbox of SRY gene was detected. Escherichia coli expression of SRY study showed reduced expression of the mutated protein and gel retardation assay method revealed lowered DNA-binding ability in N65D variant of SRY. The novel mutation detected in the SRY gene may be an aetiopathogenic factor in clinically defined 46,XY complete gonadal dysgenesis (CGD). Because of an increased risk of gonadoblastoma, proper early diagnosis and treatment prevent development of malignancies.