Case Report: a Novel Nonsense Mutation in the Androgen Receptor Gene Causing the Complete Androgen Insensitivity Syndrome

Androgen insensitivity syndrome (AIS) is a rare X-linked genetic disorder caused by mutations in the androgen receptor (AR) gene. AIS can be divided into partial type (PAIS), mild type (MAIS), and complete type (CAIS) based on the degree of androgen insensitivity. CAIS is characterized by a male genotype and a complete female phenotype. A 10-year-old child presented with a bilateral inguinal mass for 9 years. Physical examination revealed a complete feminine genital appearance and a painless mass in bilateral inguinal area. Pelvic magnetic resonance imaging (MRI) revealed long T1 and T2 elliptic signal nodules in bilateral inguinal area, absence of uterus-ovary signal and a short blind end of the vagina. Chromosomal analyzes manifested a 46, XY karyotype. By analyzing the above clinical data, the preliminary diagnosis of CAIS was confirmed. Then laparoscopic bilateral gonadectomy was performed. The histological examination of resected gonad showed it consisted of dysplastic testicular tissue and no signs of malignancy were observed. Sanger sequencing revealed the presence of a hemizygous mutation c.927 T > G (p. Tyr309*) in exon 1 of the AR gene. This is the first report of a novel nonsense mutation.