A case report of 46,XY partial gonadal dysgenesis caused by a novel mutation in the sex-determining region gene.

The sex-determining region Y (SRY) gene is a key gene involved in male sex differentiation and development. Patients with 46,XY disorders of sex development related to mutations in the high mobility group (HMG) box typically present with complete gonadal dysgenesis. In this study, we report a case of novel missense mutation c.T281G within the HMG domain of SRY in a 15-year-old patient of the female gender with 46,XY partial gonadal dysgenesis (PGD). The novel missense mutation caused the substitution of codon 94 for leucine in the HMG box of the SRY protein with an arginine codon. Leucine and arginine are aliphatic amino acids, and three-dimensional protein structure prediction revealed only slight structural changes in the SRY protein. Thus, the SRY protein had maintained some of its functions, and the patient presented with PGD. In conclusion, we identified a novel SRY mutation in a patient with 46,XY PGD. Based on the protein model, we believe that the mutation in the HMG domain helped to maintain the partial function of the SRY protein. The condition of our patient differed from the well-known 46,XY complete gonadal dysgenesis caused by mutations in the HMG region. In fact, this is the first case of 46,XY PGD caused by mutations in the HMG region to be reported, and therefore, our experience has expanded the mutation spectrum of the SRY gene. Furthermore, the present case demonstrates that mutations located in the HMG domain of SRY gene cannot be ruled out in patients with a clinical diagnosis of 46,XY PGD.