Somatic mosaicism of androgen receptor gene in an androgen insensitivity syndrome patient conceived through assisted reproduction technique

Background: Mutations of human androgen receptor (AR) gene are responsible for androgen insensitivity syndrome (AIS). Variable phenotypes and androgen receptor binding activity have permitted the classification of AIS into complete (CAIS), partial (PAIS), and minimal or mild (MAIS) forms. Somatic mosaicism in AIS is a rare condition which happened when de novo mutations occur after the zygotic stage.

Methods: Clinical evaluation, hormone measurements, and molecular analysis were performed to diagnose the patient in the study.

Results: A 46, XY girl who conceived through in vitro fertilization (IVF), presented with partial virilization of external genitalia, was found to have the p.C620R in heterozygosity. The variant p.C620R of AR has been previously reported in a patient with completely feminized external genitalia, which was inherited from the heterozygote carrier mother. Mutation analysis of the mother of our patient revealed that the variant was de novo and presented as a somatic mosaicism which indicated an insufficient amount of wild-type AR in our patient.

Conclusion: This is the first case that AIS was caused by de novo mutation of AR in a 46, XY Disorder of Sexual Development (DSD) patient by the assisted reproduction technique (ART). The phenotype of partial virilization could be explained by AR mutation in somatic mosaicism.