RESUMO
OBJECTIVES: Steroid 5α-reductase type 2 deficiency (5α-RD2) is an autosomal recessive disorder caused by mutations in the SRD5A2 gene. This condition is characterized by reduced enzymatic activity of the 5α-reductase type 2 enzyme. Individuals with mutations in the SRD5A2 gene may exhibit various symptoms of under-masculinization in 46, XY individuals. We conducted a comprehensive analysis of the SRD5A2 gene in a patient with disorder of sex development (DSD). CASE PRESENTATION: We describe a patient with a homozygous Gly183Ser variant in the SRD5A2 gene. Their sibling also carries this variant in homozygosity, while both parents have it in a heterozygous state. The patient presents with predominantly female traits and was raised as a girl. Although the siblings exhibit distinct phenotypic characteristics, both have assumed a male gender identity. CONCLUSIONS: This study reveals different phenotypes for the two siblings, highlighting the complexity of establishing a genotype-phenotype correlation in the SRD5A2 gene. It is noteworthy that the Gly183Ser variant seems to be more prevalent among individuals of African descent, aligning with our patient's ethnic background.