5α Reductase Deficiency—a Rare Cause of Ambiguous Genitalia and Gender Dysphoria

We present a case of pseudovaginal perineoscrotal hypospadias, secondary to 5α-reductase deficiency presenting as gender dysphoria. This particular enzyme deficiency accounts for only a small number of disorders of sexual development cases worldwide. A feature of this disorder is the presence of ambiguous genitalia at birth followed by the development of male secondary sexual characteristics during puberty when testicular production of testosterone can compensate for previous low circulating levels of 5-dihydrotestosterone (DHT). Our described patient, raised female, presented with gender dysphoria with no male secondary sexual features given a bilateral orchidectomy in infancy. Initial testing showed biochemical primary hypogonadism and whole-genomic sequencing demonstrated pathogenic compound heterozygous variants in the <i>SRD5A2</i> gene. Treatment was commenced with injectable testosterone undecanoate leading to development of desired male secondary sexual characteristics.