5-alpha reductase deficiency Flashcards
What is 5-alpha reductase deficiency?
5α-Reductase 2 deficiency is an autosomal recessive condition caused by a mutation in SRD5A2
The condition is rare, only affects males and has a broad spectrum of presentations most apparent in the genitalia.
What is the function of 5-alpha reductase?
5αR2 is expressed in specific tissues and catalyzes the transformation of testosterone (T) to 5α-dihydrotestosterone (DHT), which plays a key role in the process of differentiation in the external genitalia and the prostate during sexual development in the male fetus
What does 5-alpha reductase deficiency lead to in sexual development?
5αR2D is a result of impaired 5αR2 activity leading to a spectrum of phenotypes including overt genital ambiguity, female appearing genitalia, hypospadias, penile urethra, and isolated micropenis
What is the karyotype for 5-alpha reductase deficiency?
46,XY DSD
What are the internal reproductive organs for 5-alpha reductase deficiency?
Male: vasa deferentia, seminal vesicles, epididymides and ejaculatory ducts
What happens during puberty for individuals with 5-alpha reductase deficiency?
Virilization of genitalia with voice deepening, development of muscle mass occur at puberty in affected males and height is not impaired
Gynecomastia is uncommon
Hair on face and body is reduced, and male pattern baldness does not occur
How do people with 5-alpha reductase deficiency often present?
Feminised external genitalia, small phallus, hypospadias
Pseudovaginal perineoscrotal hypospadias presenting with female appearing genitalia and pubertal virilization is the classical syndrome attributed to 5αR2D
What are the diagnostic features of female presenting 5-alpha reductase deficiency?
Enlarged clitoris, posterior labial fusion, and inguinal/labial mass
What are the diagnostic features of male presenting 5-alpha reductase deficiency?
For apparent male genitalia: nonpalpable testes, micropenis, isolated perineal hypospadias, or mild hypospadias with undescended testis
How would you manage someone with 5-alpha reductase deficiency?
Historically most 5αR2D individuals have been “raised as females”, but later reports show that over half of patients who underwent virilizing puberty adopted a male gender identity thus challenging historical practices
Life-long hormonal treatments as also required for the development and maintenance of female secondary sex characteristics. Male sex of rearing avoids lifelong hormonal treatments and allow for the potential of fertility
What is the effect of 5-alpha reductase deficiency on fertility?
Spontaneous fertility in 5αR2D affected males is usually not possible (though has been observed) due to semen abnormalities that include reduced sperm counts, high semen viscosity and, in some cases, lack of primary spermatocytes
