5-alpha-reductase deficiency


5-alpha reductase deficiency is a rare condition. Patients with 5-alpha-reductase deficiency do not produce enough dihydrotestosterone (DHT), a hormone which has a critical role in male sexual development, and a shortage of this hormone disrupts the formation of the external sex organs before birth. Many patients have been found in several countries such as Dominican Republic, Papua New Guinea, Turkey, and Egypt. The cause of 5-alpha-reductase deficiency is not clear. Researchs demonatrate that mutations in the SRD5A2 gene may play a role in the cause of the disease. Some patients with 5-alpha reductase deficiency may show female external genitalia in infancy. When the child grows up, she/he may show ambiguous genitalia, or a girl appears virilisation, or a boy does not appear virilisation. Usual complications are osteoporosis and psychosexual dysfunction. Diagnosis measure includes testosterone-to-dihydrotestosterone (T/DHT) level detecting, mutation analysis of the 5-alpha-reductase type 2 gene, tests of urinary ratios of various metabolites and images of cavitas pelvis. Treatments include hormone replacement therapy, vaginoplasty, feminizing genitoplasty and psychosocial support.

Biochemical effects of 5-alpha-reductase deficiency-2 in testosterone biosynthesis. Typically levels of testosterone are elevated, while levels of DHT are significantly decreased, leading to male undervirilization.

How do I know if I have 5-alpha-reductase deficiency and what are the symptoms?

  • Infancy: Some patients with 5-alpha reductase deficiency may show female external genitalia. Some may appear male external genitalia. Others show with ambiguous genitalia.
  • Puberty: Patients raised as girls often appear virilisation, such as amenorrhoea, hirsuitism, deepening of the voice, descending of the testes, enlarged clitoris or microphallus, and the urethra attaching to the phallus.
  • Adulthood: In adulthood, lack of dihydrotestosterone (DHT), patients with 5-alpha-reductase deficiency may not appear virilisation and experience male-pattern baldness.

Who is at risk for 5-alpha-reductase deficiency?

Researchs demonatrate that mutations in the SRD5A2 gene cause 5-alpha reductase deficiency. As a result of SRD5A2 mutations, the body cannot effectively convert testosterone to dihydrotestosterone (DHT), which plays an important role in the formation of external genitalia before birth.

How to know you have 5-alpha-reductase deficiency?

  • Testosterone-to-dihydrotestosterone (T/DHT) level: In patients with 5-alpha-reductase deficiency, the testosterone level is normal or modestly elevated, whereas the DHT level is much low. Then, testosterone-to-dihydrotestosterone (T/DHT) level may be increased.
  • Mutation analysis of the 5-alpha-reductase type 2 gene: It is primarily a research tool and not commercially available at present.
  • Urinary ratios of various metabolites: These are also not commercially available currently.
  • Pelvis ultrasonography: This is an painless test which uses sound waves to create a picture of the internal organs. For patients with 5-alpha-reductase deficiency, pelvis ultrasonography may be for differential diagnosis.
  • Vaginogram: In patients with 5-alpha-reductase deficiency, vaginogram may be used to measure vaginal length and show no fistulous connections between the urinary tract and vagina.

When to seek urgent medical care?

Call your health care provider as soon as possible if your kid has symptoms of 5-alpha-reductase deficiency, such as a kid shows ambiguous genitalia, or a girl often appears virilisation, or a boy does not appear virilisation.

Treatment options

Patients with 5-alpha-reductase deficiency have many treatment options. The options are hormone replacement therapy, surgery and psychosocial support. Talk to your kid’s doctor about treatment options and your family’s preferences on treatment decisions.

  • Gender assignment: The major issue for patients with 5-alpha-reductase deficiency is gender assignment. Most of these children are assigned a female gender at birth, while some kids adopt male gender identity and a male gender role at puberty.
  • Hormone replacement therapy: Some evidence suggests that dihydrotestosterone (DHT) therapy administered prior to puberty may increase penile size for male gender identity. For female gender identity, either ethinyl estradiol or conjugated estrogens can be used for hormone replacement therapy after gonadectomy which my ba performed prior to puberty.
  • Surgery: Vaginoplasty and feminizing genitoplasty are two main surgery for patients with 5-alpha-reductase deficiency. Vaginoplasty is required for most patients who remain female. Many surgeons recommend to perform the surgery until the kid is an adolescent or young adult. Feminizing genitoplasty has usually been performed on infants with 5-alpha-reductase deficiency in the United States and many other industrialized countries. The surgery includes: cutting off the testes, restructuring the labioscrotal folds into clear labia, and providing a more clitoral appearance.
  • Psychosocial support: Appropriate psychosocial support for the child and family is important. They can supply accurate and complete information about the disease, provide emotional support of the family, facilitate communication between the family and medical team, and help provide age-appropriate information to the child when he grows up.

Diseases with similar symptoms

  • Congenital adrenal hyperplasia
  • Androgen insensitivity syndrome
  • Testis degeneration
  • True hermaphroditism
  • 45,X/46,XY gonadal dysgenesis

Where to find medical care for 5-alpha-reductase deficiency?

Ask our experts on 5-alpha-reductase deficiency

Prevention of 5-alpha-reductase deficiency

THe cause of 5-alpha-reductase deficiency is gene mutation. Preventive meaures are unknown. For people with family history, gene screening test may be needed.

What to expect (Outlook/Prognosis)?

Most affected males are unable to father a child. Osteoporosis and psychosexual dysfunction are usual complicatrions of patients with 5-alpha-reductase deficiency.




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