5-alpha-reductase deficiency
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5-alpha-reductase deficiency
Pathology
Male and female reproductive system disorders
Precocious puberty
Delayed puberty
Klinefelter syndrome
Turner syndrome
Androgen insensitivity syndrome
5-alpha-reductase deficiency
Kallmann syndrome
Male reproductive system disorders
Hypospadias and epispadias
Bladder exstrophy
Priapism
Penile cancer
Prostatitis
Benign prostatic hyperplasia
Prostate cancer
Cryptorchidism
Inguinal hernia
Varicocele
Epididymitis
Orchitis
Testicular torsion
Testicular cancer
Erectile dysfunction
Male hypoactive sexual desire disorder
Female reproductive system disorders
Amenorrhea
Ovarian cyst
Premature ovarian failure
Polycystic ovary syndrome
Ovarian torsion
Krukenberg tumor
Sex cord-gonadal stromal tumor
Surface epithelial-stromal tumor
Germ cell ovarian tumor
Uterine fibroid
Endometriosis
Endometritis
Endometrial hyperplasia
Endometrial cancer
Choriocarcinoma
Cervical cancer
Pelvic inflammatory disease
Urethritis
Female sexual interest and arousal disorder
Orgasmic dysfunction
Genito-pelvic pain and penetration disorder
Mastitis
Fibrocystic breast changes
Intraductal papilloma
Phyllodes tumor
Paget disease of the breast
Breast cancer
Hyperemesis gravidarum
Gestational hypertension
Preeclampsia & eclampsia
Gestational diabetes
Cervical incompetence
Placenta previa
Placenta accreta
Placental abruption
Oligohydramnios
Polyhydramnios
Potter sequence
Intrauterine growth restriction
Preterm labor
Postpartum hemorrhage
Chorioamnionitis
Congenital toxoplasmosis
Congenital cytomegalovirus (NORD)
Congenital syphilis
Neonatal conjunctivitis
Neonatal herpes simplex
Congenital rubella syndrome
Neonatal sepsis
Neonatal meningitis
Miscarriage
Gestational trophoblastic disease
Ectopic pregnancy
Fetal hydantoin syndrome
Fetal alcohol syndrome
Reproductive system pathology review
Disorders of sex chromosomes: Pathology review
Prostate disorders and cancer: Pathology review
Testicular tumors: Pathology review
Uterine disorders: Pathology review
Ovarian cysts and tumors: Pathology review
Cervical cancer: Pathology review
Vaginal and vulvar disorders: Pathology review
Benign breast conditions: Pathology review
Breast cancer: Pathology review
Complications during pregnancy: Pathology review
Congenital TORCH infections: Pathology review
Disorders of sexual development and sex hormones: Pathology review
Amenorrhea: Pathology Review
Testicular and scrotal conditions: Pathology review
Sexually transmitted infections: Warts and ulcers: Pathology review
Sexually transmitted infections: Vaginitis and cervicitis: Pathology review
HIV and AIDS: Pathology review
Penile conditions: Pathology review
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5-alpha-reductase deficiency
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Content Reviewers
Rishi Desai, MD, MPHContributors
Antonia Syrnioti, MD
Brittany Norton, MFA
Marisa Pedron
Tanner Marshall, MS
5α- reductase deficiency is a genetic disorder in which a protein called 5α reductase is defective or absent.
That’s an enzyme that converts the male hormone testosterone to its more potent form, called dihydrotestosterone.
One of the most important roles of dihydrotestosterone is to help male external genitalia develop in a male fetus.
Okay, normally, very early on in fetal life, male and female internal sex organs and external genitalia are undifferentiated and look identical.
Within the first few months of development, testes develop in the male fetus.
The testes start producing testosterone - a male steroid hormone that belongs to a class of hormones called androgens.
The testosterone gets released into the blood and a tiny fraction of it gets converted by 5α- reductase, which is mainly made in the skin of the genital area, into dihydrotestosterone.
Over time, dihydrotestosterone levels start rising and it affects undifferentiated genital structures.
Looking closely at these structures, at the top there’s the genital tubercle, which is a small projection.
Just below that, there's the urethral groove, which is the external opening of the urogenital sinus or the future urethra and bladder and is surrounded by the urethral folds and the labioscrotal swellings.
Now, once dihydrotestosterone reaches these structures, it makes the genital tubercle elongate into the phallus which will eventually be the penis.
The elongating genital tubercle pulls up the urethral folds which fuse in the midline, forming the spongy or penile urethra.
The tips of the urethral folds remain unfused and that forms the external urethral opening at the distal tip of the penis.
Sources
- "Robbins Basic Pathology" Elsevier (2017)
- "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
- "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
- "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
- "5-alpha-reductase deficiency: a case report" Paediatrica Indonesiana (2016)
- "Steroid 5agr-Reductase Deficiency in Man: An Inherited Form of Male Pseudohermaphroditism" Science (1974)
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