Klinefelter's syndrome
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Introduction
47, XXY karyotype
Epidemiology
- occurs in 1/400-700 men
Pathology
- failure of the seminiferous tubules
- azoospermia
- diminished testosterone production following onset of seminiferous tubular failure
- excessive production of estradiol by Leydig cells
- estradiol increases serum testosterone estrone-binding globulin elevated total serum testosterone
Genetics
47, XXY karyotype
Clinical manifestations
- tall stature
- gynecomastia
- testicular failure
- hypogonadism
- sexual dysfunction
- decreased sexual hair
- decreased muscle mass[1]
- fatigue[1]
Laboratory
- elevated serum FSH
- serum LH may be elevated
- serum testostenone may be low or normal
- serum free testosterone is generally low
- semen analysis for azoospermia
- karyotyping
Management
- fertility may be achieved with ejaculated sperm
- some couples opt for preimplantation genetic testing & embryo biopsy to avoid transmitting the disorder to offspring
- after fertility issues resolved exogenous androgens may be considered to prevent osteoporosis
- oral testosterone undecanoate (Jatenzo) FDA-approved[3]
More general terms
Additional terms
References
- ↑ 1.0 1.1 1.2 Medical Knowledge Self Assessment Program (MKSAP) 11, 17, 19. American College of Physicians, Philadelphia 1998, 2015, 2022
- ↑ Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 380
- ↑ 3.0 3.1 FDA News Release. March 27, 2019 FDA approves new oral testosterone capsule for treatment of men with certain forms of hypogonadism. https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm634585.htm