|Embryology - 23 May 2019 Expand to Translate|
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LD50.3 Klinefelter syndrome
|ICD-11 LD50.3 Klinefelter syndrome|
Klinefelter syndrome (47,XXY, XXY syndrome or condition, XXY trisomy) affects male physical and cognitive development. The extra copy of genes on the X chromosome interferes with male sexual development and can prevent the normal function of the testis testes, reducing the levels of testosterone. The signs and symptoms vary among affected individuals.
Rare variations include 47,XXY/46,XY (mosaic syndrome) and Poly-X Klinefelter syndrome: 48,XXYY (or tetrasomy), 48,XXXY (or tetrasomy) and 49,XXXXY (or pentasomy).
First described in 1942 by Dr Harry Klinefelter.
Some Recent Findings
|More recent papers|
This table allows an automated computer search of the external PubMed database using the listed "Search term" text link.
Affects male physical and cognitive development. Small testes that do not produce as much testosterone as usual.
- delayed or incomplete puberty, breast enlargement (gynecomastia), reduced facial and body hair, and an inability to have biological children (infertility).
- Some affected individuals also have genital differences - undescended testes (cryptorchidism), (hypospadias), or an unusually small penis (micropenis).
- Children may have learning disabilities and delayed speech and language development. Tend to be quiet, sensitive, and unassertive, but personality characteristics vary among affected individuals.
- Older children and adults tend to be taller than their peers.
(Text modified from Genetics Home Reference - Klinefelter syndrome)
Molecular Genetics Tests
- Detection of homozygosity
- Deletion/duplication analysis
- Targeted variant analysis
- Sequence analysis of the entire coding region
48,XXYY and 48,XXXY
Much less frequent variants
- 48,XXYY - 1 per 17,000 male births.
- often tall, may have an eunuchoid habitus with long legs, sparse body hair, small testicles and penis, hypergonadotropic hypogonadism, and gynecomastia. IQ level is in the range of 60–80, with delayed speech.
- 48,XXXY - 1 per 50,000 male births.
- prone to hyperactivity, aggression, conduct, and depression compared to males with 47,XXY.
- Klinefelter HF. Reifenstein EC. and Albright F. Syndrome characterized by gynecomastia aspermatogenes without A-Leydigism and increased excretion of follicle stimulating hormone. (1942) J Clin Endocrinol Metab. 2:615–627.
Giudice MG, Del Vento F & Wyns C. (2019). Male fertility preservation in DSD, XXY, pre-gonadotoxic treatments - Update, methods, ethical issues, current outcomes, future directions. Best Pract. Res. Clin. Endocrinol. Metab. , , . PMID: 30718080 DOI.
Los E & Ford GA. (2019). Klinefelter Syndrome. , , . PMID: 29493939
Gravholt CH, Chang S, Wallentin M, Fedder J, Moore P & Skakkebæk A. (2018). Klinefelter Syndrome: Integrating Genetics, Neuropsychology, and Endocrinology. Endocr. Rev. , 39, 389-423. PMID: 29438472 DOI.
Juel Mortensen L, Lorenzen M, Jørgensen N, Andersson AM, Nielsen JE, Petersen LI, Lanske B, Juul A, Hansen JB & Blomberg Jensen M. (2019). Possible link between FSH and RANKL release from adipocytes in men with impaired gonadal function including Klinefelter syndrome. Bone , 123, 103-114. PMID: 30914274 DOI.
GRIGNON CE & GRIGNON J. (1947). [Not Available]. Union Med Can , 76, 1254. PMID: 18899536
SUSMAN E. (1947). Reifenstein-Klinefelter-Albright syndrome. Med. J. Aust. , 2, 155. PMID: 20344569
BETTINGER HF & ROBINSON B. (1946). The Klinefelter-Reifenstein-Albright syndrome. Med. J. Aust. , 2, 446-9. PMID: 21002506
Search Pubmed: Klinefelter syndrome
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- Genetics Home Reference Klinefelter syndrome
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Cite this page: Hill, M.A. (2019, May 23) Embryology Klinefelter syndrome. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Klinefelter_syndrome
- © Dr Mark Hill 2019, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G