Wednesday, June 25, 2008

- Klinefelter's syndrome.

Klinefelter's syndrome

*Def:- It is a condition in which males have an extra X sex chromosome (i.e XXY) in his cells(1).

  • The most common sex chromosome disorder (2).
  • The second most common condition caused by the presence of extra chromosomes.
  • Roughly it occur by 0.1% in males.
* Klinefelter syndrome is named after Dr. Henry Klinefelter, an endocrinologist at Massachusetts General Hospital in Boston, Massachusetts, who first described it in 1942 (3).

  • Most commonly Due to non-disjunction of chromosome X at one of the meiotic divisions so an ovum with XX chromosome when fertilized by a sperm carrying Y chromosome lead to formation of baby with XXY .
  • less commonly,the condition arise when a normal ovum is fertilized by XY sperm .
  • The condition may appear with XXXY or XXXXY due to non-disjunction at both meiotic divisions this will lead to more mental retardation.
*Karyotype (1) :-
  • 47,XXY
  • 48,XXXY
  • 49,XXXXY
*Buccal smear:- +ve Barr's body.

*Hormonal assay:- decrease androgens.

*Clinical picture:-

  • Infertility.
  • Gynecomastia.
  • Subnormal intelligence or Mental retardation.
  • microorchidism (i.e. small testicles)(4).
  • Absence of body hair.
  • Long stature (due to absence of androgens which help closure of epiphysis).

Return to list of medical syndromes here

(1) Principles of histology vol1,staff members ,faculty of medicine,mansoura university,ch3,p.g75.
(2)James, William; Berger, Timothy; Elston, Dirk (2005). Andrews' Diseases of the Skin: Clinical Dermatology. (10th ed.). Saunders. p 549. ISBN 0721629210.
(3)Klinefelter, HF Jr; Reifenstein, EC Jr & Albright (1942), "Syndrome characterized by gynecomastia, aspermatogenesis without a-Leydigism and increased excretion of follicle-stimulating hormone", J Clin Endocrinol Metab 2: 615–624. Klinefelter, HF (1986), "Klinefelter's syndrome: historical background and development", South Med J 79(45): 1089–1093 talks about the history of the development of the literature.
(4)Leask, Kathryn (October 2005). "Klinefelter syndrome" (HTML). National Library for Health, Specialist Libraries, Clinical Genetics. NationalLibrary for Health. . Retrieved 2007-04-07.

No comments:

Post a Comment

Nice to see your comment here........