Turner Syndrome
*Def :- It is a condition in which a female has only one X sex chromosome instead of XX in her cells (i.e XO or monosomy ) (1).
*Synonyms:-
- Ullrich-Turner syndrome.
- Gonadal dysgenesis (2).
*Pathophysiology:-
- Most commonly due to non-disjunction of chromosome X during formation of ova so ovum with one X chromosome when fertilized an by sperm carrying X chromosome give baby with XO.
- It occurs also in normal ovum when fertilized with sperm neither X nor Y .
* Although in females,only one X chromosome is active , the presence of two X chromosomes is essential for development of the ovaries (1).
*Karyotype (1) :- 45,XO
*Buccal smear:- -ve Barr's body.
*Hormonal assay:- decrease sex hormones.
* Clinical picture (1):-
- Short stature ( most common presentation).
- Lymphedema (swelling) of the hands and feet
- Broad chest (shield chest) and widely-spaced nipples
- Low hairline
- Low-set ears
- infertility ( due to ovarian dysgenesis)
- Amenorrhea, or the absence of a menstrual period
- Increased weight, obesity
- Shield shaped thorax of heart
- Shortened metacarpal IV (of hand)
- Small fingernails
- Characteristic facial features (e.g hypertelorism,epicanthic fold,narrow maxilla)
- Webbed neck from cystic hygroma in infancy.
- Congenital heart diseases in 35% of cases mainly Coarctation of the aorta.
- Poor breast development.
- Congenital renal diseases (e.g Horseshoe kidney).
- Cubitus valgus ( wide carrying angle).
- Mental development is subnormal "but intelligence is normal".
*Prognosis:-
While most of the physical findings in Turner syndrome are harmless, there can be significant medical problems associated with the syndrome.
*Treatment:-
As a chromosomal condition, there is no cure for Turner syndrome. However, much can be done to minimize the symptoms. For example:-(3)
- Growth hormone, either alone or with a low dose of androgen, will increase growth and probably final adult height. Growth hormone is approved by the U.S. Food and Drug Administration for treatment of Turner syndrome .(3)
- Estrogen replacement therapy at 14-15 years has been used since the condition was described in 1938 to promote development of secondary sexual characteristics.Estrogens are crucial for maintaining good bone integrity and tissue health (3).
Return to list of medical syndromes here
*References:-
(1) Principles of histology vol1,staff members ,faculty of medicine,mansoura university,ch3,p.g76.
(2)James, William; Berger, Timothy; Elston, Dirk (2005). Andrews' Diseases of the Skin: Clinical Dermatology. (10th ed.). Saunders. ISBN
0721629210.
(3)Turner Syndrome Society of the United States. "
FAQ 6. What can be done? Retrieved 2007-05-11.
