Summary of Turner’s syndrome

 

Turner’s syndrome

Definition:

This syndrome is caused by the lack of sex chromosome (XO instead of XX).

Genetic disorder

It is a numerical genetic disorder also call monosomy

Genotype

Monosomy of sex chromosome (2n-1), here only one X chromosome, is present in females.

Chromosomal complement in somatic cell

45X0

Phenotype

Affected individuals are phenotypically female

Occurrence

1 in 2500 phenotypic females.

Symptome

Lymphedema, underweight and swelling or thickness of the neck.they have  underdeveloped breasts, uterus, vulva or vagina,but ovaries are not developed, so primary amenorrhea occurs, associated dysfunctions are hearing impairment, cardiovascular dysfunctions, shield chest with pin-point nipples, low set ear, bilateral cubital valgus, coarctation of aorta, and other congenital anomalies. 

Stature

Short stature

Gonadal sex

Are absent

Cause

Turner syndrome is not related to advanced maternal age; and in fact, is more likely due to instability of the Y chromosome leading to its loss during male meiosis since 75–80% of X chromosomes in TS patients are maternal in origin.

Cause of genetic disorder

Nondisjunction, anaphase lag

Barr body

Female  but barr body is absent due to absence of one  X chromosome

Treatment

There is no cure for Turner syndrome. It is commonly treated with replacement therapy including estrogen and growth hormones.

Gonad

Ovaries are not developed