Turner syndrome: Characteristics and complications

Turner syndrome: Characteristics and complications

Turner syndrome is a disorder that occurs when there is a complete or partial monosomy of the X chromosome. Turner syndrome is associated with one of the following 3 types of karyotypic abnormalities·       

45,X karyotype ( in which no Barr bodies are seen in the buccal smear)·        mosaics (45, X cell plus one or more karyotypically normal or abnormal cell types)·       

Structural abnormalities of the X chromosomes which result in partial monosomy of the X chromosome. E.g. deletion of one of the arms of the X chromosome.

This karyotypic heterogeneity associated with Turner’s syndrome is responsible for significant variations in phenotype. E.g. 45, XO causes a severe phenotype whereas mosaics may have a normal appearance with only primary amenorrhea.

Turner syndrome is characterized by female hypogonadism and its secondary effects.      

Replacement of the ovaries by fibrous streaks.      

Decreased estrogen production & increased pituitary gonadotropins from loss offeedback inhibition.
Infantile genitalia and poor breast development and little pubic hair.      

Short stature (rarely exceeding 150cm in height), webbed neck, shield-like chestwith widely spaced nipples, and wide carrying angles of the arms.

Lymphedema of the extremities and neck.

Congenital heart disease (especially preductalcoarctation of the aorta and bicuspidaortic valve).

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