Turner’s syndrome is characterized by following except:
Question Category:
Correct Answer:
Tall stature
Description:
Ans. D. Tall stature. (Ref. Harrison's 18th/pg. 3049; Chapter 349.)Turner's Syndrome (Gonadal Dxsgenesis: 45.X)# PATHOPHYSIOLOGY- Approximately one-half of individuals with Turner's syndrome have a 45,X karyotype, about 20% have 45,X/46,XX mosaicism, and the remainder have structural abnormalities of the X chromosome such as X fragments, isochromosomes, or rings. The clinical features of TS result from haploinsufficiency of multiple X chromosomal genes (e.g., short stature homeobox, SHOX). However, imprinted genes also may be affected when the inherited X has different parental origins.# CLINICAL FEATURES- TS is characterized by bilateral streak gonads, primary amenorrhea, short stature, and multiple congenital anomalies in phenotypic females. It affects 1 in 2500 women and is diagnosed at different ages depending on the dominant clinical features. Prenatally, a diagnosis of TS usually is made incidentally after chorionic villus sampling or amniocentesis for unrelated reasons such as advanced maternal age. Prenatal ultrasound findings include increased nuchal translucency. The postnatal diagnosis of TS should be considered in female neonates or infants with lymphedema, nuchal folds, low hairline, or left-sided cardiac defects and in girls with unexplained growth failure or pubertal delay. The vast majority of women with TS develop complete ovarian failure.# Treatment:- Individuals with congenital heart defects (CHDs) (30%) (bicuspid aortic valve, 30-50%; coarctation of the aorta, 30%; aortic root dilation, 5%) require long-term follow, antibiotic prophylaxis for dental or surgical procedures, and serial imaging of aortic root dimensions, as progressive aortic root dilation is associated with increased risk of aortic dissection.- Individuals found to have congenital renal and urinary tract malformations (30%) are at risk for urinary tract infections, hypertension, and nephrocalcinosis. Hypertension can occur independently.- Clitoral enlargement or other evidence of virilization suggests the presence of covert, translocated Y chromosomal material and is associated with increased risk of gonadoblastoma, apparently as a consequence of Y chromosomal genes distinct from SRY.Autoimmune hypothyroidism (15-30%) can occur in childhood.- The treatment of short stature in children with TS remains a challenge, as untreated final height rarely exceeds 150 cm in nonmosaic 45,X TS. High-dose recombinant growth hormone stimulates growth rate in children with TS and may be used alone or in combination with low doses of the nonaromatizable anabolic steroid oxandrolone (up to 0.05 mg/kg per d) in an older child (>9 years).- Most physicians now choose to initiate low-dose estrogen therapy.
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