279- What are the learning disabilities which are present in patients with Turner
syndrome?
Patients with TS have preserved intellectual function and verbal abilities with
mild impairment in visuospatial, executive, and social cognitive domains. This
is reflected as poor sense of direction, difficulty in learning to drive, ability to
plan and execute tasks, arithmetic skills, and subtle defects in social behavior.
In addition, patients with ring chromosome or marker chromosome have an
increased risk of mental retardation. Hence, neuropsychological testing should
be routinely performed.- What are the common autoimmune disorders in patients with TS?
The incidence of autoimmune disorders is twofold higher in patients with TS
and those with an isochromosome Xq have higher incidence of autoimmune
disorders as compared to patients with other chromosomal abnormalities.
The most common autoimmune disease is Hashimoto’s thyroiditis (30–
50 %). Despite the high prevalence of thyroid autoantibody positivity, overt
hypothyroidism is uncommon. Therefore, it is recommended that patients
with TS should be annually screened for Hashimoto’s thyroiditis. Other
autoimmune disorders associated with TS include celiac disease (4–6 %),
juvenile rheumatoid arthritis, Graves’ disease (2.5 %), vitiligo, and Crohn’s
disease.- Why are autoimmune disorders common in patients with TS?
Autoimmune disorders are common in patients with TS; however, the exact
mechanism remains elusive. X chromosome contains majority of genes
involved in immune regulation. Therefore, haploinsufficiency of these
genes has been proposed as one of the potential mechanisms for increased
risk of autoimmune disorders in TS. Turner syndrome is a meiotic nondis-
junctional chromosomal disorder and patients with other nondisjunctional
chromosomal abnormities (Down’s syndrome and Klinefelter’s syndrome)
are also predisposed to autoimmune diseases, thereby suggesting a role of
nondisjunctional chromosomal abnormalities in the pathogenesis of auto-
immune disorders.- Why do children with TS lack pubarche despite adrenarche?
Despite timely occurrence of adrenarche, children with TS do not develop
pubarche or develop it later as compared to normal girls. It is thought that pres-
ence of functioning ovaries is required to convert weaker adrenal androgens to
more potent androgens, thereby resulting in pubarche. This explains the absence8 Turner Syndrome