Causes of mental retardation in congenital hypothyroidism is -

Ans. is 'a' i.e., Decrease cerebral growth o Thyroid hormone has major effect on brain in utero & neonatal period, deficiency cause diminsh axonal growth, dendritic arborisation, delay proliferation & migration of granule cell so it decrease cerebral growth.Note Thyroid also decrease secretion GH from anterior pituitary but it cause growth retardation.Congenital hypothyroidismIt is very imp. preventable cause of mental retardation. So it is important to diagnose as early as possible. So neonatal screening is done for early diagnosis.C/F-o Open posterior fontanelle.o Umbilical hernia,o Edematous characteristics facies,o Constipation:PallorHypothermiaLarge protruded tongueRough dry skinHypotoniaLarge abdomen