Low incidence of X-chromatin in congenital hypothyroidism.

Buccal smears of 5 female patients with hypothyroidism (3 with congenital hypothyroidism or cretinism and 2 with acquired type) were studied for X-chromatin. Very low incidence of X-chromatin positive cells (1.33%, 1.59% and 2.06%) was found in all the three cases with cretinism while the incidence was the same (15.0% and 15.61%) as in the control females (15.5%), in 2 cases with acquired hypothyroidism. Chromosome studies were carried out in two cases of cretinism. They had a normal karyotype, 46 XX.