Endocrine Abstracts

Background: Thyroid disorders are the commonest endocrine disorder after diabetes in most of the populations worldwide. Though, hypothyroidism is extremely common in children, there is acute scarcity of genetic studies leading to improper screening and treatment protocols in developing countries. The aim of this ambitious study was to screen for NIS, DUOX2 and TPO mutations in south Indian children and adolescent patients with dyshormogenetic goiter (DH) and Hashimoto’s thyroiditis (HT) and to define the relationships between NIS, DUOX2 and TPO genotypes and clinical phenotypes.

Material and methods: Blood samples were collected from 20 patients with dyshormogenetic goiter (DH) and Hashimoto’s thyroiditis (HT). Genomic DNA was extracted from peripheral blood leucocytes. PCR and direct sequencing were used to analyse for NIS, DUOX2 and TPO genes. Detailed clinical, biochemical and follow-up data were recorded in a structured proforma. Subjects with hypothyroidism were treated with thyroxine replacement. Detailed genetic analysis with 142 SNP (single nucleotide peptides) and eight sets of primers were done.

Results: The age of the cohort was 11±4.5 (5–17) years. F:M ratio was 17:3. The type of hypothyroidism was overt and subclinical in 14 and six patients respectively. Family history of hypothyroidism was present in seven patients (35%). Genetic analysis shows that heterozygous NIS mutations were seen in five children with HT and in two children with DH. A homozygous mutation was picked up in a child with HT. No mutations were found in DUOX and TPO genes.

Conclusions: NIS gene mutations appears to be most prevalent mutations in HT and DH amongst South Indian children in this study. The iodine deficiency and ethnic factors may be responsible for this pattern. Further studies are needed to characterise hypothyroid phenotypes in children.