High-resolution melting analysis (HRM) for mutational screening of Dnajc17 gene in patients affected by thyroid dysgenesis

Background: Congenital hypothyroidism is a frequent disease occurring with an incidence of about 1/1500 newborns/year. In about 75% of the cases, CH is caused by alterations in thyroid morphogenesis, defined "thyroid dysgenesis" (TD). TD is generally a sporadic disease but in about 5% of the cases a genetic origin has been demonstrated. Previous studies indicate that Dnajc17 as a candidate modifier gene for hypothyroidism, since it is expressed in the thyroid bud, interacts with NKX2.1 and PAX8 and it has been associated to the hypothyroid phenotype in mice carrying a single Nkx2.1 and Pax8 genes (double heterozygous knock-out). Purpose: The work evaluates the possible involvement of DNAJC17 in the pathogenesis of TD. Methods: High-resolution DNA melting analysis (HRM) and direct sequencing have been used to screen for mutations in the DNAJC17 coding sequence in 89 patients with TD. Results: Two mutations have been identified in the coding sequence of DNAJC17 gene, one in exon 5 (c.350A>C; rs79709714) and one in exon 9 (c.610G>C; rs117485355). The last one is a rare variant, while the rs79709714 is a polymorphism. Both are present in databases and the frequency of the alleles is not different between TD patients and controls. Conclusions: DNAJC17 mutations are not frequently present in patients with TD.