Screening for mutations in the ISL1 gene in patients with thyroid dysgenesis

Congenital hypothyroidism (CH) is a common endocrine disorder with an incidence of 1:3000- 4000 newborns. In 80-85% of cases, CH is caused by defects in thyroid organogenesis, resulting in absent, ectopically located, and/or severely reduced gland, all conditions indicated as "thyroid dysgenesis" (TD). A higher prevalence of congenital heart diseases has been documented in children with CH compared to the general population. This association suggests a possible pathogenic role of genes involved in both heart and thyroid development. Among these, it can be included Isl1, a transcription factor containing a LIM homeodomain that is expressed in both thyroid and heart during morphogenesis.

In the present study, we investigate the role of ISL1 in the pathogenesis of TD.

By single stranded conformational polymorphism, we screened for mutations the entire ISL1 coding sequence in 96 patients with TD and in 96 normal controls.

No mutations have been found in patients and controls.

Our data indicate that, despite the relevant role of ISL1 in thyroid and heart morphogenesis, mutations in its coding region are not associated with TD in our group of patients.