Biochemical, radiological, and genetic characterization of congenital hypothyroidism in Abu Dhabi, United Arab Emirates.

Background: Congenital hypothyroidism (CH) is caused by thyroid gland (TG) dysgenesis or inadequate thyroid hormone biosynthesis in a structurally normal gland. Different etiologies are known to be associated with various clinical, biochemical and imaging markers and a subset of cases have an underlying genetic basis. Despite the presence of neonatal screening programs in the UAE, there is a lack of data on the disease etiology in the area.

A deletion including exon 2 of the TSHR gene is associated with thyroid dysgenesis and severe congenital hypothyroidism.

Congenital hypothyroidism (CH) is the most common neonatal endocrine disorder and 2% of cases have a familial origin. Our aim in this study was to determine the genetic alterations in two siblings with CH coming from a consanguineous family. As CH is often inherited in an autosomal recessive manner in consanguineous/multi case-families, we first performed genetic linkage studies to all known causative CH loci followed by conventional sequencing of the linked gene.

Thyroid dyshormonogenesis is mainly caused by TPO mutations in consanguineous community.

Objective: In this study, we aimed to investigate the genetic background of thyroid dyshormonogenesis (TDH).

Context: Thyroid dyshormonogenesis comprises 10-15% of all cases of congenital hypothyroidism (CH), which is the most common neonatal endocrine disorder, and might result from disruptions at any stage of thyroid hormone biosynthesis. Currently seven genes (NIS, TPO, PDS, TG, IYD, DUOX2 and DUOXA2) have been implicated in the aetiology of the disease.