Novel homozygous variant in the TPO gene associated with congenital hypothyroidism and mild-intellectual disability

Congenital hypothyroidism (CH) is one of the most common hereditary disorders affecting neonates worldwide. CH is a multifactorial complex disorder and can be caused by either environmental factors or genetic factors. We studied one Pakistani family with segregating mutations in CH inherited in an autosomal recessive manner. Using whole-exome sequencing (WES), we found a novel homozygous missense variant (c.2315A>G; p.Tyr772Cys) in the thyroid peroxidase (TPO) gene. Different bioinformatics prediction tools and Sanger sequencing were performed to verify the identified variant. Our findings highlight the importance of this gene in causing CH and mild-intellectual disability (ID) in two affected brothers. WES is a convenient and useful tool for the clinical diagnosis of CH and other associated disorders.