Congenital Hypothyroidism due to Oligogenic Mutations in Two Sudanese Families.

Dyshormonogenic congenital hypothyroidism (CH) generally results from biallelic defects in thyroid hormone synthesis genes. Whole exome sequencing allows easier identification of multiple gene defects. Two Sudanese families with CH resulting from oligogenic defects identified by whole exome sequencing are presented. In family 1, the proposita with CH and goiter was heterozygous for three TPO, one TG, and one DUOX2 mutations, including three novel variants inherited from both parents. In family 2, two brothers with psychomotor delay and goiter were homozygous for digenic mutations in the DUOX2 and DUOX1 genes, while their asymptomatic parents were heterozygous. Accumulation of pathogenic mutations may contribute to CH.