Transient congenital hypothyroidism - too short to be transient

Congenital hypothyroidism (CH) occurs due to thyroid dysgenesis, thyroid ectopy, and dyshormonogenesis. A proportion of CH is transient which might be due to iodine deficiency/excess or maternal antibody-mediated. Certain forms of dyshormonogenetic defects may cause transient hypothyroidism. Here is a report of a neonate with overt clinical and biochemical hypothyroidism, who on evaluation was found to have dyshormonogenesis with a homozygous mutation in dual oxidase 2 (DUOX2) gene. During infancy, she became euthyroid. Severe in utero deficiency of thyroid hormone, very short duration of hypothyroidism and first-reported mutation of the DUOX2 gene in the Indian subcontinent were interesting features in this infant.