Deletion of NKX2.1 gene encoding thyroid transcription factor-1 in two siblings with hypothyroidism and respiratory failure

Thyroid transcription factor-1 encoded by the NKX2.1 gene is a candidate re gulator of thyroid and lung morphogenesis and function in humans, We report 2 female siblings with congenital thyroid dysfunction and recurrent acute respiratory distress carrying a heterozygous deletion of chromosome 14q12-1 3.3, resulting in haploinsufficiency for the NKX2.1 gene. This observation further supports a physiologic mle for thyroid transcription factor-1 in ea rly human thyroid and pulmonary function.