Mutations of the NKX2.1 gene, previously known as TTF1 (thyroid transcription factor 1, OMIM*600635), mapping on chromosome 14q13, have been identified and associated with a syndromic form of CH (OMIM*610978) [2], initially named brain-lung-thyroid syndrome [3] due to the broad phenotypic spectrum including a variable combination of lung, thyroid and neurological defects. The gene discussed is NKX2-1; the disease is cyclic hematopoiesis.