Sudden infant death syndrome is not associated with the mutation of PHOX2B gene, a major causative gene of congenital central hypoventilation syndrome.

Sudden infant death syndrome (SIDS) is a major cause of infant death, but its etiology is unknown. There are several independent risk factors for SIDS, and prone sleeping is a major risk factor. SIDS is probably based on a compromise in arousal response to breathing or blood pressure during sleep. Congenital central hypoventilation syndrome (CCHS or Ondine's curse) is a disorder characterized by an idiopathic failure of the autonomic control of breathing and has been regarded as one of the compromised conditions in SIDS. Recently, mutations of the PHOX2B gene have been detected in half to two-thirds of CCHS patients. We therefore analyzed the PHOX2B gene in 23 cases of SIDS and did not find any mutations, except for three polymorphic nucleotidic substitutions. The mutation of PHOX2B is thus not likely associated with SIDS.