PHOX2B and sudden infant death syndrome: Genetic variants of proteins involved in central chemoreception were found in three SIDS cases, one in the transcription factor paired-like homeobox 2B (PHOX2B; new variant; c.353C>T; A118V), and two in the inwardly rectifying K+ channel 5.1 (KCNJ16; new variant; c.667G>T; A188S and rs766250689; c.409C>A; R137S).