TPH2 and sudden infant death syndrome: Important advances in our understanding of potential pathophysiological mechanisms include careful examination and comparisons of brainstem tissues from SIDS and control infants, which led to the identification of reduced brainstem 5‐HT tissue levels and reduced brainstem tryptophan hydroxylase 2 (rate‐limiting enzyme in 5‐HT synthesis) levels among other findings (Bright et al., 2017; Duncan, 2010; Kinney, 2009; Kinney et al., 1983, 2001, 2003, 2005).