Mutations in DHCR7, encoding the penultimate enzyme in the pathway (downregulated 1.46-fold in Piezo1 KO brains) underlie Smith–Lemli–Opitz syndrome (SLOS), which includes symptoms of microcephaly, mental developmental delay, and hearing impairment (Irons et al., 1993). This evidence concerns the gene PIEZO1 and Hearing impairment.