SLC5A1 and familial thyroid dyshormonogenesis: The vertebrate SLC5A family includes at least 12 members (SLC5A1–SLC5A12), mutations which are associated with human pathologies, including glucose–galactose malabsorption (SLC5A1, Xin & Wang, 2011), renal glucosuria (SLC5A2, van den Heuvel et al., 2002), thyroid dyshormonogenesis (SLC5A5, Kosugi et al., 1998), infantile‐onset biotin‐responsive neurodegeneration (SLC5A6, Byrne et al., 2019), and distal hereditary motor neuronopathy VIIA (SLC5A7, Barwick et al., 2012).