2.A.21.5.7
Sodium-dependent multivitamin transporter (Na⁺-dependent multivitamin transporter) (Solute carrier family 5 member 6) of 521 aas and 11 TMSs.  It transports biotin (vitamin B7), pantothenate (vitamin B5), α-lipoic acid, and iodide (Holling et al. 2022). Compound heterozygous SLC5A6 variants have been reported in individuals with variable multisystemic disorder, including failure to thrive, developmental delay, seizures, cerebral palsy, brain atrophy, gastrointestinal problems, immunodeficiency, and/or osteopenia. Holling et al. 2022 expanded the phenotypic spectrum associated with biallelic SLC5A6 variants affecting function by reporting five individuals from three families with motor neuropathies. Missense variants p.(Tyr162Cys) and p.(Ser429Gly) did not affect plasma membrane localization of the ectopically expressed multivitamin transporter, suggesting reduced function, such as lower catalytic activity (Holling et al. 2022).