Figure 2.

Creatine transporter deficiency (CTD)-associated variants mapped onto a CRT1 topology. CRT1 adopts the common structural fold of SLC6 proteins with 12 transmembrane domains (TMs) and cytoplasmic N- and C-termini. Most of the reported sequence alterations in CTD cluster in the region encompassing TMDs 7 and 8. Only those variants with the ascertained clinical phenotypes are displayed on the topology. Sixteen mutations are known to be folding-deficient. Individual mutants vary in their response to the chemical chaperone 4-PBA.