Creatine transporter deficiency (CTD) is an X‐linked metabolic disorder characterized by cerebral creatine (Cr) deficiency and affects approximately 1% of males diagnosed with non‐syndromic mental disability.1 Mutations in the SLC6A8 gene impair Creatine Transporter 1 (CT1)‐mediated transport of Cr from the blood circulation into cells.1 Currently, there are no available therapies for CTD, and supplementation with Cr has not been effective due to the lack of functional CT1 in these patients. Here, SLC6A8 is linked to X-linked creatine transporter deficiency.