GK and alternating hemiplegia of childhood: AHC manifests itself mainly in early infancy or in childhood and is caused by deletions or point mutations in the NR0B1 (DAX1) (dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1) gene (OMIM∗300473) (Figures 1(a)–1(c)) [1]. NR0B1 (DAX1) deletion may occur in isolation or as part of a contiguous gene deletion syndrome at Xp21 including the dystrophin gene (DMD) and the glycerol kinase gene (GK).