Finally, based on both the histological and the ultrastructural analysis of all muscle biopsies, the 48 RYR1-recessive patients were classified as follow: 26 (54%) patients with Dusty Core Disease (DuCD); 10 (21%) patients with Central Core Disease (CCD); 8 (15%) patients with Cores and Rods (C&R) and 5 (10%) with Type1 predominance “plus” (T1P+). This evidence concerns the gene RYR1 and Central core disease.