RYR1 and congenital fiber-type disproportion myopathy: As a general rule, central core disease (CCD) is mainly caused by heterozygous missense mutations often affecting amino acids in the C-terminal pore-forming domain of RyR1, while the less common and phenotypically overlapping multi-minicore disease (MmD), centronuclear myopathy (CNM), and congenital fiber type disproportion (CFTD) arise from recessive missense, splice, and truncating mutations dispersed over the entire gene, and usually involve an earlier disease onset and more severe clinical features compared with CCD [32].