Clinical presentation and inheritance are heterogenous and can be classified into three main groups: the most severe X-linked CNM (XLMTM, myotubular myopathy) caused by mutations in MTM1 encoding myotubularin (MTM1) [3]; autosomal dominant CNM (ADCNM) caused by dominant mutations in DNM2 encoding dynamin 2 (DNM2) [4] or in BIN1 encoding amphiphysin 2 (BIN1) [5]; and autosomal recessive CNM (ARCNM) caused by a mutation in BIN1 [6] or RYR1 encoding ryanodine receptor (RyR1) [7,8]. The gene discussed is RYR1; the disease is X-linked myotubular myopathy.