The rarer FSHD2 form, which accounts for the remaining 5% of FSHD patients, has been attributed to variants in D4Z4 chromatin repressors, mainly occurring within the structural maintenance of the chromosomes flexible hinge domain-containing 1 (SMCHD1) gene encoding a chromatin remodeling factor important for DNA methylation [69,70]. The gene discussed is SMCHD1; the disease is facioscapulohumeral muscular dystrophy.