DNMT3B and facioscapulohumeral muscular dystrophy: Thus, SMCHD1 and DNMT3B mutations have been associated with congenital diseases, whereas FSHD is an adult progressive disease with no congenital presentation, and very importantly, no FSHD patients carrying SMCHD1 mutations have signs of Bosma syndrome even when they carry overlapping missense mutations or mutations in the same regions of the coding sequence.