A novel start codon variant in SMCHD1 from a Chinese family causes facioscapulohumeral muscular dystrophy type 2

Physical examination showed core signs of FSHD [Supplementary Figure 1, http://links.lww.com/CM9/A481], including facial muscle weakness and left-right asymmetry of scapular winging. [...]the patient was classified as category D1 according to the clinical comprehensive evaluation form (CCEF) and received an FSHD clinical score (CS) of 7 points. Additionally, this patient II.6 developed impaired vision in her left eye with a visual index of 40 cm at 42 years of age. Because both the results of serum aquaporin-4 and myelin oligodendrocyte glycoprotein-immunoglobulin G were negative, and MRI of the spinal cord showed no changes associated with long transverse myelitis, she received a second diagnosis of acute optic neuritis. According to the guidelines for the interpretation of sequence variants,[3] the c.1 A>G of SMCHD1 was considered as a loss-of-function mutation, which was strong evidence for pathogenicity. Muscle MRI of patients II.3 and II.6 demonstrated imaging changes consistent with asymmetric atrophy, and the manifestation of fat infiltration in the II.6 MRI was consistent with her histology. [...]muscle MRI may be useful to select a muscle for biopsy and could also be used in FSHD longitudinal studies with the advantage of being without risk, pain-free, and not limited by age and disease severity.