Table 1 Complexity of diagnostic genetic testing in major neuromuscular diseases
Phenotype | Gene | Molecular genetic testing methods | Proportion of probands with a pathogenic variant detectable | ||
|---|---|---|---|---|---|
Duchenne/Becker muscular dystrophy (DMD/BMD) | DMD | Sequence analysis | 20–35% | ||
Gene-targeted deletion/duplication analysis | 65–80% | ||||
Spinal muscular atrophy (SMA) | SMN1 | Sequence analysis | 2–5% | ||
Gene-targeted deletion/duplication analysis | 95–98% | ||||
Facioscapulohumeral muscular dystrophy (FSHD) | D4Z4 | Targeted analysis for pathogenic variants (pathogenic contraction of number of D4Z4 repeats) |  ~ 95% | ||
Methylation analysis |  ~ 5% | ||||
Myotonic dystrophy type 1 (DM1) | DMPK | Targeted analysis for pathogenic variants (testing to quantitate the number of DMPK CTG trinucleotide repeats) | 100% | ||
Fukuyama congenital muscular dystrophy | FKTN | Targeted analysis | Japanese | Non-Japanese Asian | Non-Asian |
c.*4392_*4393insAB185332.1 | 98% 3 | 77% 4, 5 | 0% | ||
c.647 + 2084G > A | 8% | 38% (Korean) | 0% | ||
c.139C > T | 7% | 60% (Chinese) | Rare | ||