Targeted massively parallel sequencing and histological assessment of skeletal muscles for the molecular diagnosis of inherited muscle disorders.

BACKGROUND

Inherited skeletal muscle diseases are genetically heterogeneous diseases caused by mutations in more than 150 genes. This has made it challenging to establish a high-throughput screening method for identifying causative gene mutations in clinical practice.

AIM: In the present study, we developed a useful method for screening gene mutations associated with the pathogenesis of skeletal muscle diseases.

METHODS

We established four target gene panels, each covering all exonic and flanking regions of genes involved in the pathogenesis of the following muscle diseases: (1) muscular dystrophy (MD), (2) congenital myopathy/congenital myasthenic syndrome, (3) metabolic myopathy and (4) myopathy with protein aggregations/rimmed vacuoles. We assigned one panel to each patient based on the results of clinical and histological analyses of biopsied muscle samples and performed high-throughput sequencing by using Ion PGM next-generation sequencer. We also performed protein analysis to confirm defective proteins in patients with major muscular dystrophies. Further, we performed muscle-derived cDNA analysis to identify splice-site mutations.

RESULTS

We identified possible causative gene mutations in 33% of patients (62/188) included in this study. Our results showed that the MD panel was the most useful, with a diagnostic rate of 46.2%.

CONCLUSIONS

Thus, we developed a high-throughput sequencing technique for diagnosing inherited muscle diseases. The use of this technique along with histological and protein analyses may be useful and cost-effective for screening mutations in patients with inherited skeletal muscle diseases.