Genetic investigations had earlier been performed with normal results in several of the patients, including G-banding, high-resolution Single-Nucleotide Polymorphism (SNP) array to look for genomic deletions and duplications, FMRI CGG repeat analysis, DMPK PCR, sequencing of multiple neuromuscular disease genes, screening for mitochondrial DNA sequence variants/deletions, and screening for inborn errors of metabolism. This evidence concerns the gene DMPK and neuromuscular disease.