We intended then to identify the pathogenic defects in DBT, BCKDHA, or BCKDHB. Unfortunately, the diagnosis of MSUD could not be confirmed based on coding sequence analysis of the respective genes, although a new unreferenced heterozygote mutation, c.G742T (p.A248S), was identified in BCKDHB. Since a significant percentage of DBT pathogenic variants are deletions (both large and small)17, we cannot exclude a large deletion in this gene, even though the gene coverage for this patient was not significantly different from the other 14 samples analyzed. Here, BCKDHA is linked to maple syrup urine disease.