What are the genetic changes related to 2-methylbutyryl-CoA dehydrogenase deficiency ?
Mutations in the ACADSB gene cause 2-methylbutyryl-CoA dehydrogenase deficiency.  The ACADSB gene provides instructions for making an enzyme called 2-methylbutyryl-CoA dehydrogenase that helps process the amino acid isoleucine. Mutations in the ACADSB gene reduce or eliminate the activity of this enzyme. With a shortage (deficiency) of 2-methylbutyryl-CoA dehydrogenase, the body is unable to break down isoleucine properly. As a result, isoleucine is not converted to energy, which can lead to characteristic features of this disorder, such as lethargy and muscle weakness. Also, an organic acid called 2-methylbutyrylglycine and related compounds may build up to harmful levels, causing serious health problems.