Autosomal recessive
Caused by changes in the ACADSB gene, which makes short/branched-chain acyl-CoA dehydrogenase, an enzyme in the breakdown of isoleucine. Reduced enzyme activity leads to a build-up of 2-methylbutyrylglycine and C5-acylcarnitine, which newborn screening detects.
Signs and symptoms
Most people identified through newborn screening have no symptoms. A small number of reported children have had developmental delay, low muscle tone or seizures, but it is not clear that the enzyme deficiency itself caused these features.
What a diagnosis changes
Many people need no treatment. Avoiding long periods without food, especially during illness, may help, as fasting and infections can trigger symptoms. Children are followed for development, and genetic counselling can be offered to relatives.
Genes analysed
Also known as
2-methylbutyric aciduria; 2-methylbutyrylglycinuria; butyryl-CoA dehydrogenase deficiency; developmental delay due to 2-methylbutyryl-CoA dehydrogenase deficiency; SBCAD deficiency; short branched-chain acyl-CoA dehydrogenase deficiency
