Autosomal recessive
Caused by loss of function of both copies of BCKDK, an enzyme that normally switches off the breakdown of the branched-chain amino acids leucine, isoleucine and valine. Without it these amino acids are broken down continually, so blood levels are low.
Signs and symptoms
Developmental delay, intellectual disability and autism are the main features, sometimes with seizures or epilepsy. Low levels of branched-chain amino acids are found in blood tests. Most people develop a small head size over time, and many have impaired gross motor function.
What a diagnosis changes
Supplementing branched-chain amino acids and increasing dietary protein can raise blood levels, and early treatment has been reported to improve some features. Care is led by a metabolic team alongside developmental and seizure management. Carrier testing of relatives and genetic counselling are available.
Genes analysed
Also known as
autism - epilepsy syndrome due to branched chain ketoacid dehydrogenase kinase deficiency; BCKDKD
