Definition

The BCKDHA gene encodes the E1α subunit of the branched-chain α-keto acid dehydrogenase (BCKD) complex; this mitochondrial complex carries out the key step in the catabolism of leucine, isoleucine and valine. Enzyme deficiency leads to the accumulation of toxic metabolites; the classic neonatal form presents with poor feeding, lethargy, urine with a characteristic maple syrup odor, encephalopathy and, if untreated, death; milder intermediate, intermittent and thiamine-responsive forms also exist.

Gene/region analyzed

BCKDHA - Exon 1, BCKDHA - Exon 2, BCKDHA - Exon 3, BCKDHA - Exon 4, BCKDHA - Exon 5, BCKDHA - Exon 6, BCKDHA - Exon 7, BCKDHA - Exon 8, BCKDHA - Exon 9

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Hereditary, autosomal recessive (AR).

Related Tests

Inheritance Patterns

Describes how a genetic condition is passed on within a family. There are five main patterns

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Carrier (Heterozygous / Homozygous)

Why it matters: In autosomal recessive inheritance, when each parent is a carrier (while both appear healthy), the chance of their child being born with the disease is 25% in each

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VUS (Variant of Uncertain Significance)

This is the situation where the test has detected a change in the DNA, but the role of this change in the development of disease is unconfirmed.

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How to Read a Genetic Test Result (Positive / Negative / VUS)

A genetic test result falls into three main categories

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Types of Genetic Tests

A genetic test is a type of medical test that detects changes in genes, chromosomes or proteins. Today there are more than 77,000 genetic tests available.

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