2-Methylbutyryl-CoA dehydrogenase deficiency
Encyclopedia
2-Methylbutyryl-CoA dehydrogenase deficiency, also called 2-Methylbutyryl glycinuria or short/branched-chain acyl-CoA dehydrogenase deficiency (SBCADD), is an autosomal
recessive metabolic disorder. It causes the body to be unable to process the amino acid
isoleucine
properly.
and epilepsy
.
The disorder is caused by a mutation
in the ACADSB
gene
, located on the long arm of human chromosome 10
(10q25-q26). It is inherited in an autosomal recessive manner. This means the defective gene responsible for the disorder is located on an autosome
(chromosome 10 is an autosome), and two copies of the defective gene (one inherited from each parent) are required in order to be born with the disorder. The parents of an individual with an autosomal recessive disorder both carry
one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder.
Autosome
An autosome is a chromosome that is not a sex chromosome, or allosome; that is to say, there is an equal number of copies of the chromosome in males and females. For example, in humans, there are 22 pairs of autosomes. In addition to autosomes, there are sex chromosomes, to be specific: X and Y...
recessive metabolic disorder. It causes the body to be unable to process the amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
isoleucine
Isoleucine
Isoleucine is an α-amino acid with the chemical formula HO2CCHCHCH2CH3. It is an essential amino acid, which means that humans cannot synthesize it, so it must be ingested. Its codons are AUU, AUC and AUA....
properly.
Signs and symptoms
Untreated SBCADD can lead to progressive loss of motor skills, mental retardationMental retardation
Mental retardation is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors...
and epilepsy
Epilepsy
Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...
.
Cause and genetics
The disorder is caused by a mutation
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
in the ACADSB
ACADSB
ACADSB is a human gene that encodes short/branched chain specific acyl-CoA dehydrogenase , an enzyme in the acyl CoA dehydrogenase family.It can cause short/branched-chain acyl-CoA dehydrogenase deficiency.-References:...
gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
, located on the long arm of human chromosome 10
Chromosome 10 (human)
125px|rightChromosome 10 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 10 spans about 135 million base pairs and represents between 4 and 4.5 percent of the total DNA in cells.Identifying genes on each chromosome is an active area...
(10q25-q26). It is inherited in an autosomal recessive manner. This means the defective gene responsible for the disorder is located on an autosome
Autosome
An autosome is a chromosome that is not a sex chromosome, or allosome; that is to say, there is an equal number of copies of the chromosome in males and females. For example, in humans, there are 22 pairs of autosomes. In addition to autosomes, there are sex chromosomes, to be specific: X and Y...
(chromosome 10 is an autosome), and two copies of the defective gene (one inherited from each parent) are required in order to be born with the disorder. The parents of an individual with an autosomal recessive disorder both carry
Genetic carrier
A genetic carrier , is a person or other organism that has inherited a genetic trait or mutation, but who does not display that trait or show symptoms of the disease. They are, however, able to pass the gene onto their offspring, who may then express the gene...
one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder.