ACAT1 gene

acetyl-CoA acetyltransferase 1

The ACAT1 gene provides instructions for making an enzyme that is found in the energy-producing centers within cells (mitochondria). This enzyme plays an essential role in breaking down proteins and fats from the diet. Specifically, it helps process isoleucine, an amino acid that is a building block of many proteins. This enzyme is also involved in processing ketones, which are molecules that are produced when fats are broken down in the body.

During the breakdown of proteins, the ACAT1 enzyme is responsible for a step in processing isoleucine. It converts a molecule called 2-methyl-acetoacetyl-CoA into two smaller molecules, propionyl-CoA and acetyl-CoA, that can be used to produce energy.

The ACAT1 enzyme carries out the last step in ketone breakdown (ketolysis) during the processing of fats. The enzyme converts a molecule called acetoacetyl-CoA into two molecules of acetyl-CoA, which can be used to produce energy. In the liver, the enzyme also carries out this chemical reaction in reverse, which is a step in building new ketones (ketogenesis).

More than 100 mutations in the ACAT1 gene have been identified in people with beta-ketothiolase deficiency. The condition usually appears before age 2 and causes episodes (called ketoacidotic attacks) of vomiting, dehydration and other health problems, which can lead to coma. Some of the genetic changes that cause beta-ketothiolase deficiency disrupt the normal function of the enzyme, while other mutations prevent cells from producing any functional enzyme.

A shortage of the ACAT1 enzyme prevents the body from processing proteins and fats properly. As a result, chemical byproducts called organic acids can build up to toxic levels in the blood. These substances may cause the blood to become too acidic (ketoacidosis) and can damage the body's tissues and organs, particularly in the nervous system. This damage likely underlies the episodes associated with beta-ketothiolase deficiency.

Cytogenetic Location: 11q22.3, which is the long (q) arm of chromosome 11 at position 22.3

Molecular Location: base pairs 108,116,705 to 108,148,822 on chromosome 11 (Homo sapiens Updated Annotation Release 109.20200522, GRCh38.p13) (NCBI)

Cytogenetic Location: 11q22.3, which is the long (q) arm of chromosome 11 at position 22.3
  • ACAT
  • acetoacetyl Coenzyme A thiolase
  • acetyl-Coenzyme A acetyltransferase 1
  • acetyl-Coenzyme A acetyltransferase 1 (acetoacetyl Coenzyme A thiolase)
  • MAT
  • methylacetoacetyl-Coenzyme A thiolase
  • T2
  • THIL