Pol III-related leukodystrophy is a disorder that affects the nervous system and other parts of the body. Leukodystrophies are conditions that involve abnormalities of the nervous system's white matter, which consists of nerve cells (neurons) covered by a fatty substance called myelin. Myelin insulates nerve fibers and promotes the rapid transmission of nerve impulses.

Pol III-related leukodystrophy is caused by mutations in the POLR3A or POLR3B gene. These genes provide instructions for making the two largest parts (subunits) of an enzyme called RNA polymerase III. This enzyme is involved in the production (synthesis) of ribonucleic acid (RNA), a chemical cousin of DNA. The RNA polymerase III enzyme attaches (binds) to DNA and synthesizes RNA in accordance with the instructions carried by the DNA, a process called transcription. RNA polymerase III helps synthesize several forms of RNA, including ribosomal RNA (rRNA) and transfer RNA (tRNA). Molecules of rRNA and tRNA assemble protein building blocks (amino acids) into working proteins; this process is essential for the normal functioning and survival of cells.

Pol III-related leukodystrophy is a rare disorder; its prevalence is unknown. More than 100 affected individuals have been described in the medical literature.

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Published Date: June 01, 2017
Published By: National Institutes of Health