major facilitator superfamily domain containing 8

The MFSD8 gene provides instructions for making a protein whose function is unknown. The MFSD8 protein is found in cell compartments called lysosomes, which digest and recycle different types of molecules. The MFSD8 protein belongs to a large group of related proteins called the major facilitator superfamily of secondary active transporter proteins. Proteins in this family move certain molecules between structures in cells or in and out of cells. While it is likely that the MFSD8 protein transports molecules, the specific molecules it moves are unknown. The MFSD8 protein probably transports substances across the membranes of lysosomes.

More than 30 mutations in the MFSD8 gene have been found to cause late-infantile neuronal ceroid lipofuscinosis (NCL). This condition impairs motor and mental development beginning in early childhood, causing movement disorders and a decline in intellectual function. In addition, affected children often develop recurrent seizures (epilepsy) and vision impairment. The MFSD8 gene mutations that cause late-infantile NCL result in the production of a protein with decreased or altered function. In the Roma population of the Czech Republic, one MFSD8 gene mutation is responsible for almost all cases of late-infantile NCL. This mutation replaces the protein building block (amino acid) threonine with the amino acid lysine at position 294 in the MFSD8 protein (written as T294K).

Fatty substances called lipopigments accumulate in the lysosomes of people with late-infantile NCL. These accumulations can result in cell dysfunction and eventually cause cell death, especially in brain cells, which are particularly vulnerable to damage caused by lipopigments. However, it is unclear how mutations in the MFSD8 gene are involved in the buildup of lipopigments and the signs and symptoms of late-infantile NCL.

Cytogenetic Location: 4q28.2, which is the long (q) arm of chromosome 4 at position 28.2

Molecular Location: base pairs 127,917,805 to 127,965,984 on chromosome 4 (Homo sapiens Annotation Release 108, GRCh38.p7) (NCBI)

Cytogenetic Location: 4q28.2, which is the long (q) arm of chromosome 4 at position 28.2
  • ceroid-lipofuscinosis neuronal protein 7
  • CLN7
  • major facilitator superfamily domain-containing protein 8
  • MGC33302