FAM199X

FAM199X, also known as CXorf39, is a gene located on the X chromosome that encodes a protein known as FAM199X.^[1] This gene is expressed in most vertebrates, including most mammals, birds, amphibians, and fish.^[2] Within humans, this gene is commonly expressed in the brain and thyroid.^[2] The gene has been linked to some genetic disorders, such as Pelizaeus–Merzbacher disease, and some cancers, such as Stomach cancer, but FAM199X's role in those diseases is not yet well understood within the scientific community.^[3]

Location of FAM199X on the X chromosome.

Molecular entity

Gene

FAM199X, also known as CXorf39, is located on the long arm of the X chromosome at Xq22.2 on the plus strand between bases 104,166,453 and 104,195,902 and encodes six exons.^[1][3] The gene is located next to an enhancer called LOC130068517, also known as ATAC-STARR-Seq Lymphoblastoid Active Region 29826.^[4]

Transcript

Four transcript variants of FAM199X produce two protein isoforms. The four transcript variants are FAM199X-X1 with 7498 nucleotides, FAM199X-X1 with 7495 nucleotides, FAM199X-X2 with 7179 nucleotides, and FAM199X-X1 with 7171 nucleotides.^[5] There are six exons in FAM199X-X1 variants and five exons in FAM199X-X2 variants.^[1]

Protein

There are two protein isoforms of FAM199X, FAM199X-X1 and FAM199X-X2.^[6] FAM199X-X1 is 345 amino acids long and 38.61kDa, and FAM199X-X2 is 205 amino acids long and 22.8kDa.^[6][7]

Homologs

FAM199X had several highly conserved orthologs amongst mammals, birds, reptiles, amphibians, fish, and less conserved orthologs in chorodates and arachnids. The most distant ortholog detected is the Branchiostoma floridae, a chordate.^[8]