Membrane-spanning 4A

Membrane-spanning 4A genes are members of the CD20-like family. The MS4A genes are usually organized in a single genomic clusters in mammals, suggestive of gene duplication events. MS4A genes encode a class of four-transmembrane spanning proteins. MS4A genes have been described to act as a specific kind of olfactory receptor in the necklace olfactory sensory neurons in mice (Mus musculus).

In human (Homo sapiens) the members of this family include:
 * MS4A1 (better known as "CD20")
 * MS4A2
 * MS4A3
 * MS4A4A
 * MS4A4E
 * MS4A5
 * MS4A6A
 * MS4A6E
 * MS4A7
 * MS4A8B
 * MS4A9
 * MS4A10
 * MS4A12
 * MS4A13
 * MS4A14
 * MS4A15
 * MS4A18