[3] The FOLR multi-gene family (FOLR1, FOLR2 and FOLR3) is localized to chromosome 11q13.3–q14.1, and encodes the gene products FRα, β and γ, respectively.

[4] FOLR3 is localized in haematopoietic tissue, such as spleen and bone marrow, and is present as a secretory protein.

[3] The FOLR3 gene is polymorphic due to a nonsense mutation resulting in a truncated protein; FRγ, which can bind folic acid.

FOLR3 genes each consist of 5 exons, 4 introns and 1 promoter that encodes a single transcript.

These results indicate that an increase in FOLR3 may effectively ameliorate Hcy in the blood and weaken Hcy-induced toxicity, even in tissues with the low level of FOLR1 and FOLR2 expression.