Phosphofructokinase (PFK) in RBCs is a tetrameric protein made up of two types of subunits: muscle or M type subunits, and liver or L type subunits (58). The M type subunit is encoded by a gene on chromosome 1 (56). The L type PFK deficiency subunit is encoded by a gene located on chromosome 21.
https://www.sciencedirect.com/topics/neuroscience/phosphofructokinase