GRIA1 and mean corpuscular hemoglobin concentration: Furthermore, we identified single-markers on SSC16 (glutamate ionotropic receptor AMPA type subunit 1(GRIA1), SSC4 (Fc receptor like 3 (FCRL3) and SSC14 (fibronectin type III and ankyrin repeat domains 1 (FANK1) associated with MCHC.