Fcgr3a Fc receptor, IgG, low affinity IV + O Gene FcgammaRIV|4833442P21Rik|Fcgr3a|CD16-2 http://identifiers.org/mgd/MGI:2179523 genetic mapping FcgammaRIV 4833442P21Rik CD16-2 protein coding gene MGI:2179523 Fcgr4