CNV in FCGR3A. (A) MLPA electropherogram. Individual A with only 1 allele FCGR3A (gray line) compared with individual B with 2 alleles of FCGR3A (black line). FCGR3A-specific probes are indicated with an arrow. As an example, 2 of the control probes are indicated (C). One of the probes is specific for the X-chromosome (X). Individual A: Female, FCGR3B-Na1Na1, FCGR3A-158F. Individual B: Male, FCGR3B-Na2Na2, FCGR3A-158FF. (B) MLPA electropherogram. Individual C with 3 alleles FCGR3A (gray line) compared with individual D with 2 alleles of FCGR3A (black line). FCGR3A-specific probes are indicated with an arrow. As an example, 2 of the control probes are indicated (C). One of the probes is specific for the X-chromosome (X). Individual C: Female, FCGR3B-Na2Na2, FCGR3A-158VFF. Individual D: Female, FCGR3B-Na2Na2, FCGR3A-158VF. Because of the homology between certain probes, probes had to be divided over 2 separate mixes to prevent competition.