A unique missense variant (transcript 15, ENST00000413698.5, NM_001291845, g.50435959, c.416T>C, p.Val139Ala) affecting the first zinc finger of IKAROS was identified in the CVID-affected individual of Family C who had sinusitis, repeated severe pneumonia, and low levels of IgG and IgA. This evidence concerns the gene IKZF1 and susceptibility to pneumonia measurement.