Lastly, genetic testing is part of the routine assessment for CVID patients but not for sarcoidosis, since patients with a CVID-like phenotype may present underlying genetic defects that might explain the reason for immune dysregulation, as well as represent an important clue for a tailored treatment approach in specific cases (e.g., CTLA-4 haploinsufficiency, LRBA deficiency) [65,66]. The gene discussed is CTLA4; the disease is sarcoidosis.