Last but not least, the very high prevalence of CMC (98%) in STAT1 GOF should also be considered to be due to ascertainment bias, where, e.g., other dermatological manifestations such as eczematous dermatitis are misinterpreted as CMC, which could overestimate the prevalence of CMC in STAT1 GOF patients. Here, STAT1 is linked to atopic eczema.