Clinical heterogeneity in families with multiple cases of inborn errors of immunity.

Background: Inborn errors of immunity (IEI) are a diverse range of genetic immune system illnesses affecting the innate and/or adaptive immune systems. Variable expressivity and incomplete penetrance have been reported in IEI patients with similar clinical diagnoses or even the same genetic mutation.

Methods: Among all recorded patients in the national IEI registry, 193 families with multiple cases have been recognized.