While there are currently no validated biochemical markers to identify individuals with HAE-nC1INH, novel assays for assessing C1INH function and measurement of kinins or stimulated kallikrein activity (eg, dextran sulfate, cold induced) may potentially fulfill the crucial need to identify and diagnose HAE-nC1INH.1 The gene discussed is KLK4; the disease is hereditary angioedema.