The participant, a 31 year old female, reported lip and tongue angioedema, without wheals, which did not respond to treatment with steroids or antihistamines.<h4>Conclusions</h4>The genotype-first approach demonstrated that detection of PLG K330E in undiagnosed or misdiagnosed individuals can identify patients actually affected with HAE-U. This evidence concerns the gene PLG and hereditary angioedema.