Cascade family screening is an effective tool to identify individuals with hereditary angioedema (HAE) that can improve clinical and psychological outcomes as well as reduce disease-related costs, according to a new study published in The Journal of Allergy and Clinical Immunology: In Practice. The authors of the study, therefore, recommend that all affected families undergo cascade family screening.

At-risk relatives of people with HAE are already advised to undergo family screening, but different countries have different recommendations and the efficacy of the approach has not been proven.

Here, a team of researchers from Hong Kong evaluated the efficacy and impact of cascade family screening for at-risk relatives of people with HAE. The researchers identified 179 such relatives, 64 of whom they could screen. Twenty-nine people were newly diagnosed with HAE, a little over half of whom had symptoms before the screening. 

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The researchers also reported a stronger trend toward higher diagnostic yield among first-degree relatives of people with the disease, although this was not statistically significant.

Read more about the diagnosis of hereditary angioedema

Among the people who were symptomatic, the proportion of complete annual remission, the reduction in yearly hospital admission due to angioedema, and the length of hospital stay were higher 1 year after screening.

The Hospital Anxiety and Depression Scale-anxiety scores and improved Angioedema Quality-of-Life scores were reduced for all participants.

The researchers also calculated that cascade family screening reduced hereditary angioedema-related costs by at least $153 per patient per year. 

Finally, screening using a C4 cut-off greater than that suggested led to superior sensitivity and specificity.

“A higher cut-off level for C4 is useful for screening, prior to C1 inhibitor antigen or function testing,” the researchers wrote. 


Wong JCY, Chiang V, Lam K, et al. Prospective study on the efficacy and impact of cascade screening and evaluation of HAE (CaSE-HAE). J Allergy Clin Immunol Pract. Published online August 11, 2022. doi:10.1016/j.jaip.2022.07.035