Screening for Plasminogen Mutations in Hereditary Angioedema Patients

Area of Science:

• Genetics
• Immunology
• Rare Diseases

Background:

• Hereditary angioedema (HAE) involves recurrent swelling episodes and is often bradykinin-mediated.
• While most HAE cases stem from C1-inhibitor (C1-INH-HAE) gene mutations, seven other HAE types are known, including those linked to plasminogen (PLG-HAE).
• Hereditary angioedema of unknown origin (U-HAE) represents a diagnostic challenge.

Purpose of the Study:

• To investigate the genetic basis of hereditary angioedema of unknown origin (U-HAE).
• To identify novel gene mutations contributing to HAE phenotypes.
• To demonstrate the utility of biorepositories for ex-post genetic analysis in rare diseases.

Main Methods:

• DNA samples from 124 U-HAE patients were sequenced for exon 9 of the plasminogen (PLG) gene.
• Genetic analysis was performed on stored patient samples.
• Family screening was conducted upon identifying a mutation.

Main Results:

• A novel PLG gene mutation (K330E) was identified in one U-HAE patient.
• This specific PLG mutation was subsequently confirmed in the patient's son.
• The study highlights the successful application of advanced genetic testing on stored samples.

Conclusions:

• Biorepositories are crucial for ex-post analysis of newly identified genes in stored DNA.
• This approach enhances diagnostic accuracy for hereditary angioedema.
• Accurate diagnosis allows for targeted family screening and appropriate therapeutic interventions.