Hereditary angioedema with F12 mutation: factors modifying the clinical phenotype

Area of Science:

• Genetics and Molecular Biology
• Immunology
• Biochemistry

Background:

• Hereditary angioedema with normal C1 inhibitor (HAE) due to F12 gene mutations (FXII-HAE) is rare and presents with variable clinical symptoms.
• Understanding modifiers of FXII-HAE is crucial due to its unpredictable nature.

Purpose of the Study:

• To identify genetic and biological modifiers affecting the clinical phenotype of FXII-HAE.
• To analyze the relationship between disease severity and specific biological markers.

Main Methods:

• Clinical and biological data from 118 mutation carriers, 58 noncarrier relatives, and 200 healthy donors were analyzed.
• Disease severity was assessed based on edema frequency, location, and age of onset.
• Logistic regression and odds ratios were used to evaluate the predictive value of biological markers including C1Inh, C4, ACE, APP, and CPN.

Main Results:

• Kinin catabolism enzymes, specifically angiotensin-I-converting enzyme (ACE) and carboxypeptidase N/M (CPN), were significantly associated with FXII-HAE disease severity.
• ACE showed an inverse relationship with disease severity (OR = 0.36, P < 0.001).
• CPN also exhibited an inverse relationship with disease severity (OR = 0.58, P < 0.05).

Conclusions:

• FXII-HAE is influenced by modifiers, including kinin catabolism enzymes like ACE and CPN.
• These identified modifiers differ from those associated with C1 inhibitor deficiency-based HAE.
• The findings highlight novel pathways involved in FXII-HAE pathogenesis.