Co-inheritance of mutations associated with arrhythmogenic cardiomyopathy and hypertrophic cardiomyopathy

Area of Science:

• Cardiovascular Genetics
• Molecular Cardiology
• Genetic Basis of Cardiomyopathies

Background:

• Arrhythmogenic cardiomyopathy (ACM) and hypertrophic cardiomyopathy (HCM) are distinct genetic myocardial disorders.
• Genetic mutations are known causes for ACM and HCM individually.
• The implications of co-inheriting mutations for both conditions are not well understood.

Purpose of the Study:

• To investigate the co-inheritance of ACM and HCM-associated gene mutations in families with recurrent cardiomyopathies.
• To analyze the clinical presentation and phenotype of individuals with double heterozygous mutations.

Main Methods:

• Genetic analysis of two families with recurrent ACM and HCM.
• Identification of mutations in genes such as DSP, MYBPC3, CTTNA3, and MYH7.
• Clinical phenotyping and assessment against diagnostic criteria for ACM and HCM.

Main Results:

• Co-inheritance of DSP and MYBPC3 mutations in Family A, with affected individuals diagnosed with either ACM or HCM.
• Identification of CTTNA3 and MYH7 mutations in Family B, with one patient not meeting criteria for either cardiomyopathy.
• Variable clinical expression observed in double heterozygotes, without a consistently more severe phenotype compared to single mutation carriers.

Conclusions:

• This study presents the first evidence of co-inheritance of ACM and HCM-associated mutations.
• Double heterozygosity can lead to variable presentations, including diagnoses of ACM or HCM, or phenotypes not meeting current criteria.
• The clinical impact of co-inheriting these specific mutations requires further investigation, as severity is not uniformly increased.