Truncations of titin causing dilated cardiomyopathy

Area of Science:

• Genetics
• Cardiology
• Molecular Biology

Background:

• Dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM) are linked to numerous gene mutations.
• The TTN gene, encoding titin, is large and has been underexplored for cardiomyopathy-associated mutations.

Purpose of the Study:

• To investigate the role of TTN gene mutations in dilated cardiomyopathy and hypertrophic cardiomyopathy.
• To determine the frequency and clinical significance of TTN mutations in these cardiomyopathies.

Main Methods:

• Analyzed TTN gene in 312 DCM, 231 HCM patients, and 249 controls using next-generation or dideoxy sequencing.
• Evaluated deleterious variants for cosegregation in families and assessed clinical characteristics.

Main Results:

• Identified 72 unique TTN mutations affecting full-length titin.
• TTN mutations were significantly more frequent in DCM (27%) than in HCM (1%) or controls (3%).
• TTN mutations cosegregated with DCM in families with high penetrance after age 40; mutations were overrepresented in the titin A-band.

Conclusions:

• TTN truncating mutations are a common cause of DCM, found in approximately 25% of familial and 18% of sporadic cases.
• Integrating TTN mutation detection into genetic testing can enhance DCM diagnosis and facilitate earlier therapeutic intervention.
• Further research into the functional impact of TTN mutations will deepen the understanding of DCM pathophysiology.