The pathogenic gene screening in a Chinese familial dilated cardiomyopathy pedigree from Hubei

Area of Science:

• Genetics
• Cardiology
• Molecular Biology

Background:

• Dilated cardiomyopathy (DCM) is a significant cause of heart failure, often linked to genetic mutations.
• The TTN gene, encoding the giant sarcomere protein titin, is a major contributor to DCM but is challenging to analyze due to its large size.
• Previous studies have suggested TTN as a key gene in familial DCM, yet comprehensive analysis remains limited.

Purpose of the Study:

• To investigate the role of TTN gene mutations in a Chinese family presenting with familial dilated cardiomyopathy.
• To identify specific genetic variants within the TTN gene associated with DCM in the studied cohort.
• To understand the clinical manifestation and genetic basis of DCM in this family.

Main Methods:

• Whole-exome sequencing or targeted gene sequencing of TTN in affected and unaffected family members.
• Polymerase chain reaction (PCR)-based sequencing of all coding exons and adjacent intronic regions of the TTN gene.
• Segregation analysis to confirm the inheritance pattern of identified mutations within the family.

Main Results:

• A novel missense mutation, c.100126A>G (p.Thr33376Ala), was identified in the TTN gene in two affected family members.
• The proband (III3) exhibited decreased cardiac function and malignant arrhythmia, while his sister (III2) remained asymptomatic with normal cardiac function.
• The identified TTN mutation was found to segregate with the disease within the family, indicating a strong genetic link.

Conclusions:

• The TTN gene is a crucial causative gene for familial dilated cardiomyopathy.
• The identified TTN missense mutation (c.100126A>G) is strongly associated with the development of DCM and its clinical phenotypes.
• This study underscores the importance of comprehensive TTN gene analysis in diagnosing and understanding familial DCM.