Dilated Cardiomyopathy due to the Novel MT-CYB Missense Mutation m.14757T>C

Area of Science:

• Genetics
• Cardiology
• Mitochondrial Biology

Background:

• Mitochondrial DNA (mtDNA) mutations are associated with multisystem disorders, including cardiomyopathy (CM).
• Mutations in protein-encoding mtDNA genes, like cytochrome-b, have been implicated in CM.
• Dilated cardiomyopathy (DCM) is a significant cardiac condition often requiring further etiological investigation.

Observation:

• A clinical, biochemical, and molecular genetic analysis was conducted on a 40-year-old male patient diagnosed with DCM.
• Muscle biopsy revealed a deficiency in complex-III activity.
• Genetic sequencing identified a novel variant, m.14757T>C, in the MT-CYB gene.

Findings:

• The identified MT-CYB variant (m.14757T>C) results in a methionine to threonine substitution (M4T) at position 4.
• Bioinformatic analysis using PolyPhen predicted the variant as pathogenic.
• This mutation was absent in 2,704 healthy controls and previously unreported as a neutral polymorphism, supporting its pathogenicity.

Implications:

• The novel MT-CYB variant m.14757T>C is associated with dilated cardiomyopathy.
• This discovery suggests a potential pathophysiological role for this specific mtDNA variant in the development of DCM.
• Further research into mitochondrial genetic defects can improve diagnosis and understanding of cardiomyopathies.