Molecular diagnostics of mitochondrial disorders

Area of Science:

• Genetics
• Molecular Biology
• Biochemistry

Background:

• Mitochondrial respiratory chain (RC) disorders stem from nuclear and mitochondrial genes.
• Nuclear gene mutations are increasingly identified, but mtDNA mutations explain only 15-20% of pediatric cases.
• Genetic causes remain unknown for many patients, hindering diagnosis and research.

Purpose of the Study:

• To highlight the importance of elucidating genetic bases of RC disorders for diagnosis and fundamental knowledge.
• To discuss strategies for identifying disease-causing mutations in mitochondrial disorders.
• To address challenges in diagnosing sporadic cases.

Main Methods:

• Fine phenotyping and candidate gene screening for cohort creation.
• Genetic mapping, particularly effective in consanguineous families.
• Functional complementation using human chromosomes or cDNA for sporadic cases.

Main Results:

• Elucidating genetic bases is essential for both patient diagnosis and advancing fundamental knowledge.
• Identification of new genes aids diagnosis in other families and enables further functional studies.
• Specific strategies like genetic mapping and functional complementation are vital for different patient groups.

Conclusions:

• Identifying the genetic causes of RC deficiency requires diverse and appropriate strategies.
• A combination of phenotyping, gene screening, genetic mapping, and functional complementation is necessary.
• Functional complementation remains the primary strategy for sporadic cases with unknown genetic causes.