Interpretation of mitochondrial tRNA variants.

Area of Science:

• Genetics
• Molecular Biology
• Bioinformatics

Background:

• Mitochondrial transfer RNAs (mt-tRNAs) play a critical role in mitochondrial protein synthesis.
• Mitochondrial genetic variations, particularly in mt-tRNAs, can lead to various human diseases.
• Accurate interpretation of mt-tRNA variants is essential for clinical diagnosis and genetic counseling.

Purpose of the Study:

• To develop and validate criteria for interpreting the clinical significance of mitochondrial transfer RNA (mt-tRNA) variants.
• To establish a framework based on unique mitochondrial genetics and tRNA structure/function.

Main Methods:

• Developed interpretation rules using established pathogenic/benign variants from literature.
• Examined heteroplasmy correlations with phenotype, tissue distribution, and family data.
• Validated rules with new cases and applied them to classify novel mt-tRNA variants.

Main Results:

• 80.6% of previously reported pathogenic variants showed phenotypic correlation with heteroplasmy.
• Verified criteria reclassified 80.8% of variants of uncertain significance (VUS) to benign or likely benign.
• Among 97 novel variants, none met pathogenic criteria; 84.5% remained VUS, and 10.3% were likely pathogenic.

Conclusions:

• Established criteria provide a robust method for interpreting mt-tRNA variants.
• Correlations with heteroplasmy, tissue distribution, and predicted tRNA structure are key evidence.
• Accurate interpretation of mt-tRNA variants is crucial for clinical diagnosis and genetic counseling.