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Updated: Jun 2, 2026

Genotyping Single Nucleotide Polymorphisms in the Mitochondrial Genome by Pyrosequencing
Published on: February 10, 2023
Mitochondrial insertion-deletion polymorphism: role in disease pathology
Sreelatha Komandur1, Sambasivan Venkatasubramanian, Ravindra Varma Alluri
1Department of Genetics and Molecular Medicine, Kamineni Hospitals, L.B Nagar, Hyderabad, India.
Aim:
Mitochondrial DNA (mtDNA) sequence variations are associated with a number of human diseases. The 9-bp repeat sequence, CCCCCTCTA, in the intergenic region of MTCO2 and MTTK genes of the mtDNA has been extensively used in phylogenic studies. The sequence has been reported to be polymorphic in south-east Asians in isolated cases of mt diseases. This is the first systemic study identifying the role of insertion-deletion polymorphism in human disease.
Results:
A total of 241 patients including those with cardiomyopathy, ataxias, and idiopathic neurological disorders along with 100 controls were screened; 2.9% of patients showed a single repeat (deletion) and 4.14% had three repeats (insertion), whereas all the controls had two repeats (normal).
Conclusion:
This indicates that the 9-bp insertion-deletion repeat polymorphism plays a role in disease pathology, affecting the expression of the downstream genes of mtDNA and altering ATP generation.
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