Related Experiment Video
Updated: Aug 30, 2026

Targeted Next-generation Sequencing and Bioinformatics Pipeline to Evaluate Genetic Determinants of Constitutional Disease
Published on: April 4, 2018
Exercise intolerance, muscle pain and lactic acidaemia associated with a 7497G>A mutation in the tRNASer(UCN) gene
O Grafakou1, F A Hol, K Otfried Schwab
1Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, University Medical Center Nijmegen, The Netherlands.
Abstract:
A 13-year-old girl with non-familial exercise intolerance, muscle pain and lactic acidaemia underwent a muscle biopsy for suspected mitochondrial disease. Muscle morphology showed 25% ragged-red fibres and 80% COX-negative staining. Enzymatic activities of mitochondrially co-encoded respiratory chain enzymes (complexes I, III, and IV) were decreased in muscle but normal in cultured skin fibroblasts. mtDNA analysis revealed the presence of the 7497G>A mutation in the tRNASer(UCN) gene, homoplasmic in skeletal muscle and 90% in leukocytes. Analysis of the mother's mtDNA showed 10% heteroplasmy in blood. It may be concluded that the 7497G>A mutation is associated with a muscle-only disease presentation for which high levels of mutated mtDNA are required. Exercise intolerance and muscle pain in otherwise normal children warrants further mitochondrial evaluation.
Related Concept Videos
Translation
Translation
Muscle Recovery and Fatigue
Cystic Fibrosis: Pathogenesis
CF is primarily caused by a genetic mutation in a chromosome 7 gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The most common gene mutation leading to CF is the ΔF508 mutation, but...
Alternative RNA Splicing
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase

