*4.1.1. Genetic tests*

It is crucial to understand that not all persons with mtDNA mutations will manifest the symptoms. Nuclear DNA and mtDNA mutation screening can be performed in the consented family, but the challenge remains that only a small proportion of these nDNA mutations have been identified. The presence of family history of maternal inheritance or multisystemic diseases will be important to note. Furthermore, mitochondrial genome screening can also be performed on the muscle sample [132].
