Table 4.

mtDNA alterations in ALS.

Alteration Type	Observed Change	Analysis Method	Patient Sample	References
mtDNA deletion	↓mtDNA copy number	digital droplet PCR	Prefrontal Cortex in C9ALS/FTD	[237]
mtDNA deletion	↑mtDNA copy number but not statistically significant.	quantitative PCR	peripheral white blood cells	[172]
mtDNA methylation	↓D-loop region	Bisulfite pyrosequencing
mtDNA deletion	multiple mitochondrial DNA deletions	long range PCR and Southern blot analysis	muscle	[180]
	relative mtDNA copy number without finding any depletion	real-time quantitative PCR
mtDNA methylation	↓D-loop region (↑mtDNA copy number)	MS-HRM and quantitative PCR	blood samples	[173]

Abbreviations: C9ALS/FTD, amyotrophic lateral sclerosis and frontotemporal dementia with C9ORF72 mutation; PCR, polymerase chain reaction; D-loop, displacement-loop; MS-HRM, methylation-sensitive high-resolution melting.