Table 1.

Summary of Newcastle patient cohort and available data in literature

	With NMDAS	Without NMDAS	Our cohort (Total)	Meta-analysis
Number of patients with mitochondrial DNA deletion size and muscle mitochondrial DNA heteroplasmy data	55	32	87	256
Number of patients with mitochondrial DNA breakpoints identified	52	31	83	184
Number of patient with age at onset data	52	8	60	117
Number of patients with age at onset data and mitochondrial DNA breakpoints identified	49	7	56	83
Number of patients with COX-deficient fibre density data and mitochondrial DNA breakpoints identified	49	23	72	40
Number of patients presenting with a CPEO, CPEO + myopathy or KSS phenotype	36	27	63	205
Number of patients presenting with a CPEO, CPEO + myopathy or KSS phenotype and mitochondrial DNA breakpoints identified	35	26	61	149

All patients have skeletal muscle heteroplasmy and deletion size data available. Where gene location is under investigation the sub-cohort of patients with identified mitochondrial DNA breakpoints is used; where location is not under consideration, the larger cohort with mitochondrial DNA deletion size is used. The small cohort of patients with phenotype data reflects the fact that patients with a multisystem phenotype are excluded from the phenotype analysis, so this number is restricted to patients with CPEO, CPEO + myopathy, or Kearns-Sayre (KSS) syndrome. The patients with NMDAS data available had a median of five assessments (interquartile range 5).