Table 6.

Clinical features of participants with mtDNA pathogenic variants vs nDNA pathogenic variants (total 110)

Characteristics	mtDNA (total 72)	nDNA (total 38)	P value
Age at onset			< 0.001^b
At birth to < 1 month	1 (1.4%)	7 (18.4%)
1 month to < 2 years	12 (16.7%)	20 (52.6%)
2 years to < 5 years	6 (8.3%)	3 (7.9%)
5 years to < 12 years	16 (22.2%)	5 (13.2%)
12 years to < 18 years	11 (15.3%)	1 (2.6%)
18 years or older	26 (36.1%)	2 (5.3%)
Sex			0.515^a
Male	37 (51.4%)	22 (57.9%)
Female	35 (48.6%)	16 (42.1%)
Organ system involvement at disease onset
Neurological	55 (76.4%)	33 (86.8%)	0.192^a
Hearing	10 (13.9%)	2 (5.3%)	0.212^b
Endocrine	9 (12.5%)	0	0.026^b
Gastrointestinal	5 (6.9%)	3 (7.9%)	1^b
Cardiac	1 (1.4%)	4 (10.5%)	0.048^b
Renal	4 (5.6%)	0	0.296^b
Eyes	2 (2.8%)	1 (2.6%)	1^b
Hematology	1 (1.4%)	0	1^b
Syndromic vs non-syndromic			< 0.001^a
Syndromic	67 (93.1%)	8 (21.1%)
Non-syndromic	5 (6.9%)	30 (78.9%)

mtDNA mitochondrial DNA, nDNA nuclear DNA

^aStatistical analysis performed by Pearson’s Chi-Square test

^bStatistical analysis performed by Fisher’s exact test