Table 6 Clinical features of participants with mtDNA pathogenic variants vs nDNA pathogenic variants (total 110)

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%)