Table 4. Heteroplasmy levels (% of total tissue DNA) of m.3243A>G mutation in mtDNA samples isolated from: urinary sediment, hair follicles, buccal mucosa, nails and blood (put in order of heteroplasmy intensity).

No of patients in group; mean age	Females/Males	Gender-age of onset (mean age of onset in group)	No of studied samples of urinary sediment; Mean %; (Range %)	No of studied samples of hair follicles; Mean %; (Range %)	No of studied samples of buccal mucosa smear; Mean %; (Range %)	No of studied samples of nails; Mean %; (Range %)	No of studied samples of blood; Mean %; (Range %)
I group (17) 36 yrs	10/7	F–24 yrs; M–16 yrs (21 yrs)	13; 67%; (31.4%–96.5%)	13; 21.2%; (0%–77.2%)	11; 26.1%; (5.6%–60.2%)	12; 26.4%; (6.7%–65.2%)	14; 14,4%; (5,4%–27,8%)
II group (12) 40 yrs	8/4	F–37 yrs; M–23 yrs (32 yrs)	11; 51.5%; (7.6%–85.8%)	8; 25.8%; (1.6%–63.7%)	10; 21.0%; (1.2%–33.2%)	9; 14.2%; (1.8%–24.6%)	12; 9,3%; (0%–32,1%)
III group (5) 8 yrs	4/1	NA	3; 39.5%; (16.2%–81.3%)	4; 44.8%; (20.4%–66.5%)	5; 35.9%; (3.8%–100%)	4; 34.1%; (16.7%–49.6%)	5; 21,1%; (12,8%–32,5%)
Total 34 patients 33 yrs	22/12	F–28 yrs; M–18 yrs (26 yrs)	27; 57.6%; (7.6%–96.5%)	26; 26.5% (0%–77.2%)	26; 26.0%; (1.2%–100%)	25; 23.2%; (1.8%–65.2%)	31; 13,5%; (0%–32,5%)

F = female, M = male, yrs = years, NA = not applicable.

The subgroups of patients: I – multi-organ presentation, II - isolated hearing loss and III - asymptomatic are presented separately.