Latest audiograms of the three patients shown in <b>Figs. 1</b> and <b>2</b>.

<p>Patients 15 and 29 have become cochlear implant users. The HL threshold of patient 28 has still not changed.</p

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).

<p>F = female, M = male, yrs = years, NA = not applicable.</p><p>The subgroups of patients: I – multi-organ presentation, II - isolated hearing loss and III - asymptomatic are presented separately.</p

Characteristics of the patients carrying the m.3243A>G mutation patients 1–17 with multi-organ presentation (subgroup I), patients 18–29 with isolated hearing loss (subgroup II), and asymptomatic carriers 30–34 (subgroup III).

<p>Probands are shown in bold.</p><p>GC-MS = gas chromatography–mass spectroscopy; NMDAS = Newcastle Mitochondrial Disease Adult Scale; MGCA = 3-methylglutaconic aciduria; LA = lactic aciduria; HL = hearing loss; NP = not performed; NA = normal value; QoL = quality of life; CI = cochlear implant user; IMGP = increased mineralisation of globus pallidus; MCA = minimal cerebellar atrophy; MRS = magnetic resonance spectroscopy; MRS score: 0 = negative LA, 1 = uncertain LA, 2 = positive LA, 3 = strong LA.</p><p>C = cardiomyopathy; DM = diabetes mellitus; H = migraine; I = infertility; K = renal insufficiency; M = myopathy; N = peripheral neuropathy; RP = pigmentary degeneration of retina; S = stroke-like episodes; SS = short stature.</p><p>No HL = normal hearing.</p>*<p>Stress = hearing deterioration following stressful event; Aminogly = hearing deterioration following aminoglycoside administration; Noise = hearing deterioration following noise exposure; Pancreatitis = hearing deterioration following acute pancreatitis; Pregnancy = hearing deterioration after pregnancy.</p

The sequences of the primers M_F and M_R.

<p>The sequences of the primers M_F and M_R.</p

Heteroplasmy level of the m.3243A>G mutation in examined tissues.

<p>Above: the scores of patients with multi-symptomatic presentation (subgroup I). Below: the scores of patients with isolated hearing loss and asymptomatic carriers (subgroups II and III together).</p

Comparison of clinical status among all groups of patients (I, II and III) carrying m.3423A>G mutation: I = Multi-symptomatic subgroup, II = Isolated HL subgroup, III = Asymptomatic subgroup.

*<p>2 patients had only part 2 assessed.</p>**<p>11/12 patients were assessed.</p>***<p>probably false positive related to high score for quality of life (part 1) of two patients.</p><p>HL = hearing loss; NMDAS = Newcastle Mitochondrial Disease Adult Scale; MRS = magnetic resonance spectroscopy,</p><p>LA = lactic acidosis, MGCA = 3-methylglutaconic aciduria, MRI = magnetic resonance imaging; NA = not applicable.</p><p>GC-MS = Gas Chromatography–Mass Spectroscopy.</p><p>Degree of HL: mild HL<40 dB; moderate 41–70 dB; severe 71–90 dB; profound >91 dB.</p