The m.3243A > G mutation load in hair follicles from different scalp regions of patients with MELAS.

Objective To investigate the mitochondrial DNA (mtDNA) mutation load in hair follicles from different scalp regions of patients with mitochondrial, encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS), compare the mutation load in different scalp regions, and analyze the difference in mutation load between scalp regions with lesion site in the brain and scalp regions without lesion site in the brain. Methods Seven MELAS patients with m.3243A > G mutations were studied. Hair follicles were obtained from 8 scalp regions (bilateral frontal, temporal, parietal and occipital lobes) of all patients and DNA was extracted. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed to detect the m.3243A > G mutation. Results The mean value of m.3243A > G mutation load in hair follicles from all patients was (60.57 ± 7.71)%. In different scalp regions, the mean mutation load was (61.30 ± 7.32)% in left frontal, (65.41 ± 5.85)% in right frontal, (59.80 ± 5.58)% in left temporal, (57.59 ± 14.47)% in right temporal, (62.46 ± 5.02)% in left parietal, (60.11 ± 7.11)% in right parietal, (59.70 ± 8.68)% in left occipital and (59.42 ± 6.28)% in right occipital regions, respectively. There was no significant difference in the m.3243A > G mutation load among different scalp regions (F = 0.537, P = 0.802). There was no significant difference in the mutation load between scalp regions corresponding lesion site of the brain and scalp regions incorresponding lesion site of the brain [(60.33 ± 8.70)% vs. (61.02 ± 6.52)%; t = 0.319, P = 0.751)]. Conclusions Hair follicles are convenient and noninvasive sampled tissue for detecting mtDNA mutations. There is no difference in the mutation load among different scalp regions. Furthermore, there is no difference between scalp regions corresponding lesion site of the brain and scalp regions incorresponding lesion site of the brain. [ABSTRACT FROM AUTHOR]