Screening of mitochondrial mutations in Tunisian patients with mitochondrial disorders: An overview study

Abstract

To investigate the spectrum of common mitochondrial mutations in Tunisia during the years of 2002–2012, 226 patients with mitochondrial disorders were clinically diagnosed with hearing loss, Leigh syndrome (LS), diabetes, cardiomyopathy, Kearns–Sayre syndrome (KSS), Pearson syndrome (PS), myopathy, mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes syndrome (MELAS) and Wolfram syndrome. Restriction fragment length polymorphism (PCR-RFLP), radioactive PCR, single specific primer-PCR (SSP-PCR) analysis and PCR-sequencing methods were used to identify the mutations. Two cases with m.1555A>G mutation and two families with the novel 12S rRNA m.735A>G transition were detected in patients with hearing loss. Three cases with m.8993T>G mutation, two patients with the novel m.5523T>G and m.5559A>G mutations in the tRNA^Trp gene, and two individuals with the undescribed m.9478T>C mutation in the cytochrome c oxidase subunit III (COXIII) gene were found with LS. In addition, one case with hypertrophic cardiomyopathy and deafness presented the ND1 m.3395A>G mutation and the tRNA^Ile m.4316A>G variation. Besides, multiple mitochondrial deletions were detected in patients with KSS, PS, and Wolfram syndrome. The m.14709T>C mutation in the tRNA^Glu was reported in four maternally inherited diabetes and deafness patients and a novel tRNA^Val m.1640A>G mutation was detected in a MELAS patient.

Keywords::

• Mitochondrial mutation
• deafness
• Leigh syndrome
• KSS
• Pearson syndrome
• diabetes

Acknowledgement

We thank all the patients and their families for their cooperation in the present study.

Declaration of interest: This work was supported by The Ministry of Higher Education and Scientific Research in Tunisia. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.