Introduction: Leigh syndrome, caused by dysfunction in mitochondrial energy metabolism, is an inherited, heterogeneous and progressive neurodegenerative disorder in infancy and childhood. The aim of this study is to analyze the life expectancy in patients with Leigh syndrome from clinical and genetic features.

Methods: From 1983 to March 2012, 30 patients diagnosed with Leigh syndrome by characteristic neuroimaging findings, abnormal histochemical stains and/or abnormal mitochondrial configurations of the muscle cells, and/or pathognomonic mitochondrial gene mutations.

Results: 22 of 30 cases presented clinical features before age of one year. All of them presented with variable symptoms of CNS involvement. The first three common symptoms were developmental delay, seizures, and altered level of consciousness. Extra-CNS manifestations were not uncommon, including pericardial effusion, cardiac rhythm disorder, ophthalmologic disorder, hearing impairment, liver function impairment, and failure to thrive. All of them showed abnormal neuroimaging findings over the basal ganglia and/or brainstem. 12 cases carried mitochondrial gene mutations, i.e., seven were T8993G, three were T10191C, one was A8344G, and one was A4316G. The prognosis for Leigh syndrome was poor during long-term follow up. 18 cases died of sudden apnea or respiratory failure before 1 year and 6 months of age. Three cases with T10191C mutation manifested longer life expectancy. The longest age was 17 years old.

Conclusions: Patients with mitochondrial T10191C mutation had a longer life expectancy as compared with that of other gene mutations in patients with Leigh syndrome.