Mitochondrial disease in a heteroplasmic MT DNA mutation causing mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) and leigh syndrome phenotypes

Case presentation: A six year-old female child presented in a tertiary hospital with an acute stroke-like event after a week of cerebelar, bulbar and pyramidal syndromes. She had past history of failure to thrive, since young age, and another three stroke-like events since she was 2 years old. The course of the disease was chronic with acute exacerbation with some recovery in between. Milestones of motor development were adequate, but she present speech delay and learning disabilities. She is the third child of a non-consanguineous healthy couple. Mother's second gestation the child had unique multicystic kidney disease and died within five hours after being born. No family history of neurologic disease was reported. During investigation she was submitted to neuroimage with identification of stroke-like acute and past events, compared with previous images, and showed symmetrical hyperintense T2/FLAIR in striatum and putamen. Spectroscopy was normal. Cardiologic, auditory and visual investigations showed no additional findings. The cerebrospinal fluid showed slightly high lactate and cellularity and isolated herpes VI and VII-PCR. It was presumed that the infection was a trigger to the acute event, and therefore treated such, with ganciclovir. The acute event was treated with arginine and she had improvement mainly in bulbar symptoms.

Discussion: Genetic investigation showed mutation on MT ND 6 chr14.430 A > G, complex I in the respiratory chain, so far described once as a Leigh syndrome on a Chinese study. The percentage of heteroplasmic mutation on our patient was 78% on MT DNA on evaluated cells. We hereby describe a case of a recently described mutation on MT DNA but with a different phenotype, a patient with clinical stroke-like events, and neuroimage adding component of Leigh syndrome, despite the fact of the absence of movement disorders so far, neither epileptic events.

Final comments: Mitochondrial diseases has been a broad field for studies, with its different pattern of presentation, genetic mutations and mainly it's treatment's challenges. So far, some evidence has shown categorization of mitochondrial diseases into syndromes and directed treatment accordingly. The previous idea of mitochondrial cocktail is no longer seen as no doubtful plan. Arginine has been promising as a useful tool for stroke-like events, but it's still more evidence required.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
18 September 2023