Patients with mitochondrial diseases followed up at an outpatient clinic in Belo Horizonte: a case series

Case presentation: In a referral hospital for rare diseases in Belo Horizonte, Minas Gerais, we followed up five patients with a molecular diagnosis of mitochondriopathies. A.E.S.V, 3 years and 11 months, diagnosed with Leigh Syndrome due to a homozygous point mutation in the NDUFAF5 gene, presented delayed onset of neuropsychomotor development associated with central characteristic hypotonia, difficult-to-control epilepsy and brain MRI with multiple nodular lesions in T2/FLAIR affecting brain parenchyma. M.R.M.R, 2 years and 2 months old, has a mutation in the POLG gene, and had as clinical presentation regression in neurodevelopmental milestones, difficult-to-control epilepsy, and orofacial dyskinesias, with unaltered brain MRI. H.R.R, 2 years old, with a point mutation in the NDUFS1 gene, presented at 9 months, regression in the neurodevelopmental milestones associated with spasticity and brain MRI showed an extensive area of signal hyperintensity in T2/Flair compromising subcortical and periventricular white matter bilaterally and symmetrically, with some areas of periventricular cystic degeneration. A.B.T.G, 11 years old, diagnosed with Leigh Syndrome due to a homozygous pathogenic mutation in the SURF1 gene (mitochondrial respiratory chain IV complex deficiency), presented dystonia and development regression at 1 year and 6 months. E.S.S, 15 years old, diagnosed with Leigh Syndrome due to a point mutation in the MT-ATP6 gene (respiratory chain V complex deficiency), presented with a lowered level of consciousness, ataxia and vomiting at 8 years old. Both with brain MRI with symmetrical hypersignal of the basal ganglia on T2/FLAIR.

Discussion: Mitochondrial diseases are the most common hereditary metabolic diseases, with an approximate prevalence of 1:5000 births, the presentation can start at any age group, can affect a single organ or be multisystemic, affecting organs that demand more energy, such as the brain, skeletal muscle, eyes and heart. The clinical presentation is varied even in mutations within the same complex of the respiratory chain. In our sample, we observed that patients with the NDUFAF5 and NDUFS1 mutations have mitochondrial complex 1 deficiency, and the clinic between them was not similar.

Final comments: The clinical presentation of mitochondrial diseases is greatly varied. In the face of clinical suspicion, one should proceed with genetic investigation and start with vitamin cocktails.

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

Publication History

Article published online:
18 September 2023