Abstract:
Mitochondrial disorders are frequently encountered
inherited diseases characterized by unexplained
multisystem involvement with a chronic, intermittent, or
progressive nature. The objective of this paper is to describe
the profile of patients with mitochondrial disorders in South
Africa. Patients with possible mitochondrial disorders were
accessed over 10 years. Analyses for respiratory chain and
pyruvate dehydrogenase complex enzymes were performed
on muscle. A diagnosis of a mitochondrial disorder was
accepted only if an enzyme activity was deficient. Sixtythree
patients were diagnosed with a mitochondrial disorder,
including 40 African, 20 Caucasian, one mixed ancestry, and
two Indian patients. The most important findings were the
difference between African patients and other ethnicities:
respiratory chain enzyme complexes CI+III or CII+III
deficiencies were found in 52.5% of African patients, being
of statistical significance (p value=0.0061). They also
presented predominantly with myopathy (p value=
0.0018); the male:female ratio was 1:1.2. Twenty-five
(62.5%) African patients presented with varying degrees
of a myopathy accompanied by a myopathic face, high
palate, and scoliosis. Fourteen of these 25 also had ptosis
and/or progressive external ophthalmoplegia. No patients of
other ethnicities presented with this specific myopathic
phenotype. Caucasian patients (16/20) presented predominantly
with central nervous system involvement. Of the
South African pediatric neurology patients, Africans are
more likely to present with myopathy and CII+III deficiency,
and Caucasian patients are more likely to present with
encephalopathy or encephalomyopathy
