Doping May Be Responsible forDe Novo Mitochondrial Disorder

In a recent article by Jackson et al, a 9 years-old girl with microcephaly, developmental delay, intellectual disability, and ataxia was presented.1 Already in early infancy the patient developed sucking weakness, motor development was delayed (sitting independently at age 15m, walking independently at age 22m), and she showed a tendency to freeze easily.1 The patient had gallstones at age 4m. From age 7m she developed ataxia, microcephaly, short stature, with a delay in motor development, and serum and CSF lactate were repeatedly elevated. Biochemical investigations of primary fibroblast cultures and muscle homogenate showed severe reduction of complex-V of the respiratory chain with a residual activity of 25% in muscle and 28% in fibroblasts.1 Ultrastructurally, mitochondria were distorted with aberrant cristae formation. Western blot analysis of mitochondrial proteins showed reduced complex-V amount and impaired complex-V assembly.1 Sequencing of the mtDNA-located genes MT-ATP6/8 revealed the heteroplasmic insertion C at position 8611 (m.8611_8612insC).