Inborn mitochondrial cytopathies

Although the overall prevalence of these inborn mitochondrial cytopathies remains unknown, the frequency of the A3243G mtDNA point mutation alone is estimated to be 1.6 in 10,000 in a Finnish population (Majamaa et al. 1998). Overall, clinically patent mitochondrial cytopathies could exist with a frequency of around 1 in 5,000 children (Haas et al. 2007). 

The presence of diverse comorbid factors that also impair mitochondrial function (such as inborn mitochondrial cytopathies, inborn (3-oxidation defects, viral infections, obesity-associated NASH, or pregnancy) may play an important role in the idios3tncratic occurrence of these drag-induced adverse effects. 

Mitochondrial cytopathies affect mitochondrial respiration, which may secondarily inhibit p-oxidation, as explained above. Mitochondrial cytopathies may therefore be revealed during the administration of drugs that have mitochondrial effects. Thus, the administration of valproate, which inhibits mitochondrial p-oxidation and pyruvate-supported respiration, may reveal a previously latent mitochondrial cytopathy (Chabrol et al. 1994 Lam et al. 1997 Krahenbiihl et al. 2000). For the same reasons, valproate administration can also reveal an inborn p-oxidation defect (Nj0lstad et al. 1997 Kottlors et al. 2001). 

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