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Coenzym Q10 defects - COQ2, COQ9, PDSS1, PDSS2, CABC1/ADCK3, APTX, ETFDH, EFTA, EFTB

Clinical Features

Coenzyme Q10 Deficiency is an autosomal recessive inherited disease that can occur in association with at least five different clinical phenotypes:

• Encephalomyopathy with exercise intolerance, mitochondrial myopathy, myoglobinuria, epilepsy and ataxia (Ogasahara et al., 1989; Sobreira et al., 1997)
• Multisystemic infantile encephalomyopathy, cardiomyopathy, ataxia, optical neuropathy, deafness and nephrosis (Rotig et al., 2000)
• Cerebellar ataxia (Lamperti et al., 2003)
• Leigh Syndrome with dwarfism, ataxia and deafness (Maldergem et al., 2002)
• Isolated myopathy (Horváth et al., 2006)

Genetic Information

The genetic background of Coenzyme Q defects is very heterogeneous and the number of identified causal gene defects is growing quickly. Recently, a number of pathogenic mutations in various Coenzyme Q biosynthesis genes (COQ2, COQ9, PDSS1, PDSS2, CABC1) have been described for patients with infantile or early childhood encephalomyopathy. This group of Coenzyme Q deficiencies are called primary Coenzyme Q defects. Secondary Coenzyme Q deficiency is caused by gene defects that influence Coenzyme Q biosynthesis.

Pathogenic mutations in the APTX gene (aprataxin) in patients with Ataxia with Oculomotor Apraxia Type 1 or in the ETFDH gene (Electron Transfer Flavoprotein Dehydrogenase) in patients with isolated myopathy can also lead to muscular Coenzyme Q10 deficiency. These patients show noticeable clinical improvement while undergoing Coenzyme Q10 therapy.

Prevalence

Unknown

Diagnostic