Primary coenzyme Q10 deficiency and the brain

Our findings in 19 new patients with cerebellar ataxia establish the existence of an ataxic syndrome due to primary CoQ(10) deficiency and responsive to CoQ(10) therapy. As all patients presented cerebellar ataxia and cerebellar atrophy, this suggests a selective vulnerability of the cerebellum to CoQ(10) deficiency. We investigated the regional distribution of coenzyme Q(10) in the brain of adult rats and in the brain of one human subject. We also evaluated the levels of coenzyme Q(9) (CoQ(9)) and CoQ(10) in different brain regions and in visceral tissues of rats before and after oral administration of CoQ(10). Our results show that in rats, amongst the seven brain regions studied, cerebellum contains the lowest level of CoQ. However, the relative proportion of CoQ(10) was the same (about 30% of total CoQ) in all regions studied. The level of CoQ(10) is much higher in brain than in blood or visceral tissue, such as liver, heart, or kidney. Daily oral administration of CoQ(10) led to substantial increases of CoQ(10) concentrations only in blood and liver. Of the four regions of one human brain studied, cerebellum again had the lowest CoQ(10)y concentration.