Abstract
Riboflavin and ubiquinone (Coenzyme Q(10), CoQ(10)) deficiencies are heterogeneous groups of autosomal recessive conditions affecting both children and adults. Riboflavin (vitamin B(2))-derived cofactors are essential for the function of numerous dehydrogenases. Genetic defects of the riboflavin transport have been detected in Brown-Vialetto-Van Laere and Fazio-Londe syndromes (C20orf54), and haploinsufficiency of GPR172B has been proposed in one patient to cause persistent riboflavin deficiency. Mutations in the electron tranferring fravoprotein genes (ETFA/ETFB) and its dehydrogenase (ETFDH) are causative for multiple acyl-CoA dehydrogenase deficiency. Mutations in ACAD9, encoding the acyl-CoA dehydrogenase 9 protein were recently reported in mitochondrial disease with respiratory chain complex I deficiency. All these conditions may respond to riboflavin therapy. CoQ(10) is a lipid-soluble component of the cell membranes, where it functions as a mobile electron and proton carrier, but also participates in other cellular processes as a potent antioxidant, and by influencing pyrimidine metabolism. The increasing number of molecular defects in enzymes of the CoQ(10) biosynthetic pathways (PDSS1, PDSS2, COQ2, COQ6, COQ9, CABC1/ADCK3) underlies the importance of these conditions. The clinical heterogeneity may reflect blocks at different levels in the complex biosynthetic pathway. Despite the identification of several primary CoQ(10) deficiency genes, the number of reported patients is still low, and no true genotype-phenotype correlations are known which makes the genetic diagnosis still difficult. Additionally to primary CoQ(10) deficiencies, where the mutation impairs a protein directly involved in CoQ(10) biosynthesis, we can differentiate secondary deficiencies. CoQ(10) supplementation may be beneficial in both primary and secondary deficiencies and therefore the early recognition of these diseases is of utmost importance.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.