Distal phalangeal erythema in an infant with biallelic PDSS1 mutations: Expanding the phenotype of primary Coenzyme Q10 deficiency

Efficacy and Safety of Coenzyme Q10 Supplementation in Neonates, Infants and Children: An Overview

To date, there have been no review articles specifically relating to the general efficacy and safety of coenzyme Q10 (CoQ10) supplementation in younger subjects. In this article, we therefore reviewed the efficacy and safety of CoQ10 supplementation in neonates (less than 1 month of age), infants (up to 1 year of age) and children (up to 12 years of age). As there is no rationale for the supplementation of CoQ10 in normal younger subjects (as there is in otherwise healthy older subjects), all of the articles in the medical literature reviewed in the present article therefore refer to the supplementation of CoQ10 in younger subjects with a variety of clinical disorders; these include primary CoQ10 deficiency, acyl CoA dehydrogenase deficiency, Duchenne muscular dystrophy, migraine, Down syndrome, ADHD, idiopathic cardiomyopathy and Friedreich's ataxia.

The role of CoQ10 in embryonic development

Coenzyme Q10 (CoQ10) is a natural component widely present in the inner membrane of mitochondria. CoQ10 functions as a key cofactor for adenosine triphosphate (ATP) production and exhibits antioxidant properties in vivo. Mitochondria, as the energy supply center of cells, play a crucial role in germ cell maturation and embryonic development, a complicated process of cell division and cellular differentiation that transforms from a single cell (zygote) to a multicellular organism (fetus). Here, we discuss the effects of CoQ10 on oocyte maturation and the important role of CoQ10 in the growth of various organs during different stages of fetal development. These allowed us to gain a deeper understanding of the pathophysiology of embryonic development and the potential role of CoQ10 in improving fertility quality. They also provide a reference for further developing its application in clinical treatments.

Primary Coenzyme Q10 Deficiency: An Update

Coenzyme Q10 (CoQ10) has a number of vital functions in all cells, both mitochondrial and extra-mitochondrial. In addition to its key role in mitochondrial oxidative phosphorylation, CoQ10 serves as a lipid soluble antioxidant and plays an important role in fatty acid beta-oxidation and pyrimidine and lysosomal metabolism, as well as directly mediating the expression of a number of genes, including those involved in inflammation. Due to the multiplicity of roles in cell function, it is not surprising that a deficiency in CoQ10 has been implicated in the pathogenesis of a wide range of disorders. CoQ10 deficiency is broadly divided into primary and secondary types. Primary CoQ10 deficiency results from mutations in genes involved in the CoQ10 biosynthetic pathway. In man, at least 10 genes are required for the biosynthesis of functional CoQ10, a mutation in any one of which can result in a deficit in CoQ10 status. Patients may respond well to oral CoQ10 supplementation, although the condition must be recognised sufficiently early, before irreversible tissue damage has occurred. In this article, we have reviewed clinical studies (up to March 2023) relating to the identification of these deficiencies, and the therapeutic outcomes of CoQ10 supplementation; we have attempted to resolve the disparities between previous review articles regarding the usefulness or otherwise of CoQ10 supplementation in these disorders. In addition, we have highlighted several of the potential problems relating to CoQ10 supplementation in primary CoQ10 deficiency, as well as identifying unresolved issues relating to these disorders that require further research.

Neuroimaging in Primary Coenzyme-Q10-Deficiency Disorders

Coenzyme Q10 (CoQ10) is an endogenously synthesized lipid molecule. It is best known for its role as a cofactor within the mitochondrial respiratory chain where it functions in electron transfer and ATP synthesis. However, there are many other cellular pathways that also depend on the CoQ10 supply (redox homeostasis, ferroptosis and sulfide oxidation). The CoQ10 biosynthesis pathway consists of several enzymes, which are encoded by the nuclear DNA. The majority of these enzymes are responsible for modifications of the CoQ-head group (benzoquinone ring). Only three enzymes (PDSS1, PDSS2 and COQ2) are required for assembly and attachment of the polyisoprenoid side chain. The head-modifying enzymes may assemble into resolvable domains, representing COQ complexes. During the last two decades, numerous inborn errors in CoQ10 biosynthesis enzymes have been identified. Thus far, 11 disease genes are known (PDSS1, PDSS2, COQ2, COQ4, COQ5, COQ6, COQ7, COQ8A, COQ8B, COQ9 and HPDL). Disease onset is highly variable and ranges from the neonatal period to late adulthood. CoQ10 deficiency exerts detrimental effects on the nervous system. Potential consequences are neuronal death, neuroinflammation and cerebral gliosis. Clinical features include encephalopathy, regression, movement disorders, epilepsy and intellectual disability. Brain magnetic resonance imaging (MRI) is the most important tool for diagnostic evaluation of neurological damage in individuals with CoQ10 deficiency. However, due to the rarity of the different gene defects, information on disease manifestations within the central nervous system is scarce. This review aims to provide an overview of brain MRI patterns observed in primary CoQ10 biosynthesis disorders and to highlight disease-specific findings.