Coenzyme Q₁₀ (CoQ₁₀) deficiency is a rare disease characterized by a decreased accumulation of CoQ₁₀ in cell membranes. Considering that CoQ₁₀ synthesis and most of its functions are carried out in mitochondria, CoQ₁₀ deficiency cases are usually considered a mitochondrial disease. A relevant feature of CoQ₁₀ deficiency is that it is the only mitochondrial disease with a successful therapy available, the CoQ₁₀ supplementation. Defects in components of the synthesis machinery caused by mutations in COQ genes generate the primary deficiency of CoQ₁₀. Mutations in genes that are not directly related to the synthesis machinery cause secondary deficiency. Cases of CoQ₁₀ deficiency without genetic origin are also considered a secondary deficiency. Both types of deficiency can lead to similar clinical manifestations, but the knowledge about primary deficiency is deeper than secondary. However, secondary deficiency cases may be underestimated since many of their clinical manifestations are shared with other pathologies. This review shows the current state of secondary CoQ₁₀ deficiency, which could be even more relevant than primary deficiency for clinical activity. The analysis covers the fundamental features of CoQ₁₀ deficiency, which are necessary to understand the biological and clinical differences between primary and secondary CoQ₁₀ deficiencies. Further, a more in-depth analysis of CoQ₁₀ secondary deficiency was undertaken to consider its origins, introduce a new way of classification, and include aging as a form of secondary deficiency.

中文翻译：

---

继发性辅酶Q10缺乏，疾病和衰老中的生物能量失衡

辅酶 Q ₁₀ (CoQ ₁₀ ) 缺乏症是一种罕见的疾病，其特征是细胞膜中辅酶 Q _{10 的}积累减少。考虑到辅酶Q _{10 的}合成及其大部分功能是在线粒体中进行的，辅酶Q ₁₀缺乏病例通常被认为是一种线粒体疾病。辅酶Q ₁₀缺乏症的一个相关特征是它是唯一一种可以成功治疗的线粒体疾病，即辅酶Q ₁₀补充剂。由COQ基因突变引起的合成机制组件缺陷导致CoQ ₁₀的主要缺陷. 与合成机制不直接相关的基因突变会导致继发性缺陷。没有遗传来源的 CoQ ₁₀缺乏症也被认为是继发性缺乏症。两种类型的缺乏都会导致相似的临床表现，但对原发性缺乏的了解比继发性更深。然而，继发性缺陷病例可能被低估，因为它们的许多临床表现与其他病理相同。这篇综述显示了继发性 CoQ ₁₀缺乏症的现状，这可能比临床活动的原发性缺乏症更相关。分析涵盖了 CoQ ₁₀的基本特征缺乏，这是了解原发性和继发性 CoQ ₁₀缺乏症之间的生物学和临床差异所必需的。此外，对辅酶Q ₁₀继发性缺乏症进行了更深入的分析，以考虑其起源，引入一种新的分类方式，并将老化作为继发性缺乏症的一种形式。