{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,24]],"date-time":"2026-02-24T11:13:28Z","timestamp":1771931608078,"version":"3.50.1"},"reference-count":52,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,2,12]],"date-time":"2026-02-12T00:00:00Z","timestamp":1770854400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Med."],"abstract":"<jats:p>\n                    Coenzyme Q10, also known as CoQ10, CoQ, and ubiquinone is an essential component of the mitochondrial electron-transport chain and functions as an energy transfer molecule as well as a redox carrier and is a lipid-soluble antioxidant. Biallelic pathogenic variants in one of the 10 genes encoding proteins involved in its synthesis, establishes the diagnosis of primary CoQ10 deficiency.\n                    <jats:italic>COQ2<\/jats:italic>\n                    , or parahydroxybenzoate-polyprenyltransferase (EC 2.5.1.39), catalyzes one of the final reactions in the biosynthesis of CoQ, the prenylation of parahydroxybenzoate with an all-trans polyprenyl group.\n                    <jats:italic>COQ2<\/jats:italic>\n                    related CoQ10 deficiency can present with multiple system atrophy, cardiomyopathy and steroid resistant nephrotic syndrome (SRNS). Multiple papers have suggested CoQ supplement can treat SRNS. We report a 9-year-old girl presenting with steroid-resistant nephrotic syndrome, whose renal biopsy revealed focal segmental glomerulosclerosis. She showed only a partial response to combined therapy with tacrolimus, lisinopril, and losartan. Whole exome sequencing identified two compound heterozygous variants in the\n                    <jats:italic>COQ2<\/jats:italic>\n                    gene (NM_015697.7): a known pathogenic variant, c.683A&amp;gt;G, inherited from her father, and a novel splice-site variant, c.692+3A&amp;gt;G, inherited from her mother and currently classified as a variant of uncertain significance (VUS). Notably, previously reported patients carrying the c.683A&amp;gt;G variant typically present with early-onset, severe disease. In contrast, our patient\u2019s relatively late onset and isolated nephropathy suggests that the novel variant may be pathogenic but associated with a milder phenotype. Prompt genetic diagnosis enabled early initiation of high-dose CoQ10 supplementation (ubiquinone, 30\u202fmg\/kg\/day), which led to marked clinical improvement and may have prevented further renal function deterioration or the development of other systemic manifestations.\n                  <\/jats:p>","DOI":"10.3389\/fmed.2026.1682564","type":"journal-article","created":{"date-parts":[[2026,2,12]],"date-time":"2026-02-12T05:31:35Z","timestamp":1770874295000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Case Report: Pediatric nephrology\u2014expanding the genotypic spectrum of COQ2-related nephropathy with a novel splice site variant in CoQ10-responsive SRNS"],"prefix":"10.3389","volume":"13","author":[{"given":"Yu-Ren","family":"Huang","sequence":"first","affiliation":[{"name":"Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine and University Hospitals","place":["Cleveland, OH, United States"]},{"name":"Department of Urology, Case Western Reserve University School of Medicine and University Hospitals","place":["Cleveland, OH, United States"]},{"name":"School of Medicine, China Medical University College of Medicine","place":["Taichung City, Taiwan"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Abhijeet","family":"Pal","sequence":"additional","affiliation":[{"name":"Section of Nephrology, Department of Pediatrics, St. Christopher's Hospital for Children","place":["Philadelphia, PA, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Anne Chun-Hui","family":"Tsai","sequence":"additional","affiliation":[{"name":"School of Medicine, China Medical University College of Medicine","place":["Taichung City, Taiwan"]},{"name":"Section of Genetics, Department of Pediatrics, University of Illinois Chicago","place":["Chicago, IL, United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2026,2,12]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"519","DOI":"10.1042\/BJ20040261","article-title":"Isolation and functional expression of human COQ2, a gene encoding a polyprenyl transferase involved in the synthesis of CoQ","volume":"382","author":"Forsgren","year":"2004","journal-title":"Biochem J"},{"key":"ref2","doi-asserted-by":"publisher","first-page":"1073","DOI":"10.1016\/j.bbabio.2016.03.010","article-title":"Coenzyme Q biosynthesis and its role in the respiratory chain structure","volume":"1857","author":"Alc\u00e1zar-Fabra","year":"2016","journal-title":"Biochim Biophys Acta"},{"key":"ref3","doi-asserted-by":"publisher","first-page":"207","DOI":"10.1258\/000456303321610493","article-title":"Ubiquinone: cholesterol\u2019s reclusive cousin","volume":"40","author":"Hargreaves","year":"2003","journal-title":"Ann Clin 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