COQ2 nephropathy: A newly described inherited mitochondriopathy with primary renal involvement

Francesca Diomedi-Camassei, Silvia Di Giandomenico, Filippo M. Santorelli, Gianluca Caridi, Fiorella Piemonte, Giovanni Montini, Gian Marco Ghiggeri, Luisa Murer, Laura Barisoni, Anna Pastore, Andrea Onetti Muda, Maria Luisa Valente, Enrico Bertini, Francesco Emma

Research output: Contribution to journalArticlepeer-review

Abstract

Primary coenzyme Q10 (CoQ10) deficiency includes a group of rare autosomal recessive disorders primarily characterized by neurological and muscular symptoms. Rarely, glomerular involvement has been reported. The COQ2 gene encodes the para-hydroxybenzoate-polyprenyl-transferase enzyme of the CoQ10 synthesis pathway. We identified two patients with early-onset glomerular lesions that harbored mutations in the COQ2 gene. The first patient presented with steroid-resistant nephrotic syndrome at the age of 18 months as a result of collapsing glomerulopathy, with no extrarenal symptoms. The second patient presented at five days of life with oliguria, had severe extracapillary proliferation on renal biopsy, rapidly developed end-stage renal disease, and died at the age of 6 months after a course complicated by progressive epileptic encephalopathy. Ultrastructural examination of renal specimens from these cases, as well as from two previously reported patients, showed an increased number of dysmorphic mitochondria in glomerular cells. Biochemical analyses demonstrated decreased activities of respiratory chain complexes [II+III] and decreased CoQ10 concentrations in skeletal muscle and renal cortex. In conclusion, we suggest that inherited COQ2 mutations cause a primary glomerular disease with renal lesions that vary in severity and are not necessarily associated with neurological signs. COQ2 nephropathy should be suspected when electron microscopy shows an increased number of abnormal mitochondria in podocytes and other glomerular cells.

Original languageEnglish
Pages (from-to)2773-2780
Number of pages8
JournalJournal of the American Society of Nephrology
Volume18
Issue number10
DOIs
Publication statusPublished - Oct 2007

ASJC Scopus subject areas

  • Nephrology

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