title: Atypical glomerulopathy associated with the cblE inborn error of vitamin B₁₂ metabolism.
abstract: BACKGROUND
  The cblE disorder is an inherited disorder of vitamin B12 metabolism that results in elevated levels of homocysteine and decreased methionine in body fluids. Renal complications have been reported in patients with cblC disease, but not in those with cblE disease. The renal complications of cblC disease include thrombotic microangiopathy (TMA), neonatal hemolytic uremic syndrome, chronic renal failure, tubulointerstitial nephritis and proximal renal tubular acidosis. Previously, we reported a patient with cblC disease who had an atypical glomerulopathy that manifested with proteinuria and progressive renal insufficiency.
  
  
  METHODS
  Studies were done on cultured fibroblasts. Renal biopsy tissue was examined by light and electron microscopy. There was decreased incorporation of labeled methyltetrahydrofolate and decreased synthesis of methylcobalamin. Complementation analysis placed the patient into the cblE complementation group. The findings from the histological and ultrastructural studies of renal biopsy were similar, but not identical, to those of idiopathic membranoproliferative glomerulonephritis (MPGN) and overlapped with those of TMA.
  
  
  CONCLUSIONS
  We describe a patient with cblE disease who had an atypical glomerulopathy similar to MPGN. Additional findings included migraine headaches, hypothyroidism and livedo reticularis.
authors.affiliation: Department of Pediatrics, Columbia Medical Center, 630 W 168th St, New York, NY 10032, USA.
authors.forename: Erin A
authors.initials: EA
authors.lastname: Paul
authors.forename: Marta
authors.initials: M
authors.lastname: Guttenberg
authors.forename: Paige
authors.initials: P
authors.lastname: Kaplan
authors.forename: David
authors.initials: D
authors.lastname: Watkins
authors.forename: David S
authors.initials: DS
authors.lastname: Rosenblatt
authors.forename: James R
authors.initials: JR
authors.lastname: Treat
authors.forename: Bernard S
authors.initials: BS
authors.lastname: Kaplan
mesh_terms: D000749:Anemia, Megaloblastic / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics; D001706:Biopsy; D002478:Cells, Cultured; D018450:Disease Progression; D005260:Female; D005347:Fibroblasts / Q000378:metabolism* / Q000473:pathology; D005816:Genetic Complementation Test; D020022:Genetic Predisposition to Disease; D015432:Glomerulonephritis, Membranoproliferative / Q000175:diagnosis / Q000209:etiology*; D006712:Homocystinuria / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics; D006801:Humans; D006879:Hydroxocobalamin / Q000627:therapeutic use; D007037:Hypothyroidism / Q000209:etiology; D007668:Kidney / Q000378:metabolism* / Q000473:pathology; D054068:Livedo Reticularis / Q000209:etiology; D008881:Migraine Disorders / Q000209:etiology; D010641:Phenotype; D011237:Predictive Value of Tests; D051436:Renal Insufficiency, Chronic / Q000209:etiology; D013997:Time Factors; D014805:Vitamin B 12 / Q000378:metabolism*; D014803:Vitamin B Complex / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D014803:Vitamin B Complex; D014805:Vitamin B 12; D006879:Hydroxocobalamin