Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Case Reports
. 2020 Apr-Jun;15(2):140-144.
doi: 10.4103/jpn.JPN_132_19. Epub 2020 Jun 27.

Delayed Diagnosis of Cobalamin E Defect in an Adolescent Patient

Merve Koç Yekedüz  1 , Elif Unal Ince  2 , Talia İleri  2 , Mehmet Ertem  2 , Fatma Tuba Eminoğlu  1
Affiliations
Case Reports

Delayed Diagnosis of Cobalamin E Defect in an Adolescent Patient

Merve Koç Yekedüz et al. J Pediatr Neurosci. 2020 Apr-Jun.

Abstract

Cobalamin and its metabolites play a critical role in deoxyribonucleic acid synthesis. Disorders of cobalamin metabolism are rare and related with neurological and hematological problems. We report an adolescent patient with cobalamin E (CblE) defect presenting with megaloblastic anemia, mental retardation, cerebral atrophy, cortical visual impairment, white matter changes on brain magnetic resonance imaging, and hyperhomocysteinemia. Homozygous mutation at the c.245C>T in exon 3 of the MTRR gene was identified, which had been found to be related to CblE defect. He was treated with betaine, folic acid, vitamin B6, riboflavin, hydroxycobalamin (OH-B12), and carnitine. During treatment, homocysteine levels decreased over time.

Keywords: Cobalamin E defect; errors of vitamin B12 metabolism; hyperhomocysteinemia; remethylation defects.

PubMed Disclaimer

Conflict of interest statement

There are no conflicts of interest.

Figures

Figure 1
Figure 1
Molecular pathway of CblE
Figure 2
Figure 2
Differential diagnosis of CblE gene defect
See this image and copyright information in PMC

References

    1. Kandula T, Peters H, Fahey M. Cobalamin E defect, a rare inborn error of vitamin B12 metabolism: value of early diagnosis and treatment. J Clin Neurosci. 2014;21:1815–7. - PubMed
    1. Huemer M, Bürer C, Ješina P, Kožich V, Landolt MA, Suormala T, et al. Clinical onset and course, response to treatment and outcome in 24 patients with the CblE or CblG remethylation defect complemented by genetic and in vitro enzyme study data. J Inherit Metab Dis. 2015;38:957–67. - PubMed
    1. Huemer M, Diodato D, Schwahn B, Schiff M, Bandeira A, Benoist JF, et al. Guidelines for diagnosis and management of the cobalamin-related remethylation disorders CblC, CblD, CblE, CblF, CblG, CblJ and MTHFR deficiency. J Inherit Metab Dis. 2017;40:21–48. - PMC - PubMed
    1. Watkins D, Rosenblatt DS. Inborn errors of cobalamin absorption and metabolism. Am J Med Genet C Semin Med Genet. 2011;157C:33–44. - PubMed
    1. Hallam LJ, Sawyer M, Clark AC, Van der Weyden MB. Vitamin B12-responsive neonatal megaloblastic anemia and homocystinuria with associated reduced methionine synthase activity. Blood. 1987;69:1128–33. - PubMed

Publication types