The Many Faces of Cobalamin (Vitamin B12) Deficiency

Bruce H R Wolffenbuttel; Hanneke J C M Wouters; M Rebecca Heiner-Fokkema; Melanie M van der Klauw

doi:10.1016/j.mayocpiqo.2019.03.002

The Many Faces of Cobalamin (Vitamin B₁₂) Deficiency

Mayo Clin Proc Innov Qual Outcomes. 2019 May 27;3(2):200-214. doi: 10.1016/j.mayocpiqo.2019.03.002. eCollection 2019 Jun.

Authors

Bruce H R Wolffenbuttel¹, Hanneke J C M Wouters^{1

2}, M Rebecca Heiner-Fokkema³, Melanie M van der Klauw¹

Affiliations

¹ Department of Endocrinology, University of Groningen, University Medical Center Groningen, Groningen, NL-9700 RB, The Netherlands.
² Department of Haematology, University of Groningen, University Medical Center Groningen, Groningen, NL-9700 RB, The Netherlands.
³ Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, NL-9700 RB, The Netherlands.

Abstract

Although cobalamin (vitamin B₁₂) deficiency was described over a century ago, it is still difficult to establish the correct diagnosis and prescribe the right treatment. Symptoms related to vitamin B₁₂ deficiency may be diverse and vary from neurologic to psychiatric. A number of individuals with vitamin B₁₂ deficiency may present with the classic megaloblastic anemia. In clinical practice, many cases of vitamin B₁₂ deficiency are overlooked or sometimes even misdiagnosed. In this review, we describe the heterogeneous disease spectrum of patients with vitamin B₁₂ deficiency in whom the diagnosis was either based on low serum B₁₂ levels, elevated biomarkers like methylmalonic acid and/or homocysteine, or the improvement of clinical symptoms after the institution of parenteral vitamin B₁₂ therapy. We discuss the possible clinical signs and symptoms of patients with B₁₂ deficiency and the various pitfalls of diagnosis and treatment.

Keywords: CoA, coenzyme A; IF, intrinsic factor; IM, intramuscularly; MMA, methylmalonic acid; holoTC, holotranscobalamin.

Publication types

Review