New data supporting that early diagnosis and treatment are possible and necessary in intracellular cobalamin depletion: the case of transcobalamin II deficiency.

OBJECTIVES: Transcobalamin II (TC) promotes the cellular uptake of cobalamin (Cbl) through receptor-mediated endocytosis of the TC-cbl complex in peripheral tissues. TC deficiency is a rare disorder that causes intracellular Cbl depletion. It presents in early infancy with a failure to thrive, diarrhea, anemia, agammaglobulinemia, and pancytopenia. Data from five TC-deficient patients including clinical, biochemical, and molecular findings, as well as long-term outcomes, were collected. CASE PRESENTATION: Mutation analysis revealed one unreported pathogenic variant in the TCN2 gene. One patient had exocrine pancreatic insufficiency. We conducted a retrospective analysis of C3 and C3/C2 from dried blood samples, as this is implemented for newborn screening (NBS). We detected a marked increase in the C3/C2 ratio in two samples. Treatment was based on parenteral Cbl. Three patients treated before six months of age had an initial favorable outcome, whereas the two treated later or inadequately had neurological impairment. CONCLUSIONS: This is the first report of Argentinean patients with TC deficiency that detected a new variant in TCN2. NBS may be a tool for the early detection of TC deficiency. This data emphasizes that TC deficiency is a severe disorder that requires early detection and long-term, aggressive therapy. Accurate diagnosis is imperative, because early detection and treatment can be life-saving.

Macro-B12 and Unexpectedly High Levels of Plasma B12: A Critical Review.

A low total plasma vitamin B12 supports a clinical suspicion of B12 deficiency, while the interpretation of an unexpectedly normal/high level is marred by controversies. Here, we critically review current knowledge on B12 in blood plasma, including the presence of the so-called "macro-B12". The latter form is most often defined as the fraction of B12 that can be removed by precipitation with polyethylene glycol (PEG), a nonspecific procedure that also removes protein polymers and antibody-bound analytes. Plasma B12 includes B12 attached to transcobalamin and haptocorrin, and an increased concentration of one or both proteins almost always causes an elevation of B12. The total plasma B12 is measured by automated competitive binding assays, often incorrectly referred to as immunoassays, since the binding protein is intrinsic factor and not an antibody. An unexpectedly high level of B12 may be further explored using immunological measurements of haptocorrin and transcobalamin (optionally combined with e.g., size-exclusion chromatography). Nonspecific methods, such as PEG precipitation, are likely to give misleading results and cannot be recommended. Currently, the need for evaluation of a high B12 of unknown etiology is limited since other tests (such as measurements of methylmalonic acid) may better guide the diagnosis of B12 deficiency.

Severe Hemolytic Anemia: Atypical Presentation of Cobalamin Deficiency.

Two severe cases of hemolytic anemia are described in different pediatric age groups, both linked to severe cobalamin deficiency from distinct causes. The first case refers to an exclusively breastfed infant with vitamin deficit secondary to maternal impaired absorption. Apart from the neurological deficits present at diagnosis, he also presented with infantile epileptic spasms syndrome a few months after treatment while having normal cobalamin serum levels. The second case refers to an adolescent with long-term inadequate intake. The occurrence of severe hemolytic anemia in cobalamin deficiency is exceptionally rare.

Nitrous oxide induced subacute combined degeneration of the spine cord: A case report.

RATIONALE: In recent years, recreational use of inhaled nitrous oxide (N2O) is on the increase among young people, accompanied by a corresponding rise in reports about its toxicity. Subacute combined degeneration of the spine cord (SCD) is the typical clinical picture of the nervous system disorder caused by N2O intoxication, as a result of metabolic disturbance of vitamin B12. PATIENT CONCERNS, DIAGNOSES, INTERVENTIONS AND OUTCOMES: We report a 28-year-old female of SCD due to prolonged use of N2O, presented with paresthesia and unsteady in walking progressing within 1 month. Symptoms gradually improved with the treatment of intramuscular injections of hydroxocobalamin combined with N2O abstinence, and the patient recovered completely with normal neurological examination after 4 months of follow-up. LESSONS: Clinicians should be aware of the clinical features and pathogenesis of SCD caused by N2O intoxication in order to lead effective treatment as soon as possible. Recreational N2O use should always be considered as an etiology when dealing with patients presented with myelopathy and/or neuropathy suspected of vitamin B12 deficiency.

Vitamin B12 is associated negatively with anemia in older Chinese adults with a low dietary diversity level: evidence from the Healthy Ageing and Biomarkers Cohort Study (HABCS).

OBJECTIVE: The associations between plasma vitamin B12 level and anemia under different dietary patterns in elderly Chinese people are poorly understood. We aimed to examine the associations between plasma vitamin B12 levels and anemia under different dietary patterns in adults aged 65 years and older in nine longevity areas in China. METHODS: A total of 2405 older adults completed a food frequency questionnaire at the same time as a face-to-face interview. The dietary diversity score (DDS) was assessed based on the food frequency questionnaire, with the low DDS group referring to participants with a DDS score ≤ 4 points. Vitamin B12 levels were divided into two groups of high (>295 pg/mL) and low (≤ 295 pg/mL) with the median used as the cut-off point. Sub-analyses were also performed on older adults divided into tertiles of vitamin B12 levels: low (< 277 pg/mL), medium (277-375 pg/mL) and high (> 375 pg/mL) to study the association of these levels with anemia. RESULTS: Six hundred ninety-five (28.89%) of these people were diagnosed with anemia and had a mean age of 89.3 years. Higher vitamin B12 levels were associated with a decreased risk of anemia (multi-adjusted OR, 0.59, [95% CI, 0.45 ~ 0.77] P < 0.001) in older adults with a low DDS, whereas no significant association between vitamin B12 levels and anemia was found in older adults with a high DDS in a full-model after adjustment for various confounding factors (multi-adjusted OR, 0.88, [95% CI, 0.65 ~ 1.19], P = 0.41). CONCLUSION: The relationship between vitamin B12 levels and the prevalence of anemia was significant only when the level of dietary diversity in the older adults was relatively low. The dietary structure of the population should be taken into consideration in combination in order to effectively improve anemia status by supplementing vitamin B12.

Not a Laughing Matter: When Nitrous Oxide Causes Functional Vitamin B12 Deficiency.

Subacute combined degeneration (SCD) is an acquired neurologic complication from prolonged vitamin B12 deficiency. As a result of dorsal and lateral spinal cord column degeneration, patients present with a range of neurological symptoms, including paresthesias, ataxia, and muscle weakness. Without prompt treatment, irreversible nerve damage occurs. Here we present a young man who developed progressive ascending paresthesias and lower extremity weakness after escalated nitrous oxide use. This case highlights the importance of considering SCD from nitrous oxide toxicity when patients present with progressive ataxia, paresthesia, and lower extremity weakness.

A new perspective on vitamin B12 deficiency in rheumatology: a case-based review.

Vitamin B12 (cobalamin) deficiency is common in patients with rheumatic diseases. Pernicious anemia is a well-known cause, but recent reports suggest that autoimmune-derived deficiency may not be limited to this cause alone. Symptoms of low vitamin B12 concentration are often deceptive, mimicking and overlapping with symptoms of other conditions. Neuropsychiatric manifestations, anemia, and fatigue are frequently attributed to a rheumatic disease without further evaluation. In this study, we present three cases of patients with neuropathic pain, depression, fatigue, and muscle weakness, initially attributed to a rheumatic disease, which almost completely resolved after implementing vitamin B12 supplementation. Furthermore, we provide an overview of current scientific reports regarding the potential use of cobalamin in rheumatology. Treatment of pain and neuropathy, often very challenging in long-lasting rheumatic diseases, can be more effective after a course of vitamin B12, even when no apparent deficiency is detected in laboratory tests. Considering recent research demonstrating vitamin B12's nerve-protecting properties, we recommend that physicians should assess vitamin B12 levels early in the diagnostic process of rheumatic diseases. In specific cases, physicians should consider cobalamin supplementation regardless of vitamin B12 serum concentration.

Evaluation of vitamin B12 values at time of diagnosis in 0- to 36-month-old children with food allergies.

OBJECTIVES: The relationship between food allergies and vitamin B12 deficiency in young children remains unclear despite extensive studies on the nutritional status of affected children. The aim of this study was to compare vitamin B12 levels in children with recently diagnosed food allergies and healthy children ages 0 to 36 mo. METHODS: A retrospective study at Baskent University Hospital analyzed 773 patients ages 0 to 36 mo. Participants were divided into two groups: food allergy and healthy. Vitamin B12 deficiency (<300 ng/mL) was assessed using χ2 tests and regression analyses. RESULTS: The sample comprised 773 children ages 0 to 36 mo, with a mean age of 16 ± 9 mo (range: 1-36). Among the participants, 399 (52%) were healthy children, whereas 374 (48%) had food allergies. The prevalence of vitamin B12 deficiency was higher in children with food allergies (38%) than in healthy children (21%; P < 0.001). According to both univariate and multivariate regression analyses, formula feeding showed a negative association with vitamin B12 deficiency (ß = -0.54; 95% confidence interval [CI], 0.35-0.97; P = 0.038). On the other hand, having allergic diseases (ß = 0.69; 95% CI, 0.30-0.83; P = 0.040) and breastfeeding for <6 mo (ß = 1.35; 95% CI, 1.41-10.50-0.50; P = 0.009) exhibited a positive association with vitamin B12 deficiency. CONCLUSION: Food-allergic children ages 0 to 36 mo were at higher risk for vitamin B12 deficiency. Formula feeding had a protective effect, whereas allergic diseases and breastfeeding for <6 mo were risk factors. Further investigation is needed to understand the underlying mechanisms. Monitoring B12 levels and interventions are crucial for the nutritional well-being of food-allergic children.

Preliminary evaluation of the diagnostic performance of Roche Elecsys® active vitamin B12 versus total vitamin B12 for vitamin B12 deficiency screening.

INTRODUCTION: The prevalence of vitamin B12 deficiency is high in at-risk populations with sometimes irreversible consequences. Beside total B12 (TVB12), active B12 (AVB12) is a promising first-line marker. Only Abbott AVB12 assays were largely evaluated and generally demonstrated benefit in clinical practice. More recently developed Roche AVB12 still requires some investigations. OBJECTIVES: Our study aimed to evaluate the Roche Elecsys® AVB12 immunoassay performance versus Roche Elecsys® TVB12 competition assay. DESIGN: and Methods: We included 175 patients at Rouen University Hospital who had a TVB12 value <300 pmol/L. We evaluated performance of AVB12 by comparing the results with TVB12 and MMA values in case of disagreement. RESULTS: Positive correlation was found between the AVB12 and TVB12. We found a disagreement between TVB12 and AVB12 in 18.8% of cases. Among 33 cases of disagreement, 76% had normal AVB12 but low TVB12, whereas 24% had low AVB12 and normal TVB12. Thirty-one MMA determinations were performed: 71% showed agreement between MMA and AVB12, versus 29% between MMA and TVB12. TVB12 reported a sensitivity (Se) at 66.7%, specificity (Sp) at 20%, positive predictive value (PPV) at 16.7% and negative predictive value (NPV) at 71.4% for the prediction of MMA elevation. We determined an optimized cut-off value of 45.5 pmol/L for AVB12, which reported a Se 66.7%, Sp 60%, PPV 30.7%, and NPV 88.9%. CONCLUSIONS: Our results provide preliminary evidence that Roche AVB12 may offer better discrimination than Roche TVB12 in the diagnosis of vitamin B12 deficiency. Further more detailed evaluation is warranted.

Evaluation of Neurodevelopmental Screening Test Scores in Children with Vitamin B12 Deficiency.

INTRODUCTION: Vitamin B12 deficiency can lead to hematological findings, neurological symptoms, and neurodevelopmental delay. The aim of this study was to investigate the impact of vitamin B12 deficiency on the neurodevelopment of children. MATERIALS AND METHODS: This study included 89 children aged between 6 and 24 months without any complaints; 44 of these were evaluated in the study group (serum vitamin B12 <300 pg/mL) and 45 in the control group (serum vitamin B12 ≥300 pg/mL). Denver Developmental Screening Test II (DDST-II) and the Social Communication Area Screening Test (SCAST) were evaluated in each participant. RESULTS: The mean vitamin B12 level in the study group was 206.11 ± 9.1 pg/mL, and in the control group, it was 540.65 ± 24.1 pg/mL. When DDST-II results were analyzed, the rate of getting suspicious and abnormal results in the study group was significantly higher compared with the control group (p = 0.001). The rate of the "risky" SCAST results of the cases was found to be statistically significantly higher in the study group than in the control group (p = 0.003). Vitamin B12 values of patients with suspicious or abnormal DDST-II results and with risky SCAST results were found to be statistically significantly lower than those with normal neurodevelopmental screening tests results (p = 0.001 and p = 0.001, respectively). CONCLUSION: Vitamin B12 deficiency can lead to neurodevelopmental delay in children, even in the absence of neurological and hematological symptoms or complaints, which highlights the importance of early detection and intervention of vitamin B12 deficiency.

A case of functional vitamin B12 deficiency after recreational nitrous oxide use.

The recreational use of nitrous oxide as laughing gas becomes a real public health issue among adolescents and young adults. Chronic use is deleterious and can lead to severe neurological disorders. Nitrous oxide inactivates vitamin B12, and the functional defect of vitamin B12 plays a major role in the pathogenesis of nitrous oxide-related neurological disorders. Here we report the case of a 22-year-old woman who came to the hospital after an unexplained loss of consciousness. She exhibited typical features of vitamin B12 or folate deficiency such as macrocytic anemia and hypersegmented neutrophils. However, serum concentrations of folate and vitamin B12 were normal. In contrast, circulating concentrations of total homocysteine and methylmalonic acid were significantly increased. These results clearly indicated a defect in vitamin B12 functions. The reason for this defect was clarified when she revealed that she had been consuming nitrous oxide recreationally for over a year. The present case points out the challenges in diagnosing vitamin B12 deficiency in the context of nitrous oxide abuse due to normal concentrations of total serum vitamin B12 in a significant proportion of cases. The medical community should be aware of how difficult it can be to interpret B12 status in this specific population.

Coexistence and clinical implications of anemia and depression in the elderly population. / Wspólwystepowanie i implikacje kliniczne anemii i depresji u osób w podeszlym wieku.

Anemia and depression are common in the elderly and they are important medical, social and economic problems for the world. Both disorders are associated with a lower quality of life, multimorbidity and a higher risk of death. The connections between anemia and depression have been reported, but the mechanism and clinical consequences of their co-existence are not fully understood. Several links can be found between anemia and depression in the elderly: common etiological factors, low socioeconomic status of patients, poor education and less physical activity. Both conditions are associated with the occurrence of the same pathological changes: age-related (especially with the presence of inflammation, oxidative stress, degenerative changes in organs and tissues), nutritional deficiencies (iron, vitamin B12, folic acid) and hormonal disorders (especially thyroid gland disorders, sex hormone deficiencies). Anemia and depression are not sufficiently diagnosed in the elderly and, as a result, are often left untreated. The diagnosis and treatments of these conditions in the elderly differ from those in other age groups. The study provides an overview of the literature regarding the co-existence of anemia and depression in elderly patients and clinical recommendations.

Subacute combined degeneration of the spinal cord in a patient with nitrous oxide use and autoimmune atrophic gastritis.

Nitrous oxide is among the most common drugs used by adolescents and young adults, and its neuropsychiatric sequelae are severe but reversible with timely treatment. The causal mechanism relates to impaired metabolism of vitamin B12, which is necessary for the development and maintenance of the myelin sheath. Individuals most susceptible to neuropsychiatric manifestations are those with a secondary cause of vitamin B12 deficiency, including nutritional deficiency and impaired absorption, or an alternative cause of impaired metaboclism. We describe the case of a man in his thirties who developed subacute combined degeneration of the spinal cord and polyneuropathy in the setting of recreational nitrous oxide use and autoimmune atrophic gastritis. Our case highlights clinical pearls for diagnosis and treatment, differential diagnosis, common concomitant aetiologies and the importance of screening for substance use disorder and psychiatric comorbidities.

Methylmalonic acid, vitamin B12, and mortality risk in patients with preexisting coronary heart disease: a prospective cohort study.

BACKGROUND: The inconsistent relationship between Vitamin B12 (B12), methylmalonic acid (MMA, marker of B12 deficiency) and mortality was poorly understood, especially in patients with coronary heart disease (CHD). This study aims to investigate the association of serum MMA, and B12-related biomarkers (serum level, dietary intake, supplement use, and sensibility to B12) with all-cause and cardiovascular mortality in adults with CHD. METHODS: The data of this study were from a subcohort within the US National Health and Nutrition Examination Survey (NHANES). We included adults with preexisting CHD with serum MMA and B12, and dietary B12 intake measurements at recruitment. All participants were followed up until 31 December 2019. Weighted Cox proportional hazard regression was used to estimate hazard ratios (HR) and 95% CI of mortality risk. RESULTS: Overall, 1755 individuals (weighted mean [SE] age, 65.2 [0.5] years; 1047 men [weighted 58.5%]) with CHD were included, with geometric mean levels of serum MMA 182.4 nmol/L, serum B12 494.5 pg/ml, and dietary B12 intake 4.42 mg/day, and percentage of B12 supplements use 39.1%. During a median follow-up of 7.92 years, 980 patients died. Serum B12 concentration, dietary B12 intake and supplements use were not significantly associated with mortality risk (each p ≥ 0.388). In contrast, individuals in the top tertile of MMA had multivariable-adjusted HRs (95% CIs) of 1.70 (1.31-2.20) for all-cause mortality, and 2.00 (1.39-2.89) for cardiovascular mortality (both p trend < 0.001) compared to those in the bottom tertile of MMA. MMA-related mortality risk was particularly higher among participants with sufficient serum B12 (p < 0.001). CHD patients with increased levels of both MMA and B12 had a doubled mortality risk compared to those with lower MMA and B12 (p < 0.001). CONCLUSION: MMA accumulation but not serum or dietary vitamin B12 was associated with increased cardiovascular mortality risk among patients with CHD. This paradox may be related to decreased response to vitamin B12.

Functional vitamin B12 deficiency is a consistent feature in hospital admissions for neurological disorders due to the use of nitrous oxide.

Introduction: Misuse of inhaled nitrous oxide is a growing concern in France. It is known to alter concentrations of vitamin B12, which is required as a cofactor for methionine synthase and methylmalonyl-CoA mutase activity. Hence, measurement of the concentrations of cobalamin metabolism biomarkers, including vitamin B12, homocysteine, and methylmalonic acid, could assist in the management of patients with a complex clinical presentation or in those who deny the consumption of nitrous oxide.Methods: We retrospectively collected clinical and biological data in patients hospitalized for nitrous oxide use in a university hospital in southern France between January 2020 and October 2022.Results: Thirty-one patients were identified during 34 months; 79% were men with a median age of 23.7 years. Most (97%) presented with peripheral polyneuropathy and/or myelopathy. The median vitamin B12 concentration was 134.6 pmol/L, with 17 of 31 patients having values less than 145 pmol/L (the lower limit of the normal range). The median plasma folate concentration was 20.1 nmol/L, which is within the normal range. The median plasma homocysteine concentration was 87.7 µmol/L (normal range <15 µmol/L), and the median plasma methylmalonic acid concentration was 3.8 µmol/L (normal range <0.5 µmol/L).Conclusion: Nitrous oxide use is an emerging public health problem in France, as shown by the number of patients admitted to our hospital. The presence of a functional vitamin B12 deficiency was a consistent feature that could be helpful in diagnosis in complex cases.

A New Case of Association of Megaloblastic Anemia and Pancytopenia of Infants.

BACKGROUND: Vitamin B12, or cobalamin deficiency, an infrequent clinical entity in pediatric age, is found almost solely in breastfed infants whose mothers are purely vegetarian, non-supplemented or with pernicious anemia. Megaloblastic anemia in infants presents with generalized weakness or irritability. METHODS: Diagnosis is usually centered on complete blood count, vitamin dosing, and peripheral smear, which may show macrocytes, hypersegmented neutrophils, reticulocytopenia and a raised mean corpuscular volume (MCV ˃ 100 fL). Pancytopenia has also been noted. RESULTS: We report an exclusive breastfed nine-month-old female child who presented with irritability, developmental delay, and difficulties in introducing new foods. Her initial blood count revealed pancytopenia. Vitamin B12 levels were found to be reduced. Maternal levels of Vitamin B12 were also found to be borderline low. The child was treated as per protocols, and improvement was evidenced with the return of hematological parameters to the regular and gradual advancement of milestones. CONCLUSIONS: We aim to underscore the importance of megaloblastic anemia as an important and rare cause of anemia in infancy.