Detection Of Vitamin B12 Deficiency Research Articles

Maternal Vitamin B12 Deficiency Detected by Newborn Screening-Evaluation of Causes and Characteristics.

Vitamin B12 deficiency, mostly of maternal origin in newborns, is a well-treatable condition but can cause severe neurologic sequelae in infants. Early detection of vitamin B12 deficiency allows the pre-symptomatic treatment of affected children. This evaluation assesses the characteristics of maternal vitamin B12 deficiency detected by newborn screening. In a prospective single-center study, a systematic screening strategy for vitamin B12 deficiency using a combination of two second-tier strategies was applied. In addition to confirmatory diagnostics in children, the systematic work-up of vitamin B12 status was also performed for their mothers. Maternal characteristics were assessed including ethnic origin, diet, and vitamin supplementation during pregnancy. For affected mothers, a work-up by internal medicine was recommended. In total, 121 mother–infant couples were analyzed. 66% of mothers adhered to a balanced diet including meat. The cause of maternal vitamin B12 deficiency was unknown in 56% of cases, followed by dietary causes in 32%, and organic causes in 8%. All mothers following a vegan diet and most mothers with a vegetarian diet took vitamin preparations during pregnancy, whereas only 55.8% of mothers with a balanced diet took folic acid or other vitamins. Maternal vitamin B12, folic acid, and homocysteine levels were significantly correlated with the child’s folic acid levels, and with homocysteine, methylmalonic, and methylcitric acid levels in first and second NBS dried blood spots. Most children had normal blood counts and showed normocytosis. Although 36.7% of mothers showed anemia, only one presented with macrocytosis. Adherence to vitamin supplementation in pregnancy is low despite the recommendation for supplementation of folic acid. Ideally, the evaluation of mothers for vitamin B12 levels and appropriate therapy should be initiated in early pregnancy. In infants detected through newborn screening, the multidisciplinary assessment and therapy of both children and mothers should be performed.

Vitamin B12 Deficiency in Newborns and their Mothers\u2014Novel Approaches to Early Detection, Treatment and Prevention of a Global Health Issue

SummaryVitamin B12 deficiency, mostly of maternal origin in newborns, is a well treatable condition but can cause severe neurologic sequelae. In women of childbearing age and pregnant women worldwide vitamin B12 deficiency has been reported with frequencies of 10%–50%. Children with vitamin B12 deficiency are asymptomatic at birth but may develop severe multisystemic symptoms, including irreversible developmental impairment in the second half-year of life. Early detection of vitamin B12 deficiency allows for presymptomatic treatment. This article provides an overview over the function of vitamin B12 and discusses causes and frequency of vitamin B12 deficiency in newborns, infants, and women of childbearing age. It describes novel successful approaches to newborn screening (NBS) for vitamin B12 deficiency and results of a pilot study which performed systematic NBS for vitamin B12 deficiency using so-called second-tier strategies by measuring homocysteine and methylmalonic acid in dried blood spots. Recommendations for diagnostics in mothers of children with vitamin B12 deficiency are described as well as results of systematic work-up in mothers and treatment and follow-up of children with vitamin B12 deficiency detected by NBS. Treatment options of vitamin B12 deficiency are presented including a newly developed standardized supplementation scheme with exclusively oral vitamin B12 supplementation. Recommendations for preventive approaches to vitamin B12 deficiency for children and mothers are stated. Many children worldwide could benefit from systematic inclusion of vitamin B12 deficiency into NBS panels. In addition, preventive approaches to maternal vitamin B12 deficiency should be implemented systematically during maternal care.

Vitamin B12 deficiency in infants secondary to maternal deficiency: A case series of seven infants

Objective: Vitamin B12 (cobalamin) deficiency can be acquired in infants secondary to exclusive breast feeding from mothers who have undiagnosed vitamin B12 deficiency. We present a case series of seven such patients, describing their clinical presentations, biochemical markers and outcome at follow up. Methods: A retrospective case note review of seven breast-fed infants presenting with signs and symptoms of vitamin B12 deficiency secondary to undiagnosed maternal vitamin B12 deficiency, in a tertiary paediatric neurology centre. Patients were identified by physician recall. Results: Seven cases of vitamin B12 deficiency caused by dietary deficiency were identified. All infants were breast fed. Presenting symptoms included faltering growth, gastro-oesophageal reflux/feeding difficulty, irritability, apnoea, developmental delay or regression and seizures. Range of age of onset of symptoms peaked between 1 and 6 months and the range of age of diagnosis was 3 to 10 months. All infants had methylmalonic aciduria (MMA). Three of their mothers had MMA, one had borderline MMA, and in three mothers MMA is not known. Following treatment with intramuscular vitamin B12, and up to most recent follow-up, three infants continued to have developmental delay, one regained normal development after a prolonged period of delay, one had normal development, one is awaiting first follow-up after treatment, and the other is unknown. Two mothers went on to be diagnosed with pernicious anaemia. Conclusion: Vitamin B12 deficiency has a significant effect on developing infants and not all symptoms are reversible. Early detection of vitamin B12 deficiency can allow early treatment and potentially mitigate long-term neurological sequelae. We recommend testing mothers in the third trimester of pregnancy for vitamin B12 level and/or MMA. This would enable supplementation of vitamin B12 for mother, for the benefit of the foetus/infant and early identification of vitamin B12 deficiency in the infant.

Vitamin B12 Deficiency with the Absence of Anemia in Young and Middle-Aged Population

Vitamin B12 deficiency with macrocytic anemia is a well-known clinical entity. However the clinical importance of the vitamin B12 insufficiency without any hematological abnormality is underestimated in the adult patient population. The aim of this study is to assess frequency of vitamin B12 deficiency with normal complete blood counts (CBC) in adult subjects. Within the 1-year long period, the adult patients among the ones that had applied to Hacettepe University Hospitals were included in the study, in whom the vitamin B12 deficiency was detected. The patients, whose vitamin B12 values were <200 pg/ml were covered in the study. To identify the ages, genders, complete blood cell count values, the parameters of anemia, homocysteine values, were scanned and assessed. In sum, 4077 patients, in whom vitamin B12 deficiency had been detected were included in our study. Later, the patients were separated into two sub-groups, young and middle-aged patients, whose ages were between 17 and 49 (n= 2186). 71.3% of the 2186 young and mid-aged patients consisted of women while 28,7% consisted of men. The rest of the patients had vitamin B12 deficiency without any hematological abnormalities. Homocysteine level, which was recommended as a verification testing method was monitored in 14% of the patients. Significantly low levels of vitamin B12 were detected in the adult population without anemia, in study. The detection of vitamin B12 deficiency with normal CBC requires early intervention for both clinical diagnostic and/or therapeutic approaches.The verification tests required for final diagnosis.

Algorithm for the early diagnosis of vitamin B12 deficiency in elderly people.

The elderly population is particularly at risk for developing vitamin B12-deficiency. Serum cobalamin does not necessarily reflect a normal B12 status. The determination of methylmalonic acid is not available in all laboratories. Issues of sensitivity for holotranscobalamin and the low specificity of total homocysteine limit their utility. The aim of the present study is to establish a diagnostic algorithm by using a combination of these markers in place of a single measurement. We compared the diagnostic efficiency of these markers for detection of vitamin B12 deficiency in a population (n = 218) of institutionalized elderly (median age 80 years). Biochemical, haematological and morphological data were used to categorize people with or without vitamin B12 deficiency. In receiver operating curves characteristics for detection on vitamin B12 deficiency using single measurements, serum folate has the greatest area under the curve (0.87) and homocysteine the lowest (0.67). The best specificity was observed for erythrocyte folate and methylmalonic acid (100% for both) but their sensitivity was very low (17% and 53%, respectively). The highest sensitivity was observed for homocysteine (81%) and serum folate (74%). When we combined these markers, starting with serum and erythrocyte folate, followed by holotranscobalamin and ending by methylmalonic acid measurements, the overall sensitivity and specificity of the algorithm were 100% and 90%, respectively. The proposed algorithm, which combines erythrocyte folate, serum folate, holotranscobalamin and methylmalonic acid, but eliminate B12 and tHcy measurements, is a useful alternative for vitamin B12 deficiency screening in an elderly institutionalized cohort.

Methylmalonic acid and homocysteine assessment in the detection of vitamin B12 deficiency in patients with bilateral visual loss ‐ authors’ reply

Methylmalonic acid and homocysteine assessment in the detection of vitamin B12 deficiency in patients with bilateral visual loss ‐ authors’ reply

Detection of vitamin B12 deficiency in alcohol abuse

Detection of vitamin B12 deficiency in alcohol abuse

Utility and limitations of biochemical markers of vitamin B12 deficiency

There is an urgent need for proper utilization of laboratory markers to diagnose vitamin B12 deficiency that should reduce false negative cases. We worked out a diagnostic algorithm that provides a two-step detection of vitamin B12 deficiency using holotranscobalamin as a first line marker and methylmalonic acid (MMA) as a second line marker. We tested 1359 serum samples sent to our laboratory for total vitamin B12 assay. Serum samples were used for the determination of holotranscobalamin, MMA and creatinine. Compared with total B12, holotranscobalamin showed a higher area under the receiver operating characteristic curve for detecting MMA levels > 300 nM. However, the distribution of holotranscobalamin in individuals with elevated creatinine irrespective of MMA and in individuals with elevated MMA irrespective of creatinine was shifted into the higher ranges. In the grey zone of holotranscobalamin between 23 and 75 pM (the range extending from the 90% diagnostic sensitivity to the 90% diagnostic specificity), MMA testing as a second line marker would help detecting 18% of deficient cases. Lowering MMA after vitamin B12 treatment may help setting the diagnosis of B12 deficiency in individuals with elevated creatinine. Testing for vitamin B12 deficiency should start with holotranscobalamin measurement. Holotranscobalamin between 23 and 75 pM should be followed by MMA testing that can filter substantial number of deficient cases in the grey range in individuals with normal renal function. This diagnostic strategy may significantly improve assessing vitamin B12 deficiency.

Methylmalonic acid and homocysteine assessment in the detection of vitamin B12 deficiency in patients with bilateral visual loss

Editor, In neuro-ophthalmology, vitamin B12 deficiency is a known cause for bilateral visual loss because of an optic neuropathy. Traditionally, the diagnosis of vitamin B12 deficiency has been based on clinical symptoms and on the determination of serum vitamin B12 levels. However, more recent studies have given evidence that measurements of serum methylmalonic acid (MMA) and homocysteine (HC) are more sensitive in the determination of a deficient state for vitamin B12 at tissue level (Savage et al. 1994; Stabler 1995). MMA and HC are metabolites that accumulate when the vitamin B12-dependent enzymatic reactions in human cells dysfunction. The aim of the present case series is to draw attention within the ophthalmologic community to the new insights in detection of vitamin B12 deficiency. We present a case series of seven patients with a bilateral optic neuropathy and an elevated MMA and/or HC level as evidence of a vitamin B12 deficiency. The patients were seen at our department between January 2009 and December 2010. Whenever a vitamin B12 level was determined to exclude a vitamin B12 deficiency as the cause of the bilateral optic neuropathy, serum MMA and, in most cases, HC were also measured. The values of serum vitamin B12, MMA and HC are shown in Table 1. In only three patients, the serum vitamin B12 level was below the established norm set by the laboratory. Present literature recommends measuring MMA and/or HC whenever vitamin B12 is below 200 or 300 pmol/l (Stabler 1995; Oh & Brown 2003). However, had we followed these recommendations, still three patients with a deficient state for vitamin B12 would have been missed. All patients received vitamin B12 substitution therapy. In the four patients where we repeated the measurement of MMA and HC after treatment, the metabolites normalized indicating that the abnormal levels of metabolites were indeed caused by the vitamin B12 deficiency. Two of the patients with an apparent normal B12 serum level had a history of alcohol abuse. Lambert et al. (1997) reported on patients suffering from alcoholic liver cirrhosis. These patients had normal to elevated serum vitamin B12, probably due to intracellular release of stored vitamin B12 from damaged liver cells. But they also had elevated MMA and HC, indicating a vitamin B12 deficiency at tissue level. They suggested poor cellular penetration of vitamin B12 owing to a deficit or malfunction of binding protein as an explanation for their results. Another striking finding in the present series is that two of seven patients had a pathogenic mutation for Leber hereditary optic neuropathy (LHON). LHON and optic neuropathy as a result of vitamin B12 deficiency have clinical similarities, and both diseases have their origin in mitochondrial metabolism. So it is conceivable that a subclinical vitamin B12 deficiency can trigger the expression of optic neuropathy in LHON patients. Reports on patients with both a LHON mutation and vitamin B12 deficiency have been published in the past (Pott & Wong 2006). The earliest descriptions of optic neuropathy in vitamin B12 deficiency are in patients with pernicious anaemia. However, this classical entity did not occur in any of the patients presented in this study. Two patients had proven macrocytosis, without anaemia. Five patients did not have macrocytosis or anaemia. Accompanying neurological symptoms were only present in two patients. The present results again point out that macrocytosis or neurological symptoms are not a requisite finding to suspect a vitamin B12 deficiency. In conclusion, the results of this study confirm that measurement of only vitamin B12 serum level will miss neuro-ophthalmologic patients with an actual deficiency. One should always measure MMA and HC levels when a vitamin B12 deficiency is suspected.

Indicators for Assessing Folate and Vitamin B12 Status and for Monitoring the Efficacy of Intervention Strategies

Deficiencies of folate or of vitamin B12 are widespread and constitute a major global burden of morbidity affecting all age groups. Detecting or confirming the presence of folate or vitamin B12 deficiency and distinguishing one from the other depends, ultimately, on laboratory testing. Tests to determine the presence of folate or vitamin B12 deficiency are used singly or in combination to establish the nutritional status and prevalence of deficiencies of the vitamins in various populations. The efficacy of interventions through the use of fortification or supplements is monitored using the same laboratory tests. Tests currently in use have limitations that can be either technical or have a biological basis. Consequently, each single test cannot attain perfect sensitivity, specificity, or predictive value. Laboratory indicators of vitamin B12 or folate status involve measurement of either the total or a physiologically relevant fraction of the vitamin in a compartment such as the blood. Thus, assays to measure vitamin B12 or folate in plasma or serum as well as folate in red blood cells are in widespread use, and more recently, methods to measure vitamin B12 associated with the plasma binding protein transcobalamin (holotranscobalamin) have been developed. Alternatively, levels of surrogate biochemical markers that reflect the metabolic function of the vitamin can be used. Surrogates most commonly used are plasma homocysteine, for detection of either vitamin B12 or folate deficiency and methylmalonic acid for detection of vitamin B12 deficiency. The general methods as well as their uses, indications, and limitations are presented.

Detection of Vitamin B12 Deficiency in Older People by Measuring Vitamin B12 or the Active Fraction of Vitamin B12, Holotranscobalamin

Impaired vitamin B(12) function and decreased vitamin B(12) status have been associated with neurological and cognitive impairment. Current assays analyze total vitamin B(12) concentration, only a small percentage of which is metabolically active. Concentrations of this active component, carried on holotranscobalamin (holoTC), may be of greater relevance than total vitamin B(12). We compared the utility of serum holoTC with conventional vitamin B(12) for detection of vitamin B(12) deficiency in a population-based study of older people, using increased methylmalonic acid (MMA) concentrations as a marker of metabolic vitamin B(12) deficiency in the overall population (n = 2403) and in subsets with normal (n = 1651) and abnormal (n = 752) renal function. Among all participants, 6% had definite (MMA >0.75 micromol/L) and 16% had probable (MMA >0.45 micromol/L) metabolic vitamin B(12) deficiency. In receiver operating characteristic curves for detection of definite vitamin B(12) deficiency, holoTC had a greater area under the curve (AUC) compared with vitamin B(12) in all participants (0.85 vs 0.76; P <0.001) and in subsets with normal (AUC: 0.87 vs 0.79; P <0.001) and abnormal (AUC: 0.85 vs 0.74; P = 0.002) renal function. Similar findings were observed for detection of moderate vitamin B(12) deficiency. Whereas the positive predictive value for both holoTC and vitamin B(12) was greater for detection of probable than definite vitamin B(12) deficiency, both tests were associated with more false-positive than true-positive test results. HoloTC has a modestly superior diagnostic accuracy compared with conventional vitamin B(12) for the detection of vitamin B(12) deficiency, but neither test can be recommended to screen asymptomatic populations.

Vitamin B12 and folate after 5-12 years of continent ileal urostomy (Kock reservoir) in children and adolescents.

To assess B12 and folate deficiency after continent urinary diversion via a Kock continent urinary reservoir in children and adolescents. Ten boys and 10 girls (10.8-18 years old at surgery) were operated with a Kock reservoir and followed for 5-12 years (mean 8.5). The follow-up period was divided into early (3 months-5 years, EFU) and late (5-12 years, LFU) follow-up. Patients were investigated for haemoglobin, serum iron, total iron binding capacity (TIBC), serum Vitamin B12, serum and blood folate, methylmalonic acid (MMA), homocystine and glomerular filtration rate. Two patients developed subnormal B12 values (median 107.5 pmol/l), one at the EFU, and the other at LFW. The B12 value decreased during the LFU compared to the EFU in nine patients, but it was still within the normal range. Two patients with renal impairment had elevated MMA with normal B12 values. Five patients had high values of homocystine with folate deficiency and/or B12 deficiency and renal impairment. Plasma folate mean value was normal during the whole follow-up. Blood folate was below normal in five patients at the EFU. Two of these five patients, in addition to three patients, had low values at the LFU. Three of four patients with remaining short terminal ileum (20-45 cm) had normal B12 values at both the EFU & LFU and one had low values at the LFU. Six patients had subnormal GFR at the LFU. To a similar degree as in adults, Vitamin B12, folate and iron deficiency can occur in children and adolescents after continent urinary diversion using an ileal segment. Therefore, Vitamin B12 and folate should be monitored regularly in these patients. Serum MMA and homocystine may offer increased detection of Vitamin B12 deficiency, especially in the patients with normal renal function. Vitamin B12 deficiency is neither correlated with the time elapsed since surgery, nor with the ileum length. Patients are usually asymptomatic, so patients with true B12 deficiency should be identified and placed on life-long Vitamin B12 therapy. An adequate synthetic folic acid as supplements or fortified food is recommended for patients with folate deficiency.

Determination of Methylmalonic Acid by High-Performance Liquid Chromatography

An isocratic reverse-phase C18 high-performance liquid chromatography (HPLC) technique for methylmalonic acid (MMA) with fluorescence detection is described. MMA is extracted from an acidified sample (plasma, urine, etc.) with ethyl acetate. The extract is dried and derivatized with monodansylcadaverine and dicyclohexylcarbodiimide prior to injection on the HPLC. Ethylmalonic acid is used as an internal standard. Evaluation of the technique was with ovine blood plasma, liver, rumen fluid, and urine. The technique can quantitate as little as 0.2 μmol/liter MMA in samples (based on 10 times the detection limit) and is therefore sufficiently sensitive to measure levels in normal blood plasma. The method is rapid, with up to 60 samples per day throughput, and so is suitable as a routine diagnostic test for the detection of vitamin B12 deficiency.