Understanding the challenges, unmet needs, and expectations of mucopolysaccharidoses I, II and VI patients and their caregivers in France: a survey study.

BACKGROUND: Mucopolysaccharidoses (MPS) are a group of inherited lysosomal storage diseases caused by defective enzyme activity involved in the catalysis of glycosaminoglycans. Published data on adult patients with MPS remains scarce. Therefore, the present qualitative survey study was aimed at understanding knowledge of the disease, unmet needs, expectations, care, and overall medical management of adult/adolescent patients with MPS I, II and VI and their caregivers in France. RESULTS: A total of 25 patients (MPS I, np = 11; MPS II, np = 9; MPS VI, np = 5) were included and about 36 in-depth interviews (caregivers alone, nc = 8; patients-caregiver pair, nc+p = 22; patients alone, np = 6) were conducted. Except one (aged 17 years), all patients were adults (median age: 29 years [17-50]) and diagnosed at median age of 4 years [0.4-30], with mainly mothers as caregivers (nc = 16/19). Patients were classified into three groups: Group A, Patients not able to answer the survey question because of a severe cognitive impairment (np = 8); Group B, Patients able to answer the survey question with low or no cognitive impairment and high motor disability (np = 10); and Group C, Patients able to answer the survey question with low or no cognitive impairment and low motor disability (np = 7). All groups were assessed for impact of disease on their daily lives based on a scale of 0-10. Caregivers in Group A were found to be most negatively affected by the disease, except for professional activity, which was most significantly impacted in Group B (4.7 vs. 5.4). The use of orthopaedic/medical equipments, was more prevalent in Groups A and B, versus Group C. Pain management was one of the global unmet need expressed by all groups. Group A caregivers expected better support from childcare facilities, disability clinics, and smooth transition from paediatric care to adult medicine. Similarly, Group B caregivers expected better specialised schools, whereas Group C caregivers expected better psychological support and greater flexibility in weekly infusion schedules for their patients. CONCLUSIONS: The survey concluded that more attention must be paid to the psychosocial status of patients and caregivers. The preference for reference centre for follow-up and treatment, hospitalizations and surgeries were evident. The most significant needs expressed by the patients and caregivers include better understanding of the disease, pain management, monitoring of complications, flexibility in enzyme replacement therapy, home infusions especially for attenuated patients, and improved transitional support from paediatric to adult medicine.

Sphingosine-1-Phosphate Levels Are Higher in Male Patients with Non-Classic Fabry Disease.

Fabry disease is an X-linked lysosomal disease in which defects in the alpha-galactosidase A enzyme activity lead to the ubiquitous accumulation of glycosphingolipids. Whereas the classic disease is characterized by neuropathic pain, progressive renal failure, white matter lesions, cerebral stroke, and hypertrophic cardiomyopathy (HCM), the non-classic phenotype, also known as cardiac variant, is almost exclusively characterized by HCM. Circulating sphingosine-1-phosphate (S1P) has controversially been associated with the Fabry cardiomyopathy. We measured serum S1P levels in 41 patients of the FFABRY cohort. S1P levels were higher in patients with a non-classic phenotype compared to those with a classic phenotype (200.3 [189.6−227.9] vs. 169.4 ng/mL [121.1−203.3], p = 0.02). In a multivariate logistic regression model, elevated S1P concentration remained statistically associated with the non-classic phenotype (OR = 1.03; p < 0.02), and elevated lysoGb3 concentration with the classic phenotype (OR = 0.95; p < 0.03). S1P levels were correlated with interventricular septum thickness (r = 0.46; p = 0.02). In a logistic regression model including S1P serum levels, phenotype, and age, age remained the only variable significantly associated with the risk of HCM (OR = 1.25; p = 0.001). S1P alone was not associated with cardiac hypertrophy but with the cardiac variant. The significantly higher S1P levels in patients with the cardiac variant compared to those with classic Fabry suggest the involvement of distinct pathophysiological pathways in the two phenotypes. S1P dosage could allow the personalization of patient management.

Loss of thymidine phosphorylase activity disrupts adipocyte differentiation and induces insulin-resistant lipoatrophic diabetes.

BACKGROUND: Thymidine phosphorylase (TP), encoded by the TYMP gene, is a cytosolic enzyme essential for the nucleotide salvage pathway. TP catalyzes the phosphorylation of the deoxyribonucleosides, thymidine and 2'-deoxyuridine, to thymine and uracil. Biallelic TYMP variants are responsible for Mitochondrial NeuroGastroIntestinal Encephalomyopathy (MNGIE), an autosomal recessive disorder characterized in most patients by gastrointestinal and neurological symptoms, ultimately leading to death. Studies on the impact of TYMP variants in cellular systems with relevance to the organs affected in MNGIE are still scarce and the role of TP in adipose tissue remains unexplored. METHODS: Deep phenotyping was performed in three patients from two families carrying homozygous TYMP variants and presenting with lipoatrophic diabetes. The impact of the loss of TP expression was evaluated using a CRISPR-Cas9-mediated TP knockout (KO) strategy in human adipose stem cells (ASC), which can be differentiated into adipocytes in vitro. Protein expression profiles and cellular characteristics were investigated in this KO model. RESULTS: All patients had TYMP loss-of-function variants and first presented with generalized loss of adipose tissue and insulin-resistant diabetes. CRISPR-Cas9-mediated TP KO in ASC abolished adipocyte differentiation and decreased insulin response, consistent with the patients' phenotype. This KO also induced major oxidative stress, altered mitochondrial functions, and promoted cellular senescence. This translational study identifies a new role of TP by demonstrating its key regulatory functions in adipose tissue. CONCLUSIONS: The implication of TP variants in atypical forms of monogenic diabetes shows that genetic diagnosis of lipodystrophic syndromes should include TYMP analysis. The fact that TP is crucial for adipocyte differentiation and function through the control of mitochondrial homeostasis highlights the importance of mitochondria in adipose tissue biology.

Challenging the traditional approach for interpreting genetic variants: Lessons from Fabry disease.

Fabry disease (FD) is an X-linked genetic disease due to pathogenic variants in GLA. The phenotype varies depending on the GLA variant, alpha-galactosidase residual activity, patient's age and gender and, for females, X chromosome inactivation. Over 1000 variants have been identified, many through screening protocols more susceptible to disclose non-pathogenic variants or variants of unknown significance (VUS). This, together with the non-specificity of some FD symptoms, challenges physicians attempting to interpret GLA variants. The traditional way to interpreting pathogenicity is based on a combined approach using allele frequencies, genomic databases, global and disease-specific clinical databases, and in silico tools proposed by the American College of Medical Genetics and Genomics. Here, a panel of FD specialists convened to study how expertise may compare with the traditional approach. Several GLA VUS, highly controversial in the literature (p.Ser126Gly, p.Ala143Thr, p.Asp313Tyr), were re-analyzed through reviews of patients' charts. The same was done for pathogenic GLA variants with some specificities. Our data suggest that input of geneticists and physicians with wide expertise in disease phenotypes, prevalence, inheritance, biomarkers, alleles frequencies, disease-specific databases, and literature greatly contribute to a more accurate interpretation of the pathogenicity of variants, bringing a significant additional value over the traditional approach.

Adult-onset diagnosis of urea cycle disorders: Results of a French cohort of 71 patients.

Urea cycle disorders (UCD) are rare diseases that usually affect neonates or young children. During decompensations, hyperammonemia is neurotoxic, leading to severe symptoms and even coma and death if not treated rapidly. The aim was to describe a cohort of patients with adult onset of UCDs in a multicentric, retrospective and descriptive study of French adult patients with a diagnosis after 16 years of age of UCDs due to a deficiency in one of the 6 enzymes (arginase, ASL, ASS, CPS1, NAGS, OTC) or the two transporters (ORNT1 or citrin). Seventy-one patients were included (68% female, 32% male). The diagnosis was made in the context of (a) a metabolic decompensation (42%), (b) family history (55%), or (c) chronic symptoms (3%). The median age at diagnosis was 33 years (range 16-86). Eighty-nine percent of patients were diagnosed with OTC deficiency, 7% CPS1 deficiency, 3% HHH syndrome and 1% argininosuccinic aciduria. For those diagnosed during decompensations (including 23 OTC cases, mostly female), 89% required an admission in intensive care units. Seven deaths were attributed to UCD-6 decompensations and 1 epilepsy secondary to inaugural decompensation. This is the largest cohort of UCDs diagnosed in adulthood, which confirms the triad of neurological, gastrointestinal and psychiatric symptoms during hyperammonemic decompensations. We stress that females with OTC deficiency can be symptomatic. With 10% of deaths in this cohort, UCDs in adults remain a life-threatening condition. Physicians working in adult care must be aware of late-onset presentations given the implications for patients and their families.

Cornea verticillata and acroparesthesia efficiently discriminate clusters of severity in Fabry disease.

BACKGROUD: Fabry disease (OMIM #301 500), the most prevalent lysosomal storage disease, is caused by enzymatic defects in alpha-galactosidase A (GLA gene; Xq22.1). Fabry disease has historically been characterized by progressive renal failure, early stroke and hypertrophic cardiomyopathy, with a diminished life expectancy. A nonclassical phenotype has been described with an almost exclusive cardiac involvement. Specific therapies with enzyme substitution or chaperone molecules are now available depending on the mutation carried. Numerous clinical and fundamental studies have been conducted without stratifying patients by phenotype or severity, despite different prognoses and possible different pathophysiologies. We aimed to identify a simple and clinically relevant way to classify and stratify patients according to their disease severity. METHODS: Based on data from the French Fabry Biobank and Registry (FFABRY; n = 104; 54 males), we applied unsupervised multivariate statistics to determine clusters of patients and identify clinical criteria that would allow an effective classification of adult patients. Thanks to these criteria and empirical clinical considerations we secondly elaborate a new score that allow the severity stratification of patients. RESULTS: We observed that the absence of acroparesthesia or cornea verticillata is sufficient to classify males as having the nonclassical phenotype. We did not identify criteria that significantly cluster female patients. The classical phenotype was associated with a higher risk of severe renal (HR = 35.1; p <10-3) and cardiac events (HR = 4.8; p = 0.008) and a trend toward a higher risk of severe neurological events (HR = 7.7; p = 0.08) compared to nonclassical males. Our simple, rapid and clinically-relevant FFABRY score gave concordant results with the validated MSSI. CONCLUSION: Acroparesthesia and cornea verticillata are simple clinical criteria that efficiently stratify Fabry patients, defining 3 different groups: females and males with nonclassical and classical phenotypes of significantly different severity. The FFABRY score allows severity stratification of Fabry patients.

A Proteomics-Based Analysis Reveals Predictive Biological Patterns in Fabry Disease.

Background: Fabry disease (FD) is an X-linked progressive lysosomal disease (LD) due to glycosphingolipid metabolism impairment. Currently, plasmatic globotriaosylsphingosine (LysoGb3) is used for disease diagnosis and monitoring. However, this biomarker is inconstantly increased in mild forms and in some female patients. Materials and Methods: We applied a targeted proteomic approach to explore disease-related biological patterns that might explain the disease pathophysiology. Forty proteins, involved mainly in inflammatory and angiogenesis processes, were assessed in 69 plasma samples retrieved from the French Fabry cohort (FFABRY) and from 83 healthy subjects. For predictive performance assessment, we also included other LD samples (Gaucher, Pompe and Niemann Pick C). Results: The study yielded four discriminant proteins that include three angiogenesis proteins (fibroblast growth factor 2 (FGF2), vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor C (VEGFC)) and one cytokine interleukin 7 (IL-7). A clear elevation of FGF2 and IL-7 concentrations was observed in FD compared to other LD samples. No correlation was observed between these proteins and globotriaosylsphingosine (LysoGb3). A significant correlation exists between IL-7 and residual enzyme activity in a non-classical phenotype. This highlights the orthogonal biological information yielded by these proteins that might help in stratifying Fabry patients. Conclusion: This work highlights the potential of using proteomics approaches in exploring FD and enhancing FD diagnosis and therapeutic monitoring performances.

Treatment needs and expectations for Fabry disease in France: development of a new Patient Needs Questionnaire.

BACKGROUND: Fabry disease (FD) is a rare, X-linked, inherited lysosomal disease caused by absent or reduced α-galactosidase A activity. Due to the heterogeneity of disease presentation and progression, generic patient-reported outcome (PRO) tools do not provide accurate insight into patients' daily lives and impact of disease specific treatments. Also, the French National Health Authority, (HAS) actively encourages a patient-centric approach to improve the quality of care throughout the patient journey. In response to this initiative, we aimed to develop and validate a specific, self-reported, Patient Needs Questionnaire for people living with Fabry disease to appraise patient needs and expectations towards their treatment (PNQ Fabry). This endeavour was led with the help of French patient associations (APMF & VML) and dedicated expert centres. PNQ Fabry was developed according to the FDA/EMA methodologies and best practices for the development of PRO tools in rare diseases. Our approach comprised of three steps, as follows: concept elicitation and item generation, item reduction, and final validation of the questionnaire through a two-stage survey. RESULTS: Intrinsic and extrinsic reliability was established, using a validated benchmark questionnaire. With the invaluable help of patient associations, we recruited a satisfactory population in this rare disease setting, to ensure robust participation to validate our PNQ (final number of questionnaires: 76). At the end of the process, a 26-item patient-reported questionnaire was obtained with excellent psychometric properties, exhibiting very satisfactory measurement outcomes for reliability and validity. The results of this initiative demonstrate that the PNQ Fabry is accurate, suitable and tailored to FD patients, as it addresses themes identified during patient interviews, that were further validated through statistical analyses of quantitative surveys. An ongoing phase IV study is using this tool. CONCLUSION: We believe the PNQ Fabry will be a reliable and insightful tool in clinical practice, to improve patient management in FD.

Coagulation Parameters in Adult Patients With Type-1 Gaucher Disease.

BACKGROUND: Gaucher disease is a rare inborn error of lysosomal metabolism, characterized by lysosomal storage of the ß-glucosylceramide. Bleedings observed in type-1 Gaucher disease (GD1) are commonly attributed to a low platelet count, but they can also occur when the platelet count is normal or slightly low. Abnormal platelet function has been described and deficiencies in coagulation factors too, such as factors II, V, VII, VIII, IX, X, XI, XII, and von Willebrand factor. However, studies are few in number, involving few patients and having varying conclusions. The aim of this study was to analyze clotting factor deficiencies in a larger cohort of French patients with GD1. METHODS: This is an observational national study. The coagulation parameters were collected during routine GD1 monitoring and described retrospectively. RESULTS: We highlighted low levels of various coagulation factors in 46% of the patients with GD1. The most frequent coagulation abnormalities encountered were factor V, X, XI, and XII deficiencies. Deficits were usually mild and coagulation abnormalities tended to be more frequent in non-splenectomized patients. CONCLUSIONS: In conclusion, frequent and varied coagulation abnormalities were found in a high proportion of GD1 patients.

Deep characterization of the anti-drug antibodies developed in Fabry disease patients, a prospective analysis from the French multicenter cohort FFABRY.

BACKGROUND: Fabry disease (OMIM #301500) is an X-linked disorder caused by alpha-galactosidase A deficiency with two major clinical phenotypes: classic and non-classic of different prognosis. From 2001, enzyme replacement therapies (ERT) have been available. We aimed to determine the epidemiology and the functional characteristics of anti-drug antibodies. Patients from the French multicenter cohort FFABRY (n = 103 patients, 53 males) were prospectively screened for total anti-agalsidase IgG and IgG subclasses with a home-made enzyme-linked immunosorbent assay (ELISA), enzyme-inhibition assessed with neutralization assays and lysoGb3 plasma levels, and compared for clinical outcomes. RESULTS: Among the patients exposed to agalsidase, 40% of men (n = 18/45) and 8% of women (n = 2/25) had antibodies with a complete cross-reactivity towards both ERTs. Antibodies developed preferentially in men with non-missense GLA mutations (relative risk 2.88, p = 0.006) and classic phenotype (58.6% (17/29) vs 6.7% (1/16), p = 0.0005). Specific anti-agalsidase IgG1 were the most frequently observed (16/18 men), but the highest concentrations were observed for IgG4 (median 1.89 µg/ml, interquartile range (IQR) [0.41-12.24]). In the men exposed to agalsidase, inhibition was correlated with the total IgG titer (r = 0.67, p < 0.0001), especially IgG4 (r = 0.75, p = 0.0005) and IgG2 (r = 0.72, p = 0.001). Inhibition was confirmed intracellularly in Fabry patient leucocytes cultured with IgG-positive versus negative serum (median: 42.0 vs 75.6%, p = 0.04), which was correlated with IgG2 (r = 0.67, p = 0.017, n = 12) and IgG4 levels (r = 0.59, p = 0.041, n = 12). Plasma LysoGb3 levels were correlated with total IgG (r = 0.66, p = 0.001), IgG2 (r = 0.72, p = 0.004), IgG4 (r = 0.58, p = 0.03) and IgG1 (r = 0.55, p = 0.04) titers. Within the classic group, no clinical difference was observed but lysoGb3 levels were higher in antibody-positive patients (median 33.2 ng/ml [IQR 20.6-55.6] vs 12.5 [10.1-24.0], p = 0.005). CONCLUSION: Anti-agalsidase antibodies preferentially develop in the severe classic Fabry phenotype. They are frequently associated with enzyme inhibition and higher lysoGb3 levels. As such, they could be considered as a hallmark of severity associated with the classic phenotype. The distinction of the clinical phenotypes should now be mandatory in studies dealing with Fabry disease and its current and future therapies.

Regressive pyridoxine-induced sensory neuronopathy in a patient with homocystinuria.

Pyridoxine (vitamin B6) is an essential vitamin playing a crucial role in amino acid metabolism. Pyridoxine is used for isoniazid side-effects prevention, pyridoxine-dependent epilepsy treatment and cystathionine beta-synthase deficiency (homocystinuria) treatment. However, vitamin B6 hypervitaminosis is neurotoxic and may provoke a progressive sensory neuronopathy (sensory ganglionopathy), usually when daily uptake is above 50 mg. We describe the case of a 30-year-old patient with homocystinuria who was treated with pyridoxine 1250-1750 mg/day for 20 years and developed progressive sensory neuropathy with ataxia and impaired sensation in the extremities. Electrodiagnostic testing demonstrated non-length-dependent abnormalities of sensory nerve potentials, and sensory ganglionopathy was diagnosed. Pyridoxine dosage was reduced to 500 mg/day, resulting in the disappearance of sensory symptoms and ataxia, and the normalisation of sensory nerve potentials. Our case indicates that pyridoxine-induced sensory ganglionopathy may be reversible, even after prolonged ingestion of high doses of vitamin B6 for more than 20 years.

Respiratory Complications Lead to the Diagnosis of Chronic Granulomatous Disease in Two Adult Patients.

Chronic granulomatous disease (CGD) is a primary immunodeficiency associated to multiple life-threatening bacterial and fungal infections, beginning in childhood. There are rare cases of diagnosis in adulthood. We describe here two cases of late diagnosis in adults: a 45-year-old woman and 59-year-old-man. CGD diagnosis should be considered in adult patients with unexplained infectious diseases with tissue granuloma.

Food-cobalamin malabsorption in elderly patients: clinical manifestations and treatment.

PURPOSE: Approximately 15% of people aged more than 60 years old have a cobalamin (vitamin B12) deficiency, mainly in relation with food-cobalamin malabsorption (FCM). To date, no study has documented this disorder in the elderly. There is also little information on clinical consequences. SUBJECTS AND METHODS: We studied 92 elderly patients with well-established FCM who were extracted from an observational cohort study (1995-2004) of 172 consecutive elderly patients with documented cobalamin deficiency. RESULTS: The median patient age was 76 +/- 8 years; 60 patients were women. The most common clinical manifestations were neurologic or psychologic: mild sensory polyneuropathy (44.6%), confusion or impaired mental functioning (22.8%), and physical asthenia (20.7%). Hematologic abnormalities were reported in at least one third of the patients: anemia (21%), leukopenia (10.9%), thrombopenia (8.7%), and pancytopenia (6.5%). All patients had low serum vitamin B12 levels (<200 pg/mL), with a mean value (+/- standard deviation) of 131 +/- 38 pg/mL and total serum homocysteine level of 22.1 +/- 9.3 micromol/L. The mean hemoglobin level was 10.9 +/- 2.5 g/dL and the mean erythrocyte cell volume 95.7 +/- 12.7 fL. Correction of the serum vitamin B12 levels and hematologic abnormalities was achieved equally well in patients treated with either intramuscular or oral crystalline cyanocobalamin. CONCLUSIONS: This study suggests that in elderly patients, FCM may be associated with significant neurologic, psychologic, and hematologic abnormalities, which seem to respond equally well to either oral or parenteral vitamin B12 therapy.

[Recurrent facial palsy, primary Gougerot-Sjögren's syndrome and vitamin B12 deficiency]. / Paralysie faciale récidivante, syndrome de Gougerot-Sjögren primitif et carence en vitamine B12.

INTRODUCTION: Differing cranial nerve involvement has been reported in the context of Gougerot-Sjögren's syndrome. Involvement of the V, III and VII nerves has been reported, the most characteristic being nerve V, notably its lower branch. Rare, well documented, cases of facial palsy have also been described. OBSERVATION: Recurrent facial palsy in a 40 year-old woman revealed a primary Sjögren's syndrome and vitamin B12 deficiency. DISCUSSION: The onset of facial palsy has been linked with Gougerot-Sjögren's syndrome. The contribution of vitamin B12 deficiency is discussed.

Effects of oral crystalline cyanocobalamin 1000 µg/d in the treatment of pernicious anemia: An open-label, prospective study in Ten Patients.

BACKGROUND: Standard treatment of cobalamin (vitamin B12) deficiency involvesregular (1000 µg/mo) IM cyanocobalamin administration. It has been suggested that high-dose (>2000 µg/d) oral cyanocobalamin may be effective in patients with pernicious anemia. OBJECTIVE: The aim of this study was to assess the efficacy and tolerability of oral crystalline cyanocobalamin 1000 µg/d in patients with cobalamin deficiency related to established pernicious anemia. METHODS: This open-label, prospective study was conducted at StrasbourgUniversity Hospital, Strasbourg, France. Patients aged ≥18 years with well-documented cobalamin deficiency related to pernicious anemia were enrolled. Patients received crystalline cyanocobalamin 1000 µg QD PO (capsule) for at least 3 months. Serum cobalamin, folate, iron, and homocysteine concentrations were measured, and a complete blood count was obtained, before (month 0; baseline) and after treatment. RESULTS: Ten patients (7 women, 3 men; mean [SD] age, 72.1 [15.5] years) entered the study. After 3 months of treatment, serum cobalamin concentration increased in all 9 patients in whom it was measured (mean [SD] increase, 117.4 [30.8] pg/mL; P < 0.001 vs baseline). Serum cobalamin concentrations were normalized (>200 pg/mL) in 6 patients. The serum cobalamin concentration was unavailable in 1 patient because of technical problems. Eight patients had increased hemoglobin concentrations (mean [SD] increase, 2.5 [2.4] g/dL; P < 0.01 vs baseline). All 10 patients had decreased mean erythrocyte corpuscular volumes (mean [SD] decrease, 10.4 [6.2] fL; P < 0.003 vs baseline). Four patients received concomitant blood transfusions or folate and iron supplementation. Three patients experienced clinical improvement in paresthesia, reflex abolition, or combined medullary sclerosis (each, 1 patient). CONCLUSION: The results of this small study in patients with cobalamin deficiencyrelated to pernicious anemia suggest that oral crystalline cyanocobalamin 1000 µg/d may be an effective treatment.

Prognostic factors of hematological recovery in life-threatening nonchemotherapy drug-induced agranulocytosis. A study of 91 patients from a single center.

OBJECTIVES: We studied clinical factors that may influence the duration of hematological recovery to reach neutrophil counts and thus, indirectly, the prognosis in patients with life-threatening drug-induced agranulocytosis (DIA). METHODS: Using univariate and multivariate analyses with Cox's proportional hazard models, we determined the prognostic factors for hematological recovery, defined as neutrophil counts>0.5 and>1.5.10(9)/L, in 91 patients with established life-threatening DIA. RESULTS: Multivariable analysis showed that neutrophil count<0.1.10(9)/L (at diagnosis) and infection profile: severe infections or septic shock, adversely influenced the neutrophil recovery (for the two neutrophil levels). Hematopoietic growth factors were significantly associated with rapid hematological recovery (for the two neutrophil levels). Documented microbial infections and antiplatelet DIA were also associated with rapid hematological recovery (for a neutrophil count>1.5.10(9)/L). CONCLUSION: Our findings demonstrate that in life-threatening DIA, hematological recovery is mainly dependent of the neutrophil level, the type of infections and the utilization of hematopoietic growth factors.

Vitamin B12 (cobalamin) deficiency in elderly patients.

Vitamin B12 or cobalamin deficiency occurs frequently (> 20%) among elderly people, but it is often unrecognized because the clinical manifestations are subtle; they are also potentially serious, particularly from a neuropsychiatric and hematological perspective. Causes of the deficiency include, most frequently, food-cobalamin malabsorption syndrome (> 60% of all cases), pernicious anemia (15%-20% of all cases), insufficient dietary intake and malabsorption. Food-cobalamin malabsorption, which has only recently been identified as a significant cause of cobalamin deficiency among elderly people, is characterized by the inability to release cobalamin from food or a deficiency of intestinal cobalamin transport proteins or both. We review the epidemiology and causes of cobalamin deficiency in elderly people, with an emphasis on food-cobalamin malabsorption syndrome. We also review diagnostic and management strategies for cobalamin deficiency.