Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024523 (malabsorption)
 7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypobetalipoproteinemias (HBL) represent a heterogeneous group of disorders characterized by reduced plasma levels of total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C) and apolipoprotein B (apoB) below the 5th percentile of the distribution in the population. HBL are defined as primary or secondary according to the underlying causes. Primary monogenic HBL are caused by mutations in several known genes (APOB, PCSK9, MTP, SARA2) or mutations in genes not yet identified. Familial hypobetalipoproteinemia (FHBL) is the most frequent monogenic form of HBL with a dominant mode of inheritance. It may be due to loss-of-function mutations in APOB or, less frequently, in PCSK9 genes. The rare recessive forms of primary monogenic HBL are represented by abetalipoproteinemia (ABL) and chylomicron retention disease (CMRD) due to mutations in MTP and SARA2 genes, respectively. The clinical phenotype of heterozygous FHBL is usually mild, being frequently characterized by fatty liver. The clinical phenotype of homozygous FHBL, ABL, and CMRD is usually severe being characterized by intestinal lipid malabsorption and fat-soluble vitamin deficiency. Secondary HBL are due to several nongenetic factors such as diet, drugs, and disease-related conditions. The aim of this review is to discuss the biochemistry, genetics, and clinical spectrum of HBL and to provide a clinical and laboratory diagnostic algorithm.
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PMID:Hypobetalipoproteinemia: genetics, biochemistry, and clinical spectrum. 2187 58

Cobalamin (Cbl, vitamin B12) consists of a corrinoid structure with cobalt in the centre of the molecule. Neither humans nor animals are able to synthesize this vitamin. Foods of animal source are the only natural source of cobalamin in human diet. There are only two enzymatic reactions in mammalian cells that require cobalamin as cofactor. Methylcobolamin is a cofactor for methionine synthase. The enzyme methylmalonyl-CoA-mutase requires adenosylcobalamin as a cofactor. Therefore, serum concentrations of homocysteine (tHcy) and methylmalonic acid (MMA) will increase in cobalamin deficiency. The cobalamin absorption from diet is a complex process that involves different proteins: haptocorrin, intrinsic factor and transcobalamin (TC). Cobalamin that is bound to TC is called holotranscobalamin (holoTC) which is the metabolically active vitamin B12 fraction. HoloTC consists 6 and 20% of total cobalamin whereas 80% of total serum cobalamin is bound to another binding protein, haptocorrin. Cobalamin deficiency is common worldwide. Cobalamin malabsorption is common in elderly subjects which might explain low vitamin status. Subjects who ingest low amount of cobalamin like vegetarians develop vitamin deficiency. No single parameter can be used to diagnose cobalamin deficiency. Total serum cobalamin is neither sensitive nor it is specific for cobalamin deficiency. This might explain why many deficient subjects would be overlooked by utilizing total cobalamin as status marker. Concentration of holotranscobalamin (holoTC) in serum is an earlier marker that becomes decreased before total serum cobalamin. Concentrations of MMA and tHcy increase in blood of cobalamin deficient subjects. Despite limitations of these markers in patients with renal dysfunction, concentrations of MMA and tHcy are useful functional markers of cobalamin status. The combined use of holoTC and MMA assays may better indicate cobalamin status than either of them. Because Cbl deficiency is a risk factor for neurodegenerative diseases an early diagnosis of a low B12 status is required which should be followed by an effective treatment in order to prevent irreversible damages.
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PMID:Cobalamin deficiency. 2211 6

Osteoporosis is the index disease for calcium deficiency, just as rickets/osteomalacia is the index disease for vitamin D deficiency, but there is considerable overlap between them. The common explanation for this overlap is that hypovitaminosis D causes malabsorption of calcium which then causes secondary hyperparathyroidism and is effectively the same thing as calcium deficiency. This paradigm is incorrect. Hypovitaminosis D causes secondary hyperparathyroidism at serum calcidiol levels lower than 60 nmol/L long before it causes malabsorption of calcium because serum calcitriol (which controls calcium absorption) is maintained until serum calcidiol falls below 20 nmol/L. This secondary hyperparathyroidism, probably due to loss of a "calcaemic" action of vitamin D on bone first described in 1957, destroys bone and explains why vitamin D insufficiency is a risk factor for osteoporosis. Vitamin D thus plays a central role in the maintenance of the serum (ionised) calcium, which is more important to the organism than the preservation of the skeleton. Bone is sacrificed when absorbed dietary calcium does not match excretion through the skin, kidneys and bowel which is why calcium deficiency causes osteoporosis in experimental animals and, by implication, in humans.
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PMID:Evolution of the calcium paradigm: the relation between vitamin D, serum calcium and calcium absorption. 2225 68

The folate transport across the epithelial of the intestine, colon, kidney, and liver is essential for folate homeostasis. The relative localization of transporters in membranes is an important determinant for the vectorial flow of substrates across the epithelia. Folate deficiency is a highly prevalent vitamin deficiency in the world, and alcohol ingestion has been the major contributor. It can develop because of folate malabsorption in tissues, increased renal excretion dietary inadequacy, and altered hepatobiliary metabolism. Additionally, folate-mediated one-carbon metabolism is important for various cellular processes, including DNA synthesis and methylation. In this regard, the contribution of alcohol-associated and dietary folate deficiency to methylation patterns is under intense investigation, especially in cancer. The epigenetic events have increasing relevance in the development of strategies for early diagnosis, prevention, and treatment of cancer.
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PMID:Folate malabsorption and its influence on DNA methylation during cancer development. 2365 Sep 43

Heart failure (HF) is the leading cause of morbidity and mortality in industrialized countries, creating a significant burden on both the healthcare system and quality of life. Research efforts continue to explore new pharmaceutical or surgically based approaches to HF management, but the role of nutrition as an adjunct therapy has been largely ignored. Elderly age, anorexia, malabsorption, premature satiety, and disease severity are among the factors identified as contributing to reduced nutrient intakes in patients with HF. These factors suggest that patients with HF are at increased risk of multiple-nutrient deficiencies, including B vitamins. B vitamins may be of particular therapeutic interest because of their key roles as cofactors in energy-producing pathways. Recently, impaired stores of high-energy compounds have been linked with myocardial dysfunction and prognosis in patients with HF. Therefore, deficiencies of B vitamins might contribute to reduced energy stores and disease progression. This review summarizes the existing literature both with respect to the prevalence of B vitamin deficiency as well as evidence from supplementation trials in patients with HF. The findings suggest that most of the literature in this area has focused on thiamin deficiency in patients with HF, whereas other B vitamins remain largely unstudied. Although few sporadic trials suggest a role for B vitamins in the management of HF, none are conclusive. Therefore, there is a need for larger, more robust trials to assist in defining the B vitamin requirements as well as the impact of supplementation on both morbidity and mortality in patients with HF.
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PMID:The role of B vitamins in the management of heart failure. 2251 40

We report a case of fat-soluble vitamin deficiency in a 14-year old boy who had chronic duodenal obstruction. He presented with periodic unexplained bleeding tendency. The laboratory results showed positive fat globules in stool and prolonged prothrombin time. His further investigation revealed low plasma vitamin A and undetectable plasma vitamin E. After parenteral vitamin K and oral vitamin A and E supplement, these abnormalities resolved although he still had absent knee jerk. We propose that fat malabsorption and fat-soluble vitamin deficiency can occur after prolonged duodenal obstruction that induce bacterial overgrowth following by bile acid deconjugation. Despite very few case reports, screening for fat malabsorption and fat-soluble vitamin deficiency might be warranted in patients with chronic small bowel obstruction.
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PMID:Bleeding tendency in an adolescent with chronic small bowel obstruction. 2301 24

Vitamins are organic substances essential to the maintenance of many physiological functions, and necessary for growth. They are subdivided into two groups: the fat soluble vitamins which include vitamins A, D, E and K and the water-soluble vitamins which include Group B vitamins and vitamin C. The recommendations for vitamins intake must be evaluated at regular intervals, and vary according to the different methods used and the different environments assessed. The shortcomings, but equally the measures of prevention must be taken into account. In industrialized countries, provided that the diet is balanced and in the absence of chronic disease, the majority of needs are covered. Vitamin requirements vary depending on age, sex, state of pregnancy, chronic disease or a specific diet. In industrialized countries, chronic alcoholics and malabsorption cases represent groups at risk of vitamin deficiency. Dietary anamnesis remains the best tool to assess needs and nutritional deficiencies. In infants fed exclusively on milk, the required intake is easy to deduce; on the other hand, the needs assessment becomes more difficult with dietary diversification. In industrialized countries, vitamin D should be administered throughout one's life, and vitamin K during the first three months of life for breast-fed new-borns. In developing countries, nutritional status is precarious and supplementation needs to be adapted accordingly.
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PMID:[Vitamins in pediatrics]. 2309 40

Vitamins are micronutrient chemical compounds that cannot be synthesized by an organism but are essential for human metabolism and life. They act as required intermediaries, cofactors or coenzymes in many of the reactions of normal metabolism. In addition, anti-inflammatory effects have been reported for specific vitamins. In inflammatory bowel disease (IBD), vitamin deficiency is often due to malnutrition (due to a decreased food intake) or malabsorption (due to inflamed, malfunctioning mucosa and diarrhea) which results in anemia. Vitamin B(12) and folic acid supplementation may be necessary in IBD patients, especially those with Crohn's disease (CD) with either inflammation of the terminal ileum or after resection of the terminal ileum. It is also recommended during therapy with sulfasalazine as this compound inhibits the absorption of vitamin B(12). Patients with high or continuous inflammatory CD activity and frequent therapy with steroids have an increased risk of low bone mineral density and vitamin D deficiency. These should be monitored regularly and vitamin D should be supplemented. In a recent trial, a trend towards a reduced risk of relapses in CD patients treated with vitamin D was reported. Only limited studies and case reports exist on other vitamin deficiencies, e.g. vitamins A, B(1), B(2), niacin, B(6), C, E and K, found in IBD patients. These are summarized in this review. Regular nutritional monitoring in IBD patients is warranted and requires the special attention of treating physicians and dieticians.
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PMID:Intestinal absorption and vitamin levels: is a new focus needed? 2329 95

Endocrine diseases that may cause hypercalcemia and hypocalcemia include hyperparathyroidism, hypoparathyroidism, thyroid disorders, hyperadrenocorticism, hypoadrenocorticism, and less commonly pheochromocytoma and multiple endocrine neoplasias. The differential diagnosis of hypercalcemia may include malignancy (lymphoma, anal sac carcinoma, and squamous cell carcinoma), hyperparathyroidism, vitamin D intoxication, chronic renal disease, hypoadrenocorticism, granulomatous disorders, osteolysis, or spurious causes. Hypocalcemia may be caused by puerperal tetany, pancreatitis, intestinal malabsorption, ethlyene glycol intoxication, acute renal failure, hypopararthyroidism, hypovitaminosis D, hypomagnesemia, and low albumin. This article focuses on the endocrine causes of calcium imbalance and provides diagnostic and therapeutic guidelines for identifying the cause of hypercalcemia and hypocalcemia in veterinary patients.
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PMID:Endocrine causes of calcium disorders. 2341 81

Phrynoderma is a type of follicular hyperkeratosis located primarily on the extensor surfaces of the extremities. It is most commonly seen in Africa and Southeast Asia, where it is correlated with malnutrition; however, it is rare in developed countries, where it is often the result of malabsorption secondary to pancreatic insufficiency, colectomy, chronic giardiasis, and bariatric surgery. Here, we report a case of a 51-year-old white male patient, who presented to our Institute with a 1-year history of diffuse, reddish-brown asymptomatic papules associated with follicular nodules. In association with cutaneous symptomatology, the patient complained of also having night blindness. The patient, 4 years before, underwent a bariatric surgical treatment, which included a biliopancreatic diversion. Histologic examination of skin biopsy revealed hyperkeratosis and irregular acanthosis of the epidermis in association with dilated follicular infundibulum filled with keratinous material, whereas the laboratory investigations showed hypovitaminosis A. Based on the patient's history and cutaneous biopsy, a final diagnosis of phrynoderma was made. The steady increase of obesity in developed countries results in a relative increase in bariatric surgery. This must involve a multidisciplinary team to manage nutrition deficiencies and prevent possibly important complications, as mentioned in this report.
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PMID:Biliopancreatic diversion: when a cure becomes a disease. 2371 82


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