Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

A well-defined degenerative neurological condition has been associated with cholestatic liver disease in children. This syndrome, heralded by gait and limb ataxia, areflexia, and proprioceptive and vibratory sensory loss, has also been observed in abetalipoproteinemia (Bassen-Kornzweig syndrome), cystic fibrosis, and intestinal malabsorption states. A significant body of evidence suggests that vitamin E (alpha-tocopherol) deficiency is in large part responsible for this condition. In this article, a patient manifesting this syndrome is reported, and the current status of the vitamin E deficiency state is reviewed.
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PMID:Neurologic complications of vitamin E deficiency: case report and review of the literature. 391 52

We describe a child, the issue of phenotypically normal parents, who had fat malabsorption, both intestinal and hepatic steatosis, and serum cholesterol and triglyceride concentrations of 38 and 63 mg/dl, respectively. Lipoprotein electrophoresis, Ouchterlony double diffusion, and electron microscopy demonstrated that normal low density lipoproteins (LDL: 1.006 less than rho less than 1.063 g/ml) were absent. Lipoprotein particles in the rho less than 1.006-g/ml fraction were triglyceride rich, very large (93.2 +/- 35.1 nm), and contained the B-48 but not the B-100 apoprotein; both species of apolipoprotein (apo) B were found in the parents' lipoproteins. These chylomicrons and chylomicron remnants were present even in the patient's fasting plasma, which suggested prolonged dietary fat absorption. Plasma levels of high density lipoprotein lipids and proteins were low, and the phosphatidylcholine/sphingomyelin ratio was reduced as in typical abetalipoproteinemia. The monosialylated form of apo C-III was not identified on polyacrylamide gel electrophoresis, which suggested that this protein was elaborated only with very low density lipoproteins (VLDL). A radioimmunoassay for apo B employing a polyclonal antisera to plasma LDL gave apparent plasma apo B levels of 0.6, 66, and 57 mg/dl in the patient and his father and mother, respectively. The displacement curve generated by the parents' VLDL and LDL did not did not differ from control lipoproteins. The patient's chylomicron-chylomicron remnant fraction displaced normal LDL over the entire radioimmunoassay range, but the efficiency of displacement was strikingly less than with B-100 containing lipoproteins. If the patient's B-48 protein is not qualitatively abnormal, these results confirm very limited immunochemical cross-reactivity between at least one major epitope on B-100 and the epitopes expressed on B-48. The apo B defect in this patient appears to be recessive. It abolishes B-100 production and may additionally limit the formation of B-48.
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PMID:Apolipoprotein B-100 deficiency. Intestinal steatosis despite apolipoprotein B-48 synthesis. 403 Oct 57

DETAILED STUDIES OF THE HIGH DENSITY LIPOPROTEINS FROM THREE PATIENTS WITH ABETALIPOPROTEINEMIA HAVE REVEALED THE FOLLOWING PRINCIPAL ABNORMALITIES: 1) High density lipoprotein 3 (HDL3) is reduced in both absolute and relative concentration, although HDL2 is present in normal amounts. 2) The phospholipid distribution of both HDL fractions is abnormal, with low concentrations of lecithin and an increased percentage (though normal absolute quantity) of sphingomyelin. 3) In both HDL fractions, lecithin contains less linoleate and more oleate than normal. The cholesteryl esters are also low in linoleic acid, and the sphingomyelin is high in nervonic acid. Dietary intake influences the linoleic acid concentration within 2 weeks, and perhaps sooner, but the elevated sphingomyelin nervonic acid is little affected by up to 6 months of corn oil supplementation. Qualitatively similar changes in fatty acid composition, but not phospholipid distribution, are also found in other malabsorption states. The available evidence suggests that the abnormally low levels of HDL3 and the deranged phospholipid distribution are more specific for abetalipoproteinemia than the fatty acid abnormalities. However, the absence of these abnormalities in obligate heterozygous subjects makes their relationship to the primary defect of abetalipoproteinemia difficult to assess.
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PMID:Abnormalities of high density lipoproteins in abetalipoproteinemia. 602 78

A 27-year-old woman who had undergone extensive small bowel resection at age 14 months developed kyphoscoliosis, ocular palsies, constricted visual fields, retinitis pigmentosa, progressive ataxia, muscular weakness, nearly absent vibration and impaired position sense, areflexia, extensor plantar responses, and macrocytic anemia. Her condition closely resembled Bassen-Kornzweig disease, but lipoprotein electrophoresis was normal. Mild fat malabsorption, lactic acidosis, and severe deficiency of vitamins A and E and carotene were documented. Serum B12 and folic acid levels were normal. During vitamin A and E therapy sufficient to elevate serum levels to the normal range, there was improvement of visual fields and visual acuity in dim light, lactic acidosis, and red cell volume. Progression of symptoms was halted during vitamin replacement therapy, and her gait improved. This syndrome is the human counterpart to vitamin E deficiency in experimental animals.
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PMID:Small bowel resection with vitamin E deficiency and progressive spinocerebellar syndrome. 654 Mar 84

The clinical and pathophysiological features of a case of abetalipoproteinemia in a 34-year-old patient are described. This patient is the first case reported in Japan. The patient was diagnosed as abetalipoproteinemia by confirming the Apo-B deficiency in the patient's serum and the slightly high cholesterol level in his mother's and borderline normal level in his father's. The patient had remarkably low lipid levels, acanthocytosis, and lipid malabsorption. An unusual feature of this case was that the patient had no neuromuscular or ocular manifestations. This was possibly related to his normal plasma vitamin A and E levels.
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PMID:A case report of abetalipoproteinemia (Bassen-Kornzweig syndrome)--the first case in Japan. 662 Jul 11

A case of oxalate lithiasis associated with Abetalipoproteinemia is reported. The excessive absorption of dietary oxalate in this patient with fat malabsorption occurs because unabsorbed fatty acids in the bowel lumen combine with calcium ions which would otherwise impair oxalate absorption by forming insoluble calcium oxalate crystals. The medical management include dietary fat restriction and supplements of the fat soluble vitamins A, E and K. The prognostic is poor particularly in the neurological and retinal component of this disease.
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PMID:[Oxalate lithiasis associated bith abetalipoproteinemia. Report of a case]. 667 Dec 65

The concept that an absence of apoprotein B in plasma may result in increased cholesterol biosynthesis was investigated by sterol balance techniques in 2 male patients with abetalipoproteinemia, one an adult, the other a child. Total body synthesis of cholesterol in both the adult patient (19.3 +/- 3.8 mg/kg/day vs. 10.8 +/- 0.9 mg/kg/day in controls) and the child with abetalipoproteinemia (34.9 mg/kg/day vs. 14.5 +/- 3.8 mg/kg/day in control children) was significantly higher than in controls whereas bile acid synthesis was similar in both groups. Absorption of orally administered [1,2-3H]cholesterol was lower in the abetalipoproteinemic subjects than the controls and subsequent labeling of plasma cholesterol in the former patients was minimal (less than 3% of controls). The mechanisms for the increased sterol synthesis in abetalipoproteinemia may relate to the absence of chylomicrons and low density lipoproteins in plasma, but the magnitude of the increase can be largely explained on the basis of enhanced sterol losses that occur secondary to malabsorption of biliary cholesterol.
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PMID:Lipid metabolism in abetalipoproteinemia: a study of cholesterol absorption and sterol balance in two patients. 735 37

Abetalipoproteinemia is an inherited disorder of lipoprotein metabolism. Affected individuals produce virtually no circulating apolipoprotein B-containing lipoproteins (chylomicrons, very low density lipoprotein, low density lipoprotein and lipoprotein (a)). Malabsorption of the antioxidant vitamin E occurs, leading to spinocerebellar and retinal degeneration. Biochemical and genetic studies show that abetalipoproteinemia is not a defect of lipid biosynthesis or of the apolipoprotein B gene. Instead a microsomal triglyceride transfer protein, which exists as a complex with protein disulphide isomerase in the endoplasmic reticulum, has been implicated. We have cloned and sequenced the human cDNA encoding microsomal triglyceride transfer protein. The predicted amino acid sequence shows extensive homology to vitellogenin, the precursor of the lipovitellin complex, which has been shown by X-ray crystallography to contain a large lipid storage cavity. Microsomal triglyceride transfer protein is expressed in ovary, testis and kidney, in addition to liver and small intestine. A homozygous mutation that disrupts splicing has been identified in affected siblings with classical abetalipoproteinemia. These results elucidate a key process in the packaging of apolipoprotein B with lipid, and should increase our understanding of the processes regulating the production of atherogenic lipoproteins.
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PMID:Abetalipoproteinemia is caused by defects of the gene encoding the 97 kDa subunit of a microsomal triglyceride transfer protein. 811 81

Abetalipoproteinemia is a recessive genetic disorder of unknown origin, which is characterized by absence of circulating apo-B-containing lipoproteins, malabsorption of intestinal fat, and degenerative neurological and retinal lesions. In this study, four families were analysed for genetic linkage between the abetalipoproteinemia phenotype and the apo-B genotype determined from polymorphisms of XbaI, MsPI, EcoRI and PvuII restriction sites and that of the 3'-minisatellite of the apo-B gene. The results definitively exclude mutation of the apo-B gene as a causal factor of abetalipoproteinemia in three families. Consanguinity of the parents in the fourth family made genotyping less conclusive.
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PMID:Genetic exclusion of apo-B gene in recessive abetalipoproteinemia. 842 64

The fifth- and ninety-fifth-percentile concentrations of low-density lipoprotein (LDL) cholesterol in most Western populations are approximately 90 and 200 mg/dl, respectively. Persons with LDL cholesterol levels equal to or less than the fifth percentile are defined as having hypobetalipoproteinemia. Epidemiologic studies show that such individuals have lower-than-average risk for atherosclerotic cardiovascular disease but higher risk for a variety of cancers, pulmonary, and gastrointestinal diseases than persons with higher levels of cholesterol. The reasons for this are not known, nor are the causes of most cases of hypobetalipoproteinemia. However, in some well-studied kindreds the hypobetalipoproteinemia phenotype is inherited as an autosomal dominant trait. Heterozygotes in such kindreds are usually healthy and have no difficulty absorbing dietary fat. In most kindreds, the molecular variants responsible for the hypobetalipoproteinemia are unknown, but a subset of kindreds have strong genetic linkages between the low-cholesterol phenotype and truncation-producing mutations of the apolipoprotein (apo) B-100 gene. The truncations of apoB are named according to a centile nomenclature. The full-length 4536-amino acid protein is called apoB-100, and the 25 truncations identified to date have been named apoB-2 to apoB-89. The mutations introduce premature termination codons resulting from frameshift-producing base additions or deletions. The mutations produce slowed rates of secretion of the truncated apoBs relative to the apoB-100s present in the heterozygotes. In addition, the apoB-100 molecules of the heterozygotes are also secreted at rates slower than those observed in closely matched normolipidemic controls. These physiologic results account for the hypobetalipoproteinemia of these subjects. The response of the plasma lipoproteins of heterozygotes to the manipulation of various dietary components remains to be determined. Additional low-cholesterol syndromes are autosomal recessive forms of hypobetalipoproteinemia, chylomicron retention disease, and abetalipoproteinemia. The molecular causes of the first two are unknown. Abetalipoproteinemia is an autosomal recessive condition resulting from mutations of the microsomal triglyceride transfer protein. All three conditions are characterized by vanishingly small concentrations of LDL, dietary fat malabsorption, and failure to thrive in infancy.
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PMID:The hypobetalipoproteinemias. 852 19


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