1/13. Acquired lipoprotein lipase deficiency associated with chronic urticaria. A new etiology for type I hyperlipoproteinemia.Type I hyperlipoproteinemia (type I HLP) is a rare disorder of lipid metabolism characterized by fasting chylomicronemia and reduced postheparin plasma lipoprotein lipase (LPL) activity. Most cases of type I HLP are due to genetic defects in the LPL gene or in its activator, the apolipoprotein CII gene. Several cases of acquired type I HLP have also been described in the course of autoimmune diseases due to the presence of circulating inhibitors of LPL. Here we report a case of type I HLP due to a transient defect of LPL activity during puberty associated with chronic idiopathic urticaria (CIU). The absence of any circulating LPL inhibitor in plasma during the disease was demonstrated. The LPL genotype showed that the patient was heterozygous for the D9N variant. This mutation, previously described, can explain only minor defects in the LPL activity. The presence of HLP just after the onset of CIU, and the elevation of the LPL activity with remission of the HLP when the patient recovered from CIU, indicate that type I HLP was caused by CIU. In summary, we report a new etiology for type I HLP - a transient decrease in LPL activity associated with CIU and with absence of circulating inhibitors. This is the first description of this association, which suggests a new mechanism for type I HLP.- - - - - - - - - - ranking = 1keywords = hyperlipoproteinemia (Clic here for more details about this article) |
2/13. Type I hyperlipoproteinemia due to a novel loss of function mutation of lipoprotein lipase, Cys(239)-->Trp, associated with recurrent severe pancreatitis.lipoprotein lipase (LPL) is the major enzyme responsible for the hydrolysis of triglyceride-rich lipoproteins in plasma. The purpose of this study was to examine the molecular pathogenesis of type I hyperlipoproteinemia in a patient suffering from recurrent severe pancreatitis. Apolipoprotein (apo) CII concentration was normal as well as apo CII-activated LPL in an in vitro assay. In postheparin plasma neither LPL mass nor activity was detectable, whereas hepatic lipase activity was normal. Direct sequencing of all 10 exons of the LPL gene revealed that the patient was homozygous for a hitherto unknown mutation in exon 6, Cys(239)-->Trp. The mutation prevents the formation of the second disulfide bridge of LPL, which is an essential part of the lid covering the catalytic center. Consequently, misfolded LPL is rapidly degraded within the cells, causing the absence of LPL immunoreactive protein in the plasma of this patient. In conclusion, we have identified a novel loss of function mutation in the LPL gene (Cys(239)-->Trp) of a patient with type I hyperlipoproteinemia suffering from severe recurrent pancreatitis. After initiation of heparin therapy (10,000 U/day sc), the patient experienced no more episodes of pancreatitis, although heparin therapy did not affect serum triglyceride levels.- - - - - - - - - - ranking = 1.2keywords = hyperlipoproteinemia (Clic here for more details about this article) |
3/13. A family-based study of hyperinsulinemia and hypertriglyceridemia in heterozygous lipoprotein lipase deficiency.CASE REPORT: A case is presented of predisposing a patient's father with obligate heterozygous lipoprotein lipase (LPL) deficiency to mild hypertriglyceridemia in Japanese I-family members (n=8) with patient DI, who was a compound heterozygote for a novel missense mutation of G154V (GG(716)C-->GTC/Gly(154) Val) in exon 5 and a novel splice mutation (Int8/5'-dss/t( 2)c; a T-to-C transition in the invariant GT at position 2 of the 5' donor splice site (dss)) in intron 8 of the LPL gene. RESULTS: The patient's father and paternal grandmother were heterozygotes for the Int8/5'-dss/t( 2)c allele, while the patient's mother and maternal grandmother were heterozygotes for the G154V allele. These four heterozygous carriers with one defective LPL allele showed 45-57% of the mean LPL activity and mass in the post-heparin plasma (PHP) observed in normal individuals. Among the four heterozygous carriers, the patient's father, who was <40 years old, nonobese and hyperinsulinemia, manifested mild hypertriglyceridemia (type IV hyperlipoproteinemia). The remaining three healthy heterozygous carriers (two were >40 years old and the other was <40 years old) were all normolipidemic state. CONCLUSION: In this family, hyperinsulinemia as a marker of insulin resistance may be a strong determinant of hypertriglyceridemia in the carrier with heterozygous LPL deficiency.- - - - - - - - - - ranking = 0.2keywords = hyperlipoproteinemia (Clic here for more details about this article) |
4/13. Type I hyperlipoproteinemia caused by lipoprotein lipase defect in lipid-interface recognition was relieved by administration of medium-chain triglyceride.We have previously reported lipoprotein lipase with a defect of lipid-interface recognition in a patient with type I hyperlipoproteinemia. In this patient, lipoprotein lipase from post-heparin plasma (PHP) hydrolyzed monomeric substrate tributyrin, but scarcely hydrolyzed triolein emulsified with Triton X-100 and that in very-low-density lipoproteins ([VLDL] d < 1.006 g/mL), and did not bind to VLDL. The triglyceride (TG) level of this patient did not decrease to less than 1,000 mg/dL with a low-fat diet (1,400 kcal containing 10 g fat/d). When the patient took 30 g medium-chain TG (MCT) in addition to the 1,400-kcal diet, her serum TG level decreased to 250 mg/dL and her clinical signs improved. The low clearance rate of serum TG with heparin injection improved after intake of MCT. Caproic acid levels were maintained at 1.4% and 2.6% in chylomicrons and VLDL after MCT intake, respectively. The patient's lipoprotein lipase hydrolyzed triolein emulsified with 2% tricaprin at the same rate as that of control lipoprotein lipase. The patient's lipoprotein lipase-catalyzed hydrolyzing rate of triolein in chylomicrons obtained after MCT administration was also enhanced up to 70% of that of control lipoprotein lipase. These findings suggest that hypertriglyceridemia caused by lipoprotein lipase with a defect in lipid-interface recognition could be relieved with the administration of medium-chain TG, and that one of the mechanisms of this effect might be a modification of TG-rich lipoproteins by MCT.- - - - - - - - - - ranking = 1keywords = hyperlipoproteinemia (Clic here for more details about this article) |
5/13. hyperlipoproteinemia type i in a patient with active lipoprotein lipase in adipose tissue and indications of defective transport of the enzyme.This paper presents a case of typical hyperlipoproteinemia type i in a young woman. Her serum triglycerides varied between 2 and 90 mmol/l and she had substantial amounts of apolipoprotein b-48 in fasting plasma. She had no detectable lipoprotein lipase (LPL) activity in post-heparin plasma (less than 0.2 percent of normal). Southern blot analysis suggested no major defect in her LPL gene and Northern blot analysis of adipose tissue rna showed normal-sized LPL-mRNA. A 2-h [35S]methionine incorporation experiment with adipose tissue pieces in vitro showed that she produced normal-sized LPL and had LPL catalytic activity in the tissue. The amounts were, however, only 5-10% of control. No detectable LPL radioactivity or catalytic activity was released from patient tissue even in the presence of heparin in the incubations. Immunofluorescent staining of adipose tissue biopsies from the patient showed LPL immunoreactivity only in adipocytes and little or none within the capillaries. Treatment of immunoprecipitated labeled LPL with endoglycosidase H showed that the oligosaccharide chains on her enzyme were of the high-mannose type and not processed as in controls. Taken together the data suggest that the patient synthesizes a relatively normal LPL protein which is core-glycosylated and folded into active enzyme as in normal subjects, but is not effectively transported via the Golgi to the cell surface.- - - - - - - - - - ranking = 0.21481140729837keywords = hyperlipoproteinemia, hyperlipoproteinemia type (Clic here for more details about this article) |
6/13. Familial type I hyperlipoproteinemia caused by apolipoprotein c-ii deficiency.A study was made on the clinical and biochemical features of siblings of patients with hyperchylomicronemia and its inherited relationship. It was not a case of the classical type of familial LPL deficiency, but of familial apolipoprotein c-ii deficiency. The first patient with apolipoprotein c-ii deficiency was reported by Breckenridge et al. and our patients provide the basis for the second report of this new disease. Our observations in this study strongly suggest that familial apolipoprotein c-ii deficiency is transmitted by an autosomal recessive mode of inheritance and heterozygotes of this disorder have no abnormalities of plasma lipid and lipoproteins in spite of the reduced plasma apolipoprotein c-ii.- - - - - - - - - - ranking = 0.8keywords = hyperlipoproteinemia (Clic here for more details about this article) |
7/13. A case of association between type I hyperlipoproteinemia and systemic lupus erythematosus (SLE). Effects of steroid treatment.The case of a girl aged 19 yr with hypertriglyceridemia and systemic lupus erythematosus (SLE) is described. The girl had been admitted to a Lipid Outpatient Clinic in 1981 and diagnosed as having a Type I hyperlipidemia pattern. In November 1984 the patient acutely developed a SLE syndrome. Steroid treatment led to a dramatic fall of serum triglycerides from a starting value of 2100 mg/dl to 95 mg/dl. The role of steroids in completely correcting genetically deficient lipoprotein lipase Activity (LLA) is discussed.- - - - - - - - - - ranking = 0.8keywords = hyperlipoproteinemia (Clic here for more details about this article) |
8/13. An incomplete form of familial lipoprotein lipase deficiency presenting with type I hyperlipoproteinemia.The author reports the case of a patient with an incomplete form of familial lipoprotein lipase deficiency associated with type I hyperlipoproteinemia manifesting an autosomal recessive pattern of inheritance. The patient presented with hepatosplenomegaly, abdominal pain, and fasting chylomicronemia. A Western diet elicited a steep increase in plasma triglyceride concentration and the appearance of floating chylomicrons over a clear infranatant in fasting plasma. Postheparin lipoprotein lipase activity was moderately reduced to 38% of control values. adipose tissue lipoprotein lipase activity was 10% of normal, whereas his muscle enzyme activity was within the reference range. Two-dimensional electrophoresis of plasma apolipoproteins revealed the presence of normal activator (apolipoprotein c-ii). These results confirm the importance of the adipose tissue enzyme for the clearance of diet-derived plasma triglycerides.- - - - - - - - - - ranking = 1keywords = hyperlipoproteinemia (Clic here for more details about this article) |
9/13. milk and plasma lipid composition in a lactating patient with type I hyperlipoproteinemia.This report describes studies on the plasma and milk lipid composition of a patient with primary Type I hyperlipoproteinemia who had been followed through her second pregnancy. Post-partum she lactated, supplying milk for assay. It was abnormal in the low content of its total lipid and in the bizarre composition of its fatty acids. The proportion of long chain fatty acids was unusually low, and that of medium chain fatty acids unusually high. Furthermore, the fatty acids of the patient's milk differed greatly from those of her plasma triglycerides. This was in marked contrast to normal nursing mothers' milk, in which the fatty acid composition is comparable to that of plasma triglycerides. The patient's milk fatty acids were shorter in chain length and deficient in essential fatty acids. During the time of lactation, the patient remained hyperlipidemic and her post-heparin plasma had no lipolytic activity. These data and the differences between the plasma and milk fatty acids suggested that in the patient the circulating triglyceride fatty acids did not enter the mammary gland. Without preformed fatty acids entering it from plasma or adipose tissue, the lactating breast apparently synthesized fatty acids de novo. These newly synthesized fatty acids were of medium, rather than long chain length. This accounted for the abundance of medium chain length triglycerides in the patient's milk. The studies suggested that the deficit of lipoprotein lipase in Type I hyperlipoproteinemia extended to the mammary gland.- - - - - - - - - - ranking = 1.2keywords = hyperlipoproteinemia (Clic here for more details about this article) |
10/13. Postheparin plasma lipoprotein lipase activity in heterozygotes of familial lipoprotein lipase deficiency.serum lipoprotein pattern, apoproteins and two postheparin triglyceride lipases were analyzed in a patient with familial lipoprotein lipase (LPL) deficiency and her family. serum of the patient showed extreme hyperchylomicronemia and her postheparin plasma LPL activity was distinctly decreased. None of heterozygotes had any type of hyperlipoproteinemia. The mother and brother of the patient had moderately decreased LPL activity. There were no consistent changes in hepatic triglyceride lipase (H-TGL) activity among heterozygotes. These results suggest that assay of LPL may be helpful for detection of heterozygotes in familial LPL deficiency.- - - - - - - - - - ranking = 0.2keywords = hyperlipoproteinemia (Clic here for more details about this article) |
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