Sunday, October 28, 2012

Hyperlipoproteinemia



 A) Primary Hyperlipoproteinemia
TYPECLASSIFICATIONBIOCHEMICAL DEFECTINHERITANCEPLASMA LIPIDS AND LIPOPROTEINSCLINICAL FEATURES
I.Familial lipoprotein lipase deficiency(Hyperchylomicronemia)Deficiency of lipoprotein lipase. A variant of this diseases can be produced by deficiency of apo CII.Autosomal recessiveTG↑, cholesterol may also be increased, Chylomicrons ++, VLDL↑, HDL and LDL ↓.Refrigeration test confirms the presence of chylomicrons in serumPresent in early childhood, Eruptive xanthomas, Recurrent abdominal pain, no premature cardiovascular disease
II.Familial Hypercholesterolemia(FHC)No enzyme deficiency but there is increased synthesis of apo- B protein and there is impaired degradation of LDLAutosomal dominantLDL ↑, total cholesterol ↑, VLDL  and TG are also raisedXanthomas, corneal arcus, increased risk of premature Cardiovascular disease.
III.Familial Dysbeta lipoproteinemiaAlso called- Broad beta disease , ‘Remnant removal disease”Increase concentration of apo-E, increased synthesis of Apo B, conversion of normal VLDL to IDL and its degradation without conversion to LDL. Defect in Remnant removal.Autosomal dominantLDL↑, VLDL↑, actual rise in IDL which appears as Broad beta band on electrophoresis. TG↑, cholesterol may also be increased.Tuberous and Palmar xanthomas, increased risk of premature Cardiovascular disease and peripheral vascular disease.
IV.Familial Hypertriglyceridemia(FHTG)Increased synthesis  and decreased catabolism of endogenous TGsAutosomal dominantHyper pre beta lipoproteinemia VLDL↑, TG and cholesterol also↑, α and β-lipoproteins are subnormal (HDL↓ and LDL↓). There is associated impaired Glucose TolerancePresents in early childhood, and is commonly associated with CHD, Diabetes Mellitus, Alcoholism and  obesity
V.Combined HyperlipidemiaUsually secondary to other disorders like obesity, excessive alcohol intake, renal failure and pancreatitis etc. Exact biochemical defect is not knownAutosomal dominantComplex lipoprotein pattern, Increase in both chylomicrons and pre β-lipoproteins (VLDL), TG and cholesterol also↑↑, α and β-lipoproteins are subnormal (HDL↓ and LDL↓).Xanthomas are frequently present impaired glucose tolerance, frequently found associated with CHD, Diabetes Mellitus, Alcoholism and  obesity
B) Secondary Hyperlipoproteinemia
S. .NoDiseaseSerum total CholesterolSerum triglycerides
1.Diabetes MellitusIncreasedIncreased
2.Nephrotic syndromeIncreasedIncreased
3.HypothyroidismIncreasedIncreased
4.Biliary obstructionIncreasedNormal
5.PregnancyIncreasedNormal
6.AlcoholismNormalIncreased
7.Oral contraceptivesNormal
Hypolipoproteinemia
DiseaseBiochemical defectInheritanceLaboratory findingsClinical manifestations
Familial HypobetalipoproteinemiaInability to synthesize ApoB100 and Apo-B48Autosomal dominantLDL between 10 to 50 % of normal, Cholesterol low but Triglycerides and Chylomicrons normal.Mostly asymptomatic, but there is decreased risk of CHD
AbetalipoproteinemiaNo synthesis or secretion  of Apo B containing lipoproteinsRare inherited diseaseVLDL↓, LDL↓↓, B-100↓, B-48↓, decrease in TG and a marked ↓in Serum total cholesterol, prolonged prothrombin time.Malabsorption, mental and physical retardation, acanthocytosis, Atypical retinitis pigmentosa, fatty infiltration of intestinal mucosal cells and liver.
HypoalphalipoproteinemiaNot knownAutosomal dominantHDL↓, Cholesterol and TGs normalIncreased risk of CHD
Familial Alpha lipoprotein deficiency(Tangier’s disease)Deficiency of alpha lipoprotein. Cholesteryl esters are deposited in the reticulo endothelial system, but functions of major organs are not affectedAutosomal recessiveLow or absent HDL, Lack of Alpha band on electrophoresis.Orange yellow tonsils and adenoids, muscle weakness, atrophy, recurrent peripheral neuropathies and depressed tendon reflexes. The pharyngeal and rectal mucosa is also orange colored.(The orange color is due to deposition of cholesteryl esters.) There is increased predisposition to Atherosclerosis.




------------------------------------------ Best Wishes: Dr.Ehab Aboueladab, Tel:01007834123 Email:ehab10f@gmail.com,ehababoueladab@yahoo.com ------------------------------------------
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