View source for Combined hyperlipidemia

{{Refimprove|date=May 2009}}
{{DiseaseDisorder infobox |
  Name        = Combined hyperlipidemia |
  ICD10       = {{ICD10|E|78|4|e|70}} |
  ICD9        = {{ICD9|272.4}} |
}}
In [[medicine]], '''combined hyperlipidemia''' (or -''aemia'') (also known as "Multiple-type hyperlipoproteinemia") is a commonly occurring form of [[hypercholesterolemia]] (elevated [[cholesterol]] levels) characterised by increased [[LDL]] and [[triglyceride]] concentrations, often accompanied by decreased [[High density lipoprotein|HDL]].<ref name="Andrews">{{cite book |author=James, William D.; Berger, Timothy G.; et al. |title=Andrews' Diseases of the Skin: clinical Dermatology |publisher=Saunders Elsevier |location= |year=2006 |pages= |isbn=0-7216-2921-0 |oclc= |doi= |accessdate=}}</ref>{{Rp|534|date=May 2009}} On lipoprotein [[electrophoresis]] (a test now rarely performed) it shows as a  [[hyperlipoproteinemia type II]]B. It is the most common inherited lipid disorder, occurring in approximately one in two hundred persons. In fact, almost one in five individuals who develop [[coronary heart disease]] before the age of sixty will have this disorder.

The elevated [[triglyceride]] levels (>5 [[mmol]]/[[litre|l]]) are generally due to an increase in [[VLDL]] (very low density lipoprotein), a class of [[lipoprotein]] that is prone to cause [[atherosclerosis]].

== Types ==
There are two forms of this [[lipid]] disorder:
* ''Familial combined hyperlipidemia'' (FCH) is the familial occurrence of this disorder, probably caused by [[polymorphism (biology)|polymorphisms]] in molecules and [[enzyme]]s that participate in [[lipoprotein]] metabolism, such as [[ApoCII]] and [[ApoCIII]] and CETP ([[cholesterylester transferring protein]]).
* ''Acquired combined hyperlipidemia'' is extremely common in patients who suffer from other diseases from the [[metabolic syndrome]] ("syndrome X", incorporating [[diabetes mellitus type II]], [[hypertension]], [[central obesity]] and CH). Excessive [[free fatty acid]] production by various tissues leads to increased [[VLDL]] synthesis by the [[liver]]. Initially, most VLDL is converted into [[LDL]] until this mechanism is saturated, after which VLDL levels elevate.

== Treatment ==
Both conditions are treated with [[fibrate]] drugs, which act on the [[peroxisome proliferator-activated receptor]]s (PPARs), specifically PPARα, to decrease free fatty acid production. 

[[Statin]] drugs, especially the synthetic statins ([[atorvastatin]] and [[rosuvastatin]]) can decrease LDL levels by increasing hepatic reuptake of LDL due to increased LDL-receptor expression.

== See also ==
* [[Primary hyperlipoproteinemia]]

== References ==
{{reflist}}

{{Lipidemias}}

[[Category:Lipid disorders]]
[[Category:Cardiology]]
[[Category:Medical conditions related to obesity]]
[[Category:Skin conditions resulting from errors in metabolism]]
[[Category:2Fix]]