For those at high risk, a combination of lifestyle modification and statins has been shown to decrease mortality.

Screening among family members of people with known FH is cost-effective. Other strategies such as universal screening at the age of 16 were suggested in 2001. The latter approach may however be less cost-effective in the short term. Screening at an age lower than 16 was thought likely to lead to an unacceptably high rate of false positives.

A 2007 meta-analysis found that "the proposed strategy of screening children and parents for familial hypercholesterolaemia could have considerable impact in preventing the medical consequences of this disorder in two generations simultaneously." "The use of total cholesterol alone may best discriminate between people with and without FH between the ages of 1 to 9 years."

Screening of toddlers has been suggested, and results of a trial on 10,000 one-year-olds were published in 2016. Work was needed to find whether screening was cost-effective, and acceptable to families.

Diet has an effect on blood cholesterol, but the size of this effect varies between individuals. Moreover, when dietary cholesterol intake goes down, production (principally by the liver) typically increases, so that blood cholesterol changes can be modest or even elevated. This compensatory response may explain hypercholesterolemia in anorexia. A 2016 review found tentative evidence that dietary cholesterol is associated with higher blood cholesterol. Trans fats have been shown to reduce levels of HDL while increasing levels of LDL. LDL and total cholesterol also increases by very high fructose intake.

These unclassified forms are extremely rare:

- Hyperalphalipoproteinemia

- Polygenic hypercholesterolemia

Hyperlipoproteinemia type V, also known as mixed hyperlipoproteinemia familial or mixed hyperlipidemia, is very similar to type I, but with high VLDL in addition to chylomicrons.

It is also associated with glucose intolerance and hyperuricemia.

In medicine, combined hyperlipidemia (or -aemia) (also known as "multiple-type hyperlipoproteinemia") is a commonly occurring form of hypercholesterolemia (elevated cholesterol levels) characterized by increased LDL and triglyceride concentrations, often accompanied by decreased HDL. On lipoprotein electrophoresis (a test now rarely performed) it shows as a hyperlipoproteinemia type IIB. It is the most common inherited lipid disorder, occurring in about one in 200 persons. In fact, almost one in five individuals who develop coronary heart disease before the age of 60 has this disorder.

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

Types

1. Familial combined hyperlipidemia (FCH) is the familial occurrence of this disorder, probably caused by decreased LDL receptor and increased ApoB.

2. FCH 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.

Both conditions are treated with fibrate drugs, which act on the peroxisome proliferator-activated receptors (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.

In 2016 the United States Preventive Services Task Force concluded that testing the general population under the age of 40 without symptoms is of unclear benefit.

Familial hypercholesterolemia (FH) is a genetic disorder characterized by high cholesterol levels, specifically very high levels of low-density lipoprotein (LDL, "bad cholesterol"), in the blood and early cardiovascular disease. Since individuals with FH underlying body biochemistry is slightly different, their high cholesterol levels are less responsive to the kinds of cholesterol control methods which are usually more effective in people without FH (such as dietary modification and statin tablets). Nevertheless, treatment (including higher statin doses) is usually effective.

FH is classified as a type 2 familial dyslipidemia. There are five types of familial dyslipidemia (not including subtypes), and each are classified from both the altered lipid profile and by the genetic abnormality. For example, high LDL (often due to LDL receptor defect) is type 2. Others include defects in chylomicron metabolism, triglyceride metabolism, and metabolism of other cholesterol-containing particles, such as VLDL and IDL.

About 1 in 300 to 500 people have mutations in the "LDLR" gene that encodes the LDL receptor protein, which normally removes LDL from the circulation, or apolipoprotein B (ApoB), which is the part of LDL that binds with the receptor; mutations in other genes are rare. People who have one abnormal copy (are heterozygous) of the "LDLR" gene may develop cardiovascular disease prematurely at the age of 30 to 40. Having two abnormal copies (being "homozygous") may cause severe cardiovascular disease in childhood. Heterozygous FH is a common genetic disorder, inherited in an autosomal dominant pattern, occurring in 1:500 people in most countries; homozygous FH is much rarer, occurring in 1 in a million births.

Heterozygous FH is normally treated with statins, bile acid sequestrants, or other lipid lowering agents that lower cholesterol levels. New cases are generally offered genetic counseling. Homozygous FH often does not respond to medical therapy and may require other treatments, including LDL apheresis (removal of LDL in a method similar to dialysis) and occasionally liver transplantation.

Hypertriglyceridemia denotes high ("hyper-") blood levels ("-emia") of triglycerides, the most abundant fatty molecule in most organisms. Elevated levels of triglycerides are associated with atherosclerosis, even in the absence of hypercholesterolemia (high cholesterol levels), and predispose to cardiovascular disease. Very high triglyceride levels also increase the risk of acute pancreatitis. Hypertriglyceridemia itself is usually symptomless, although high levels may be associated with skin lesions known as "xanthomas".

The diagnosis is made on blood tests, often performed as part of screening. Once diagnosed, other blood tests are usually required to determine whether the raised triglyceride level is caused by other underlying disorders ("secondary hypertriglyceridemia") or whether no such underlying cause exists ("primary hypertriglyceridaemia"). There is a hereditary predisposition to both primary and secondary hypertriglyceridemia.

Weight loss and dietary modification may improve hypertriglyceridemia. The decision to treat hypertriglyceridemia with medication depends on the levels and on the presence of other risk factors for cardiovascular disease. Very high levels that would increase the risk of pancreatitis is treated with a drug from the fibrate class. Niacin and omega-3 fatty acids as well as drugs from the statin class may be used in conjunction, with statins being the main drug treatment for moderate hypertriglyceridemia where reduction of cardiovascular risk is required.

Both conditions are treated with fibrate drugs, which act on the peroxisome proliferator-activated receptors (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.

The two forms of this lipid disorder are:

- Familial combined hyperlipidemia (FCH) is the familial occurrence of this disorder, probably caused by decreased LDL receptor and increased ApoB.

- 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.

Familial hypertriglyceridemia is an autosomal dominant condition occurring in approximately 1% of the population. Triglyceride levels, but not cholesterol, are elevated as a result of excess hepatic production of VLDL or heterozygous LPL deficiency. The condition is associated with premature coronary disease, though treatment sometimes differs from hypercholesterolemia. Affected individuals are at risk for chylomicronemia syndrome, characterized by elevated chylomicrons in the blood. They are also at risk of pancreatitis, especially when triglyceride levels exceed 1000mg/dL.

Around 80 cases have been reported in the literature worldwide, hence this condition appears to be relatively rare. More than likely, sitosterolemia is significantly underdiagnosed and many patients are probably misdiagnosed with hyperlipidemia.

Apolipoprotein B deficiency (also known as "Familial defective apolipoprotein B-100") is an autosomal dominant disorder resulting from a missense mutation which reduces the affinity of apoB-100 for the low-density lipoprotein receptor (LDL Receptor) . This causes impairments in LDL catabolism, resulting in increased levels of low-density lipoprotein in the blood. The clinical manifestations are similar to diseases produced by mutations of the LDL receptor, such as familial hypercholesterolemia. Treatment may include, niacin or statin or ezetimibe.

It is also known as "normotriglyceridemic hypobetalipoproteinemia".

Sitosterolemia (also known as "Phytosterolemia") is a rare autosomal recessively inherited lipid metabolic disorder. It is characterized by hyperabsorption and decreased biliary excretion of dietary sterols (including the plant phytosterol beta-sitosterol). Healthy persons absorb only about 5% of dietary plant sterols, but sitosterolemia patients absorb 15% to 60% of ingested sitosterol without excreting much into the bile. The phytosterol campesterol is more readily absorbed than sitosterol.

Sitosterolemia patients develop hypercholesterolemia, tendon and tuberous xanthomas, premature development of atherosclerosis, and abnormal hematologic and liver function test results.

An inherited disorder associated with the deposition of a steroid known as cholestanol in the brain and other tissues and with elevated levels of cholesterol in plasma but with normal total cholesterol level; it is characterized by progressive cerebellar ataxia beginning after puberty and by juvenile cataracts, juvenile or infantile onset chronic diarrhea, childhood neurological deficit, and tendineous or tuberous xanthomas.

Cerebrotendineous xanthomatosis or cerebrotendinous xanthomatosis (CTX), also called cerebral cholesterosis, is an autosomal recessive form of xanthomatosis. It falls within a group of genetic disorders called the leukodystrophies.

Depending on ethnicity and geography, prevalence has been estimated to be between 1 in 40,000 and 1 in 300,000; based on these estimates the disease may be underdiagnosed. Jewish infants of Iraqi or Iranian origin appear to be most at risk based on a study of a community in Los Angeles in which there was a prevalence of 1 in 4200.

Some children with LAL-D have had an experimental therapy called hematopoietic stem cell transplantation (HSCT), also known as bone marrow transplant, to try to prevent the disease from getting worse. Data are sparse but there is a known high risk of serious complications including death, graft-versus-host disease.

Pseudohypoaldosteronism (PHA) is a condition that mimics hypoaldosteronism. However, the condition is due to a failure of "response" to aldosterone, and levels of aldosterone are actually elevated, due to a lack of feedback inhibition.

This syndrome was first described by Cheek and Perry in 1958. Later pediatric endocrinologist Aaron Hanukoglu reported that there are two independent forms of PHA with different inheritance patterns: Renal form with autosomal dominant inheritance exhibiting salt loss mainly from the kidneys, and multi-system form with autosomal recessive form exhibiting salt loss from kidney, lung, and sweat and salivary glands.

Treatment of severe forms of PHA requires relatively large amounts of sodium chloride.

These conditions also involve hyperkalemia.

Types include:

It has been documented, to date, in more than 120 males (see Human Tafazzin ("TAZ") Gene Mutation & Variation Database). It is believed to be severely under-diagnosed and may be estimated to occur in 1 out of approximately 300,000 births. Family members of the Barth Syndrome Foundation and its affiliates live in the US, Canada, the UK, Europe, Japan, South Africa, Kuwait, and Australia.

Barth syndrome has been predominately diagnosed in males, although by 2012 a female case had been reported.

Barth syndrome (BTHS), also known as 3-Methylglutaconic aciduria type II, is an X-linked genetic disorder. The disorder, which affects multiple body systems, is diagnosed almost exclusively in males. It is named after Dutch pediatric neurologist Masa Barth.

The disease has been reported to affect 3 per 1000 infants younger than 6 months in the United States. No predilection by race or sex has been established. Almost all cases occur by the age of 5 months. The familial form is inherited in an autosomal dominant fashion with variable penetrance. The familial form tends to have an earlier onset and is present at birth in 24% of cases, with an average age at onset of 6.8 weeks. The average age at onset for the sporadic form is 9–11 weeks.

Cortical hyperostosis is a potential side effect of long-term use of prostaglandins in neonates.

A xanthoma (pl. xanthomas or xanthomata) (condition: xanthomatosis), , is a deposition of yellowish cholesterol-rich material that can appear anywhere in the body in various disease states. They are cutaneous manifestations of lipidosis in which lipids accumulate in large foam cells within the skin. They are associated with hyperlipidemias, both primary and secondary types.

Tendon xanthomas are associated with type II hyperlipidemia, chronic biliary tract obstruction, and primary biliary cirrhosis. Palmar xanthomata and tuboeruptive xanthomata (over knees and elbows) occur in type III hyperlipidemia.

Xanthoma tendinosum (also tendon xanthoma or tendinous xanthoma) is clinically characterized by papules and nodules found in the tendons of the hands, feet, and heel. Also associated with familial hypercholesterolemia (FH).

Gigantism is a rare disorder resulting from increased levels of growth hormone before the fusion of the growth plate which usually occurs at some point soon after puberty. This is most often due to abnormal tumor growths on the pituitary gland. Gigantism should not be confused with acromegaly, the adult form of the disorder, characterized by somatic enlargement specifically in the extremities and face.