Term

Definition

Acylcarnitine (AC)

An acylcarnitine is the product of acyl-CoA + carnitine. It is formed when an esterified fatty acid (an acyl CoA) enters inner mitochondria membrane and conjugates to carnitine to allow for transport of the fatty acid into the mitochondrial matrix for β-oxidation. If β-oxidation is impaired, as in VLCAD deficiency, acylcarnitine concentrations increase. The acylcarnitine most often elevated biomarker in VLCAD is C14:1 - a 14 carbon fatty acid with one double bond attached to carnitine.

Bezafibrates

A fibrate drug that increases the catabolism of triglycerides in muscle, fat and liver tissues. It is being studied in LC-FAO as a possible treatment for rhabdomyolysis.

Cardiomyopathy

A condition in which the heart muscle becomes enlarged and thickened and thus is less effective.

L-Carnitine

Carnitine is derived from the amino acids lysine and methionine and is essential for transporting long-chain fatty acids into the mitochondria for energy production.

Essential fatty acid (EFA)

Linoleic acid (LA) and alpha-linolenic acid (ALA) are essential fatty acids. They must be supplied in the diet and are needed to synthesize docosahexaenoic acid (DHA) and arachidonic acid (ARA).

Long-chain fatty acids (LCF)

Fatty acids with a carbon length of 14-20 found in dietary sources.

Medical Food

"Food which is formulated to be consumed or administered enterally under the supervision of a physician and which is intended for the specific dietary management of a disease or condition for which distinctive nutritional requirements, based on recognized scientific principles, are established by medical evaluation." Defined in section 5(b) of the Orphan Drug Act (21 U.S.C. 360ee (b) (3)

An example of this is a formula appropriate for VLCAD in which long chain fat content has been reduced and sources of MCT are added.

Medium chain triglycerides (MCT)

Fatty acids with a carbon length of 6-12 found in dietary sources. Medical food sources contain 6-10 carbon length.

Myoglobinuria

The presence of myoglobin in the urine, usually associated with rhabdomyolysis. Myoglobin can cause renal damage as the kidney filters its byproducts into the urine.

Rhabdomyolysis

A condition in which there is damage and breakdown of skeletal muscle, usually associated with severe muscle pain and elevated creatine kinase (CK) in the blood.

Triheptanoin

A triglyceride composed of three seven-carbon fatty acids (C7). Triheptanoin oil is an investigational product for LC-FAO disorders. The 3-carbon fatty acid produced from C7 promotes anaplerosis by producing succinyl-CoA for entry into the citric acid cycle.

Word/concept

Abbreviation 

kilocalorie

Kcal

Gram

g

Micromole per liter

µmol/L

Daily recommended intake

DRI

Protein

PRO

Vitamins (word)

lowercase v

Blood levels/concentrations

concentrations

elevated

↑

Critically elevated

↑↑

Lowered/reduced

↓

Critically lowered/reduced

↓↓

May be abnormal or not

±

Beta

β

Less than

<

Less than or equal to

≤

Greater than or equal to

≥

Greater than

>