An inherited biochemical variation due to genetic alterations in the genes encoding metabolic enzymes.

A rare enzyme deficiency; children with inborn errors of metabolism do not have certain enzymes that the body requires to maintain organ functions. Inborn errors of metabolism can cause brain damage and mental retardation if left untreated. Phenylketonuria is an inborn error of metabolism.

any of a number of diseases in which an inherited defect (usually a missing or inadequate enzyme) results in an abnormality of metabolism

A mutation that results in the absence of an enzyme, leading to a metabolic consequence that may be fatal.

An inherited genetic defect present from birth that causes a deficiency in the body's essential enzymes and impairs metabolism.

a disorder caused by an inherited defect in an enzyme pathway which affects the body's metabolism.

A congenital disorder which results from a change in a gene which causes a deficiency in the presence or activity of particular enzymes important for the functioning of the body's metabolism (see Genetics Fact Sheet 18: Newborn Screening for Genetic Conditions).

An inherited metabolic defect which results in deficient production or synthesis of an abnormal enzyme.

Inborn errors of metabolism comprise a large class of genetic diseases involving disorders of metabolism. The majority are due to defects of single genes that code for enzymes that facilitate conversion of various substances (substrates) into others (products). In most of the disorders, problems arise due to accumulation of substances which are toxic or interfere with normal function, or to the effects of reduced ability to synthesize essential compounds.