a hereditary disease caused by an inborn error of metabolism that results from an enzyme disorder.
An enzymopathy may be caused by the absence of an enzyme, a decrease in an enzyme’s activity, or the absence or incorrect synthesis of a coenzyme. Each of these abnormalities leads to a specific metabolic disorder and determines the clinical picture of the given enzymopathy. For example, abnormal metabolism of carbohydrates may be manifested by diabetes mellitus or galactosemia, abnormal metabolism of fats, by Tay-Sachs disease or Niemann-Pick disease, and abnormal metabolism of amiho acids, by alkaptonuria or albinism.
There are approximately 500 types of enzymopathies, of which many types are polymorphic and heterogeneous. In heterogeneous enzymopathies, anomalies of the genes that regulate the interaction of enzymes can have identical manifestations, since the enzymes that control different biochemical reactions often produce an identical metabolic result. Most enzymopathies are transmitted by autosomal-recessive inheritance.
Some enzymopathies, such as phenylketonuria, may be detected by proximate analysis during the first few days of life. Early diagnosis often facilitates the normalization of metabolism through diet, through the introduction of a needed substance into the body (replacement therapy), through hormone therapy, or through elimination of the excess metabolites that disrupt metabolism.
The technique of amniocentesis is a promising means of diagnosing enzymopathies. Medicogenetic consultation is an increasingly important means of preventing enzymopathies.