Inherited metabolic disorders

Inherited metabolic disorders are genetic conditions that cause metabolic problems. Most people with inherited metabolic disorders have defective genes that result in enzyme deficiencies. There are hundreds of inherited metabolic diseases with very different symptoms, treatments and prognosis.

What is metabolism?

Metabolism refers to all chemical reactions that convert or use energy. A few prime examples of metabolism include:

Break down carbohydrates, proteins and fats in food to release energy.

Converts excess nitrogen into waste products excreted in urine.

Break down or convert chemicals into other substances and transport them in cells.

Metabolism is an organized but chaotic chemical assembly line. Continuous use, production, transport and discharge of raw materials, semi-finished products and waste. The workers on the assembly line are proteins like enzymes that cause chemical reactions.

Causes of inherited metabolic disorders.

In most inherited metabolic diseases, enzymes are either not produced by the body at all or are produced in an ineffective form. Missing enzymes are like absent workers on an assembly line. A lack of enzymes means toxic chemicals may build up, or necessary products may not be produced.

The code or blueprint that an enzyme produces is usually contained in a pair of genes. Most people with inherited metabolic disease examples inherit two defective copies of the gene -- one from each parent. The parents are carriers of the bad gene, which means they carry the defective copy and the normal copy.

In the parent, the normal copy of the gene compensates for the bad copy. Their enzyme levels are usually adequate, so they may not have symptoms of inherited metabolic disorders. However, children who inherit two defective copies of the gene cannot produce enough efficient enzymes and develop inherited metabolic disorders. This form of inheritance is called autosomal recessive inheritance.

The original cause of inherited metabolic disorders is a genetic mutation many generations ago. Passed down from generation to generation, preserving genetic mutations.

Each genetic metabolic disorder is very rare in the general population. Taken together, genetic metabolic disorders may affect about 1 in 1,000 to 2,500 newborns. In some ethnic groups, such as German Jews (Jews from Central and Eastern Europe), there is a higher prevalence of inherited metabolic disorders.