The body depends on good nutrition for health, growth and function.

How does it utilize the food we eat? It does so by digesting and absorbing the food, in the process breaking it down to proteins and then amino acids, carbohydrates and fats. In addition we ingest vitamins, trace elements and other food constituents. The process by which all these are used and turned into the body’s requirements is called metabolism. For good health, growth and development, energy, body function (including our internal organs like the heart, brain, kidneys, liver, muscles and so on), healing and immunity, and reproductive health we need a normal metabolic system.

When there is a problem with metabolism, one or more of these processes is liable to go wrong and we become ill. This is called a metabolic disease. Metabolism is closely controlled by genes and so when there is a genetic fault, called mutation, this may affect our metabolism and cause a metabolic disease. This type of metabolic disease is called an Inborn Error of Metabolism (IEM). Other kinds of metabolic disease may occur as a result of non-genetic causes such as over or under eating, or eating unbalanced diets, poisoning or other acquired causes. Even these kinds of disease however may also be affected by genes.

IEM may begin very early in life, even before birth, but they commonly become apparent after birth in the first days or months of life. Others may show up only later in childhood or even in adulthood. IEM can cause very many kinds of symptoms. In young babies, severe multi-system disorder with accumulation of acids in the body is a well-recognised pattern; low blood sugar or accumulation of chemicals (“metabolites”) in the body is also possible. Common symptoms are weakness, altered consciousness, seizures, breathing problems and severe vomiting. There may be a strange bodily smell. Later on here may be severe effects on physical and mental development. In one group of diseases there is massive accumulation in the body of waste materials, and this is called a storage disease.

When a gene mutation causes an IEM it is because the gene product, often a chemical catalyst called an enzyme, is missing or not working. The result is termed a “metabolic block”. Doctors can use the chemical results of a metabolic block to help identify the nature and severity of a block and diagnose the specific disease. This can now be done in a growing number of cases even before the patient becomes ill, by using screening tests from a simple blood-spot test usually taken in the first week or so of life. Once a diagnosis is made the doctor can often help by prescribing special diets, giving supplements and in some cases special drugs (either orally or intravenously). In severe cases intensive care may be needed and life-saving treatments such as dialysis and transplants may be necessary. Since genes can now usually be identified, all families with IEM in a family member should receive genetic counselling. By early and appropriate treatment, good follow-up, education and counseling, most IEM today can be prevented or at least managed to minimise  damage. Nevertheless this kind of disease remains a major challenge for the patients and their families, as well as for physicians.

As can be seen metabolic diseases are life threatening inheritable, genetic disorders in which errors of metabolism occur, involving a block where a catalyst or enzyme is absent or malfunctioning. This defect results in the build up of chemicals on one side of the metabolic blockage and a deficiency of vital chemicals on the other. This causes an overdose of one or more, often toxic, chemicals and the shortage of others, which are essential to normal body functioning.  The consequences of such chemicals are often fatal, leading to either a slow deterioration with progressive physical and mental issues, or to rapid decline and death.
 
For some metabolic disorders, treatments are available and a few others can be managed by diet, however, many of these must be continued for life.  Much research is still needed to find new and better treatments.

Climb is committed to fighting metabolic diseases through research, awareness and support. We are the UK's only dedicated organisation to provide information and support on all metabolic diseases to children, adults, families, carers and professionals.

Back to Top