Metabolic diseases or disorders interrupt the normal processes of metabolism within the body, the many chemical reactions responsible for breaking down food and either using, storing, or disposing of the energy it contains. When something goes wrong with any of these processes due to lack of or excess production of an enzyme or hormone, a metabolic disease results. This leads to a substance building up in dangerous quantities, or to various deficiencies.
Causes of Inherited Metabolic Diseases
Metabolic diseases are inherited. Often, the disorder is caused by a faulty gene that has been passed down from family member to family member for generations, perhaps without previously manifesting. In most cases, the diseases only activate if both parents carry the gene. However, some metabolic diseases are inherited from the mother only.
Types of Metabolic Disease
Many different types of metabolic disease affect chemical processes within the body, and researchers discover more all the time. The severity of symptoms depends on which metabolic disease a person has. Some conditions, such as Tay-Sachs disease, prevent the body from producing the enzymes that break down particular substances within the body. As a result, the substances build up to harmful quantities. Metal metabolism disorders, such as Wilson’s disease, prevent the body from breaking down particular metals.
Individually, each metabolic disease is quite rare. However, metabolic disorders as a whole are more common. It is estimated than one in every 1000 to 2500 babies has a metabolic disease, but this count does not include individuals whose disorders are yet to be diagnosed. Certain ethnic groups, such as people of Ashkenazi Jewish heritage, are more likely to develop metabolic diseases.
Symptoms of metabolic disease vary as widely as the affected processes. Some may cause mild symptoms while others cause long-term disability and limit life expectancy. Some metabolic diseases cause digestive problems including pain in the abdomen, restricted appetite, vomiting, and weight loss. Such symptoms can lead to insufficient growth in children. Some diseases cause developmental delays and learning disabilities, while others lead to fatigue, seizures, and even comas.
In some cases, symptoms may appear very suddenly, such as when food or medicine triggers a metabolic disease. Other diseases worsen gradually over time. Some metabolic disorders become clear at birth, while others may not exhibit any symptoms for many years.
Doctors screen for some metabolic diseases routinely at birth, which results in quick detection of many serious conditions, regardless of visible symptoms. As technology progresses, medical practitioners can identify more and more metabolic diseases right away, enabling preventative treatments and reducing future complications.
Without screening at birth, it is usually difficult to notice or diagnose a metabolic disorder until an individual begins exhibiting symptoms that existing research links to a specific disease. At this time, blood or DNA tests can help doctors identify the disorder and confirm a diagnosis.
Metabolic diseases are not curable. Instead, medical practitioners base treatment on the management of symptoms and limiting harm caused by the disease. If food or other substances trigger symptoms, a doctor or dietitian may place the individual on a special diet or eliminate particular medicines. Supplementary enzymes can help make up for the metabolic shortcomings. If symptoms develop because a substance has already built up to a harmful level in the body, treating the blood with certain additives can help reduce toxins.
Not all metabolic disorders cause long-lasting adverse effects. Many people successfully manage their condition with simple measures such as changes to diet. In these cases, life expectancy may be close to normal or normal. However, some metabolic diseases are fatal, such as OTC deficiency. Life expectancy for people with these diseases varies. For example, children with Tay-Sachs disease do not usually survive beyond about five years.
Metabolic syndrome is often confused with metabolic diseases, but it is a distinct condition. People with metabolic syndrome display a range of characteristics including obesity, high blood pressure, elevated blood sugar, and raised cholesterol levels. Having metabolic syndrome increases the likelihood of developing serious health conditions such as diabetes, stroke, or cardiovascular disease. However, with changes to diet and lifestyle, people with metabolic syndrome can often delay the onset of complications or even prevent them altogether.