Metabolic Disorders

Birth defects are conditions or abnormalities which prevent parts of the body or body systems from functioning effectively. There are two main types of birth defect, including structural defects and functional defects; structural defects affect the actual structure and make-up of the organ or body system, while developmental (also known as functional) defects affect the ability to function properly.

There are many different types of birth defect and some are much more severe than others. The main types of birth defect are categorised as follows:

Defects which affect the brain and nervous system
Sensory birth defects
Metabolic disorders
Degenerative disorders

What are metabolic disorders?

Metabolic disorders are caused by inherited conditions or defects which affect the body’s metabolic system. The metabolic system is responsible for processing the food we eat and breaking it down to produce energy for the body to function; this is a complex process which involves enzymes. Many different types of enzyme are used during the digestion process, with some responsible for breaking food down and others responsible for breaking down and removing toxins from the body.

In most cases, metabolic disorders are inherited from both parents. There are many different types of metabolic disorders, which affect the body in different ways.

What causes metabolic disorders?

In most cases of birth defects, the cause is unknown; an abnormality or irregularity, which affects the genetic make-up of the cells, occurs at the point of conception and appears to happen for no known reason. Other possible causes of birth defects include infections, including toxoplasmosis and German measles, which affect the mother during pregnancy, exposure to harmful chemicals or environments or drinking or smoking during pregnancy.

Diagnosing metabolic disorders

Antenatal screening can often be used to detect metabolic disorders during pregnancy; in some cases, this can make early treatment possible and the baby can receive treatment while still in the womb.

In many cases, metabolic disorders are much more difficult to diagnose than other types of birth defect; this is because many birth defects produce obvious differences in physical appearance which are usually visible from birth and can be diagnosed fairly quickly. Metabolic disorders affect the ability to turn food into energy so it can take a while for symptoms to present and parents and doctors to realise that there are problems relating to the metabolic system. In many cases, children suffer similar symptoms to other types of disorder or birth defect and this may result in a misdiagnosis at first; further tests should be able to confirm the correct type of disorder and then a treatment plan can be drawn up.

Examples of metabolic disorders

Examples of metabolic disorders caused by birth defects include:

Hypothyroidism
Phenylketonuria
Galactosemia
Tay-Sachs disease

Treating metabolic disorders

Some metabolic disorders can be detected and treated during the pregnancy, while others, including Tay-Sachs disease, cannot be treated. If you find out your child has a metabolic disorder your doctor will discuss possible treatment options with you and will explain which courses of action are available.