New hope for metabolic diseases

More than 20,000 families in the UK are said to be affected by metabolic diseases. Climb (Children Living with Inherited Metabolic Diseases) and the National Information Centre for Metabolic Diseases (both at www.climb.org.uk) have organised Metabolic Disease Awareness Week from 27 June to 3 July 2010 to encourage research and provide information and support to those affected by metabolic disease.

The range of metabolic diseases is huge. They are genetic disorders characterised by metabolism errors involving the absence or malfunction of an enzyme or hormone. This defect results in a build-up of chemicals on one side of the biochemical fault and a deficiency in vital chemicals on the other, leading to a slow deterioration in the patient’s physical and mental health or sometimes to a rapid decline and death.

Inherited metabolic diseases have also been known as “inborn errors of metabolism”, a term first applied just over 100 years ago by Sir Archibald Garrod, who noted that the principles of Mendelian inheritance could be applied to certain inherited diseases of metabolism. He formulated the “one gene, one enzyme” hypothesis and went on to describe the nature of recessive inheritance in many enzyme defects.

Some metabolic disorders can be treated by managing the diet, but genetic research may also help in future. Nature recently reported that scientists at Newcastle University had developed a technique to transfer genetic material between fertilised human eggs without carrying over the mitochondria. This may help prevent the transmission of serious inherited disorders known as mitochondrial diseases.

A child born using this technique could have properly functioning mitochondria while retaining most of the genetic information from its parents.