Gene clues in human diseases

UK scientists have discovered that alterations in a single gene could increase the risk of several autoimmune disorders, including Type 1 diabetes, Graves disease and autoimmune hypothyroidism. The researchers, based at the Universities of Cambridge and Birmingham in the UK, published their findings in the journal Nature online.

Autoimmune disorders occur when the body's immune system starts to attack its own tissues. The CTLA-4 gene makes a protein that is thought to prevent this process, by acting as a 'brake' on the immune system. In Type 1 diabetes, the insulin-producing cells in the pancreas are lost, while Graves disease and hypothyroidism both affect the thyroid gland.

Lead researcher John Todd said although the study will not lead to immediate benefits for patients, obtaining information about the many different genes involved in autoimmune disease means that 'way off in the future we will understand what is really causing the disease'. He also said that if the causes were understood, 'it should be possible to modulate the primary reasons why some people develop this disease and others don't'.

Also published last week, in Science, was the identification of a mouse gene mutation that may help scientists understand the genetic basis of motor neurone disease (MND). The researchers, based in London and Germany, found that mice with an altered version of a gene called Dnchc1 developed an MND-like illness. Their findings 'open up a promising new avenue of research into definitive causes of MND and will doubtless accelerate our search for a cure' said Brian Dickie of the UK's MND Association.

The Dnchc1 gene mutations caused the death of motor neurones in the mice, the nerves that connect the brain to different parts of the body. A similar process occurs in humans in the disease Amyotrophic Lateral Sclerosis (ALS), and other types of MND. The symptoms, including a progressive muscle weakness, often do not appear until middle-age. Lead researcher Elizabeth Fisher said that the key question in MND research had been the link between specific gene mutations and the loss of motor neurones.