FILE - A researcher injects DNA material onto a laboratory dish.
FILE - A researcher injects DNA material onto a laboratory dish.

Scientists have discovered genetic links that could put them closer to finding better treatments for a range of diseases, including multiple sclerosis, juvenile diabetes, lupus and arthritis.   

Their genetic research has led to a road map pinpointing the origins of 21 such autoimmune diseases.  The disorders are caused when the body’s immune system that is supposed to protect it, mistakenly attacks healthy tissues or organs. The genetic blueprint resulting from this research could lead to the discovery of drugs that target more than one disease.
Researchers have identified as many as 100 autoimmune diseases that affect hundreds of millions of people around the world.  Of these, the biological underpinnings of 21 common diseases have now been identified.

Autoimmune diseases tend to share certain biological characteristics and may cluster together in patients.  So says David Hafler, chair of the department of Neurology at Yale University in New Haven, Connecticut.

“This provides a glimpse of why the diseases are shared.  In fact, thyroid disease and diabetes often go together.  Rheumatoid arthritis and lupus go together, and MS and Crohn’s disease go together.  And this is because of the shared genetic structure,” says Hafler.

Writing in the journal Nature, Hafler and colleagues from Massachusetts General Hospital, the Massachusetts Institute of Technology's and Harvard University’s Broad Institute unveil a genetic blueprint, identifying the origins of almost two dozen autoimmune diseases within the vast human genome.

‘A non-biased road map’

Hafler says the findings do not yet help doctors diagnose specific diseases, but could eventually lead to effective treatments.

“I think the most important part of these findings is...finally having a molecular understanding of each autoimmune disease - more important, a non-biased road map of what we should be targeting,” says he.

Hafler says there are some 300 to 400 known genetic variants involved in causing autoimmune diseases that are spread out across the entire human genome.  He says the disease-causing genes tend to be located near regions that are important for regulating immune function and give them a lot in common.

“What’s become very clear is that these autoimmune diseases do very, very much share a genetic variation together and really cluster together as one autoimmune disease.  So, they are very similar and share perhaps 20, 30 percent of identity of a genetic variance, but they're also different,” says he.

Hafler explains there are two types of genetic disease - one where there is a mutation in a particular gene, such as in the case of muscular dystrophy, that causes the disorder.  Most autoimmune diseases, however, are a complex blend of normally helpful genetic variants that all people carry but in some individuals, result in illness.  

Hafler says because some of the illnesses share the same biological pathways, it may be possible to develop or uncover existing drugs to treat more than one autoimmune condition.

The blueprint pinpointing the genetic origins of autoimmune diseases, according to Hafler, will be made available to scientists around the world to help them further understand and find treatments for these difficult and often debilitating conditions.