Scientists have created a new classification of common diseases based on how often they occur among genetically-related individuals and say the system could change how some diseases are treated.
Using data from more than 480,000 people in nearly 130,000 families, the scientists estimated genetic and environmental correlations between diseases, with some unexpected observations. They found migraine appears to be most genetically similar to irritable bowel syndrome and most environmentally similar to cystitis and urethritis.
The scientists also compared their results to the International Classification of Diseases Version 9 (ICD-9) and found additional, unexpected groupings of diseases. High genetic correlations were observed across common, apparently dissimilar diseases such as asthma, allergic rhinitis, osteoarthritis and dermatitis, while type 1 diabetes had a high genetic correlation with hypertension.
"Understanding genetic similarities between diseases may mean that drugs that are effective for one disease may be effective for another one," said Andrey Rzhetsky, senior author. "And for those diseases with a large environmental component, that means we can perhaps prevent them by changing the environment."
The findings are published in Nature Genetics.