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About Sickkids
About SickKids

June 8, 2009

International research team identifies autoinflammatory syndrome

A team of international researchers, including doctors at The Hospital for Sick Children (SickKids), has identified an autoinflammatory disorder of the bone and skin. Autoinflammatory diseases are made up of a group of genetic disorders that can cause recurrent and persistent inflammation lesions that can affect the skin, joints, bones, eyes, the GI tract and the nervous system, including hearing.

In this study, the scientists investigated a disease that begins days after birth, with bone lesions, skin eruptions, and inflammation of the connective tissue surrounding the bone. The condition could result in life-threatening systemic inflammation.

The syndrome is caused by a mutation in a gene called IL1RN, which encodes a protein called interleukin-1-receptor antagonist. This protein blocks the activities of another protein called interleukin-1β, which is associated with generalized inflammation as well as localized inflammation involving many systems. The study is published in the June 4, 2009 issue of the New England Journal of Medicine.

The researchers propose that this illness be referred to as a deficiency of the interleukin-1 receptor antagonist or DIRA.

“These findings expand the spectrum of patients with diseases of the innate immune system and have led to novel treatments for this, and likely related, disease,” says Dr. Ronald Laxer, Rheumatologist and Project Investigator at SickKids and Professor in the Departments of Paediatrics and Medicine at the University of Toronto. Other members of the SickKids team include Dr. Rayfel Schneider, Head of Rheumatology at SickKids, Associate Chair of Education, and Associate Professor in the Department of Paediatarics at the University of Toronto; Dr. Elena Pope, Head of Dermatology and Project Investigator at SickKids and Assistant Professor in the Department of Paediatrics at the University of Toronto and Dr. Paul Babyn, Radiologist-in-Chief and Associate Professor in the Department of Medical Imaging at the University of Toronto.

Researchers studied nine children from six families who exhibited symptoms of the condition. They found all the children had mutations in the IL1RN gene. They determined the gene was an autsomal recessive gene, meaning it occurs on a non-sex determining chromosome and both parents contribute mutated genes.

The children were treated with anakinra, a drug that is used to treat rheumatoid arthritis as well as other well-defined autoinflammatory syndromes and blocks interleukin-1β. All children treated with anakinra responded rapidly with dramatic clinical improvements. This further supports the belief that the mutation results in the inability to produce the interleukin-1-receptor antagonist.

“Although this disease is rare, it may point to clues about the mechanisms of more common illnesses like psoriasis and inflammatory arthritis,” says Laxer.