Children with Down syndrome being diagnosed and treated earlier thanks to world-first study by Irish researchers into arthritis

NOTE: This is an historical article. The term “Down’s arthritis” is no longer used; Down Syndrome Associated Arthritis is the appropriate term today.

One in fifty children with Down syndrome have juvenile arthritis, more than twice what was previously estimated, according to a ground-breaking new study carried out by Irish researchers into the disease.

The four-year project – undertaken at UCD School of Medicine in partnership with clinicians in Our Lady’s Children’s Hospital, Crumlin is supported by Arthritis Ireland, Down Syndrome Ireland and the National Children’s Research Centre – found that children with Down syndrome are 18-21 times more likely to suffer from the debilitating disease than children without Down syndrome.

The first of its kind worldwide, the study is now being expanded to define what might be driving the disease.

“If we understand why the disease is more prevalent in children with Down syndrome and what is causing it, then we can begin to look at better treatment options and ultimately a cure for the disease,” said clinical research fellow Dr Charlene Foley.

This research has also helped raise awareness about the condition so that children with Down’s Arthritis (DA) are diagnosed and treated in a more timely manner, leading to better clinical outcomes and quality of life for children with Down syndrome.

Parent and Down Syndrome Ireland member Catherine Looney from Donoughmore in Cork describes how she spent more than three years seeing various specialists for her daughter Ava (now 12) after she began having mobility issues.

“When Ava was five, she started having trouble walking and things progressed from there. Things got so bad that Ava would cry with pain every evening – as would I. What parent wants to see their child in pain?

“I went to see countless specialists, but unfortunately, many could not see past Ava’s Down syndrome. One physiotherapist told me that Ava had simply stopped walking because she was developing the habit of not walking. I was even refused a wheelchair so I had to carry her up and down the stairs.

“When I heard about the study, I jumped at it. Ava was diagnosed with Down’s Arthritis and started treatment straight away and we haven’t looked back since – it’s been truly life-changing,” she said.

Delayed diagnosis can lead to irreversible joint damage. This joint damage, and consequential functional impairment, is preventable if timely diagnosis and treatment is instigated.

“Juvenile idiopathic arthritis (JIA) affects over 1,200 children under the age of 16 in Ireland. Up until now, however, we knew very little about the incidence of arthritis in children with Down syndrome,” said John Church, CEO of Arthritis Ireland. “Investing in research to find new treatments and ultimately a cure for arthritis is one of our key objectives at Arthritis Ireland. This research adds significantly to our knowledge about the disease,” he added.

Down Syndrome Ireland Clinical Research Nurse Fiona McGrane is the only specialist nurse in Ireland for children with Down syndrome based in Tallaght Hospital. She said that Ava’s story is unfortunately not an isolated one.

“Down syndrome affects all the cells in the body. Along with Down syndrome come many specific health implications, such as Down’s Arthritis, and these are best dealt with by clinical specialists who have an overview of the multiple health needs of children and adults with Down syndrome.

“Children like Ava may be misdiagnosed or suffer due a delayed diagnosis because of a lack of awareness of Down’s Arthritis and other conditions common to children with Down syndrome. For this reason, we’re calling on the Government to fund further nurse specialist posts around the country,” she said.

“This research has fundamentally changed our perception of arthritis in children and young people with Down syndrome, and how it differs from children with JIA. Our recent follow-up research grant to Dr Foley looks in detail at the tissue, genetics and immune reactions in children with Down’s Arthritis to help us understand the cause of this disease,” said Dr Jacinta Kelly, CEO of the NCRC.

The research is being undertaken by UCD Newman Fellow Dr Charlene Foley, along with her mentors Dr Orla Killeen, consultant paediatric rheumatologist in OLCHC; Prof. Gerry Wilson, Arthritis Ireland chair of rheumatology, UCD; and Prof. Ursula Fearon, Arthritis Ireland chair of molecular rheumatology, Trinity College Dublin.

Notes for editors:

* You can view the Detailed Preliminary Findings here.

* We are very conscious of correct terminology, Down’s Arthritis is a clinical term and is not an abbreviation for Down syndrome.

A variety of medical conditions are associated with Down syndrome, including autoimmune disorders such as diabetes mellitus, coeliac disease and thyroid dysfunction. Arthritis also occurs, but is largely under-reported.

Previous research had estimated that its prevalence was 8.7/1000, compared with the JIA prevalence of 1/1000. Despite these suspected higher incidence and prevalence rates, arthritis is rarely recognised at onset, and is frequently under or misdiagnosed.

Children with Down’s Arthritis frequently present with a polyarticular arthritis, i.e. five or more joints are affected. Small joint involvement of the hands occurs in almost all cases, a feature that appears unique to the arthritis associated with Down syndrome.

With the help and support of the members and staff of Down Syndrome Ireland, a national screening programme was set up, offering children and young people with Down syndrome (aged 0-21 years) the opportunity to attend a local musculoskeletal screening clinic. In total, 550 children with Down syndrome were screened.

Screening involved taking a medical history and performing a full musculoskeletal examination. Children with suspected arthritis were invited to attend for consultant review at the National Centre for Paediatric Rheumatology (NCPR) in Our Lady’s Children’s Hospital Crumlin. At this appointment, diagnosis was confirmed, investigations carried out and management instigated as required.

Next Phase of Research

The next phase in the research is to define Down’s Arthritis in terms of what might be driving the disease process. The investigators plan to do this by exploring three key areas:

• Immunology: Exploring and measuring the type and number of immune cells in the blood from children with DA and comparing these results to three separate groups of children (children with arthritis without Down syndrome; children with Down syndrome and no evidence of arthritis, children without Down syndrome or arthritis);
• Histology: Examining tissue taken from the lining of joints in children with DA and comparing its appearance under a microscope with tissue taken from a child with arthritis without Down syndrome; and
• Genetics: Exploring known arthritis genetic susceptibility markers in children with DA to identify whether they are present and if, like in the arthritis that affects children without Down syndrome, they contribute to the risk of developing arthritis in children with Down syndrome.

Contact

Brian Lynch
Communications Manager
Arthritis Ireland
01 647 0203 / 086 185 7529
blynch@arthritisireland.ie       

Alice Coughlan
Research Grants Manager
National Children’s Research Centre
01 409 6419 / 087 618 6198
alice.coughlan@ncrc.ie