I kept thinking: ‘is my son going to die when he is 11?’

Mother of nine-year-old with rare genetic disorder on diagnosis – and living positively

“All I kept thinking was ‘is my son going to die when he is 11?’.” Sharon Byrne remembers the fear she felt when she heard her son’s diagnosis of a rare degenerative genetic disorder when he was just two years old.

Sharon, who lives in Lucan, Co Dublin, said Karl (Swaine), who was her first child, was born a "perfectly healthy baby" on April 2nd, 2007.

“We had no concerns – he was hitting all his milestones and everything was fine,” she said.

“Then, in February 2009, I was changing his nappy one night and noticed his belly button stuck out.”


Concerned it could be a hernia, Sharon and her partner, Howard Swaine, brought their son to Tallaght Hospital to have him examined.

“The doctor who examined him thought he had an unusually large head. He said he would like to refer him to a paediatrician,” she said.

“Then the paediatrician just knew straight away [that Karl had a metabolic disorder] because he had certain facial features, like a flat nose.”

Sharon told the paediatrician her younger brother, Dessie Byrne, had a severe form of a metabolic inherited disease, called Hurler syndrome, and died in 1986 when he was only 11 years old.

“My brother never talked. He walked until he was nine, until he had a type of stroke and ended up in a special wheelchair. His bowel seized up, his lungs filled up with fluid. He had to be spoon fed and his food had to be liquidised, and he developed epilepsy – so I knew there was loads of things that could happen. It was scary,” she said.

Sharon said Karl was first tested for the same syndrome as her brother, but the results came back negative. The paediatrician persisted with the tests and Karl was officially diagnosed with Hunter syndrome in September 2009.

Enzyme deficiency

Both Hunter and Hurler syndrome are grouped under the mucopolysaccharidoses (MPS), which refers to a number of genetic disorders caused by a deficiency of a specific enzyme. There are a total of seven different disorders and each one has varying severities but they can share some features. There is no cure. Problems can develop in a child's skeleton, heart, lungs, brain, hearing and eyesight. Hunter syndrome is the second most common of the disorders in the republic of Ireland and Hurler syndrome is the first.

Sharon said the couple were “shocked” after hearing their son’s diagnosis.

“We had this beautiful two-year-old boy and suddenly our whole world came crumbling down because he had this condition. It’s degenerative, it was life threatening, it was all the other bits that go with it,” she said.

“It was devastating because of what I had gone through with my brother.”

Two months after the diagnosis Karl began a weekly intravenous infusion treatment that replaces the missing enzyme, and helps slows the progression of the condition and treats symptoms.

“Something just kicked in with me and I went into fight mode that I can’t sit around feeling sorry for myself, that I have to get on it to make the best of it for my child and that’s what we did,” she said.

“There’s about 11 children in Ireland with the condition and 2,000 cases worldwide, and each child is affected differently. With Karl, we are lucky at the moment as he’s got a milder version of it.”

Sharon said Karl, who is now nine years old, has been mainly affected in his joints but his internal organs are “doing well”.

“He has a leaking valve in his heart and a heart murmur but it’s steady. He’s talking.”

She said despite the difficulties Karl faced, he was “full of life”.

“He is lively, very kind, loving, cheeky and funny. Everyone who meets him adores him. He loves hugging people and asking them if they want a cup of tea,” she said.

“He goes through an awful lot in his life. He can’t have a normal life. He sees other children his age and he can’t do the things they do but he accepts it and doesn’t ask why.”

Tough road

She said international Rare Disease Day, on February 28th, was important to create awareness of lesser-known conditions people live with.

“It lets people know what the child goes through and the carers go through. It’s a life-long road and a tough road,” she said.

“All we want is for Karl to stay happy and stay as healthy as he possibly can be. We try not to think of the negatives because if you do, it would eat you up. We have to be positive.”

Dr Ellen Crushell, a consultant paediatrician at Temple Street Children's University Hospital and Our Lady's Children's Hospital in Crumlin, said there were about 70 children living with MPS in the State and they are treated at the National Centre for Inherited Metabolic Disorders at Temple Street hospital.

“Depending on the genetic mutation and the degree of deficient enzyme, there may be differing severity of MPS – even within the same disorder. For example within Hunter syndrome some mutations will cause a very severe form where the child may die in their teens but other less severe mutations may cause a milder form,” she said.

“However, even the milder or attenuated forms of these disorders are disabling and are associated with significant health problems.”

Rachel Flaherty

Rachel Flaherty

Rachel Flaherty is an Irish Times journalist