Mason: The first child with pyridoxine dependent epilepsy to be successfully treated with a medical diet by TIDE-BC

Mason was just 2 months old when he was put on anti-seizure medication. It quickly became evident that he was unresponsive to the medication and only responded to the vitamin B-6 (pyridoxine) and folinic acid therapy. However, once diagnosed with pyridoxine dependent epilepsy (PDE), a metabolic form of epilepsy, Mason began treatment which changed the course of both his life and his mother’s.
Without realizing it, Mason has helped lead the way for other children suffering from the same inborn error of metabolism. His treatment -a lysine restricted diet- is a medical therapy pioneered though TIDE-BC. Mason was among the first patients with PDE worldwide to be successfully treated by by this medical diet in conjunction with vitamin B6, a therapy which has been developed and studied by the TIDE-BC team in collaboration with German neurologists.
Mason lives in Sicamous, BC, with his mother, Connie. At six and a half years of age he has been seizure free on a lysine-restricted diet for 3 years. But it wasn’t smooth sailing getting to this point. Connie remembers how it felt when Mason began having seizures, when she suspected something might be wrong. “At first I thought he was such an easy baby and then all of a sudden he would tense up and shake” she said.
When, at 2 months of age Mason had a seizure, he was taken to the Vernon Hospital and then flown down to BC Children’s Hospital (BCCH), where he and Connie stayed for 2 weeks. At 8 months of age his seizures subsided with vitamin B6 and folinic acid therapy. Although the treatment appeared to working, at that point Mason didn’t have an official diagnosis, but it suddenly became apparent to Mason’s mom that if the vitamin therapy was interrupted, the seizures would start again.
“Sometimes I would run out of vitamin B6 and I noticed Mason would have a seizure. When I told the doctor this, she said right away that Mason has PDE.”

Receiving Diagnosis and Treatment

It wasn’t until Mason was one that he was diagnosed with PDE. Although it meant treatment could be accurately given, the diagnosis was still bitter sweet. “I was happy to know but I was also frightened,” Connie said.
“I was told that Mason might not walk or talk. But in my head I kept thinking he’s normal and will do everything, but it just wasn’t clicking for him.”
As a result of the diagnosis, Mason was taken off the anti-seizure medication and remained on vitamin B6 therapy. The lysine restricted diet was later initiated when he was three and a half, and his seizures were then controlled.
“When Mason started on the diet there was a dramatic change. At 5 years old he walked like a toddler and within a week of beginning the diet he was walking normally. I thought, ‘who is this kid?!’ I felt that there was so much judgment on me as a mom, so it felt good to see the improvement.”
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While 75-80% of PDE patients suffer cognitive impairment despite adequate Vitamin B6 therapy, the introduction of a lysine restricted dietary therapy is considerably more effective. Once the affected metabolic pathway was discovered, TIDE was the first world wide to develop and implement a medical diet to reduce neurotoxins in the brain. For Mason the dietary treatment resulted in significant reduction of these biomarkers as well as an improvement of epilepsy control and neurocognitive functioning.

The treatment requires monitoring by a specialized team of physicians and dieticians and includes regular blood and urine testing. As well, it requires compliance and dedication on the part of the parents and caregivers. Connie is a young, single mother, with a lot on her plate. But she was dedicated and enthusiastic about the treatment. “It’s a total life style change but I would never go back. I know that if we don’t stick to the diet, Mason will revert back.” Connie said.
“The lysine diet was hard at the beginning. The first time I went shopping I had a meltdown. Everything has protein and lysine. I left the store in tears. In time, I found foods that worked. And I try new recipes for variety for Mason.”

The Importance of Early Diagnosis

Dr. van Karnebeek, who co-founded TIDE-BC with Dr. Stockler, emphasizes the importance of early recognition of disorders such as Mason’s. “Early recognition allows for timely treatment, which prevents or minimizes brain damage. TIDE minimized brain damage and enabled this child to reach his full potential.

There are now more than 81 of such treatable rare conditions causing intellectual disability and related problems such epilepsy and autistic features. TIDE is the first group worldwide to systematically implement a protocol prioritizing the identification of these treatable diseases in global delay or intellectual disability, so as to ensure that each affected child can reach its full potential. Each of the 81 genetic conditions is very rare, but as a group these treatable IDs likely account for a few percent of all children with intellectual disability, which is considerable in view of the fact that ID affects 2-3% of all children worldwide.

TIDE demonstrates how cutting edge research can be translated from bench to bedside to benefit the patient and society as a whole through improved health outcomes and related cost-savings. Additionally, a PDE consortium has been established by TIDE to generate solid evidence for the effect of the lysine-restricted dietary therapy.
“I feel honored to work with families such as Mason’s, and respect their resilience and optimism, learning from them each day.”
Dr. van Karnebeek

Facing the Future

While it hasn’t been easy, Connie’s dedication, together with the ground-breaking treatment provided by physicians at BCCH and TIDE, has paid off. Mason is now six and half and he’s started grade 1, and importantly, he enjoys school. His teachers are very helpful, and he has a fulltime aide. Mason has also become quite social. “Before he was successfully diagnosed and treated, Mason was anti-social. Now he’s a social butterfly,” Connie said.

Because of Mason’s treatment, Connie’s life has also improved—knowing her son is moving ahead she can also move ahead with hers.
“He’s so happy. I feel blessed every day about the way everything has turned out for us.”

Patient Stories

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Contact Information

TIDE BC / Biochemical Diseases Clinic
BC Children's Hospital
Rm K3-208, ACB
4480 Oak Street
Vancouver, B.C. V6H 3V4

Phone: 604-875-2628 (administrative)
Phone: 604-875-2880 (clinic)
FAX: 604-875-2349