Ciara (9) and Luke (4) Willetts, from Shankill, Co Dublin, were both diagnosed with PKU through the heel-prick test shortly after birth.
Their mother, Karen Willetts, said she and her husband had never heard of the condition when Ciara was diagnosed and were very concerned when told if there was no intervention, their daughter would have severe mental and physical disability.
Both children are now on very restricted diets and can only have 10g a day of natural protein. Two tablespoons of peas, for example, contain 1g; a Weetabix for breakfast contains 2.5g.
Their diet is broken down into parts, Ms Willetts said; natural protein, then foods without protein, such as grapes, apples and melons, and specially manufactured low-protein products such as pasta, milk and flour.
They must also drink a “pretty unpalatable” synthetic formula four times a day, which provides all the other elements of protein they need to grow, excluding phenylalanine, the specific amino acid the children cannot tolerate. And they require weekly blood tests to ensure their levels of phenylalanine are under control.
“Feeding them every day is a huge challenge,” said Ms Willetts.
“Every time we leave the house I have to make sure I have their synthetic protein with us and that wherever we are going, there is something they can eat or I have to bring it with us.”
When Luke, who has just started junior infants, was invited to a birthday party recently, Ms Willetts had to call the mother, ask what the other children would be eating and cook something similar for Luke to take with him.
Despite adhering to the diet, the children still have some difficulties with cognitive function and, in the future, bone density could be a problem.
If the new drug, Kuvan, was available, brain functioning would improve, Ms Willetts said, and the children would be able to tolerate higher levels of natural protein.
“The drug would ease the burden of PKU,” she said.
"I would urge manufacturers and the HSE to get together and work this out."
