Jessica Brown’s three-year-old son Stanley is forced to live on a severely-restricted diet after being diagnosed with the rare condition phenylketonuria (PKU).
The genetic disorder – which affects just one in 10,000 babies in the UK – means he is unable to break down an amino acid in protein that can reach dangerous concentrations in his blood.
Now Stanley’s family have called for the NHS to offer a drug called Kuvan which has successfully treated PKU sufferers across Europe.
It comes after a High Court ruling last year forced the NHS to review its decision to refuse to fund the treatment for an autistic seven-year-old boy with PKU.
Mrs Brown, from Halesowen in the West Midlands, told Sky News: “This treatment would be life-changing for Stanley.
“To pay for it ourselves, it would cost £15,000 a year while Stanley is little. That would go up to £30,000 a year when he’s an adult.
“But even if we could afford it, the systems are not in place to allow for it to be administered.
“Why are we failing to offer treatment that is available in so many other countries? My little boy needs it.”
Mrs Brown said Stanley has to avoid eating meats, nuts, fish and dairy products because of his condition and even some vegetables are restricted.
“Everywhere we go we have to take our own food,” she added.
“It’s huge pressure for myself and my husband, as well as Stanley’s grandparents and his nursery because if he has too much protein it is extremely dangerous.”
Kuvan was licensed in 2008 and is used as a standard treatment for PKU in a host of European countries, according to the National Society for Phenylketonuria (NSPKU).
They include Austria, Belgium, Bulgaria, Czech Republic, Denmark, Estonia, France, Germany, Hungary, Italy, Latvia, Lithuania, Luxembourg, Netherlands, Norway, Portugal, Romania, Russia, Slovakia, Slovenia, Sweden, Switzerland, Turkey and Ukraine, the charity says.
The NHS is due to re-evaluate the funding of Kuvan later this year, according to NSPKU.
A spokeswoman for the National Institute for Health and Care Excellence (NICE), which approves drugs made available on the NHS, said: “At the request of NHS England, NICE has been asked to look at Kuvan as part of its topic selection process.
“The topic is scheduled to be discussed by the group in September. If there is consensus reached with all the decision makers, work will begin on the appraisal in September.”