A routine test on twins revealed a far from routine condition, and now their parents are fighting for greater awareness of PKU. Jacqui Morley reports
A little knowledge can be a dangerous thing. Ask Corrina and Nick Lunn, of Hawes Side Lane, parents of twins Benjamin and Emily, two-and-a-half years old.
Twins are a handful at the best of times and, with the best will in the world, this has not been the best of times.
Nick has packed in work to become a full time house dad. Disability living allowance, to which they were eligible, has finally been won – but only after one appeal failed, and the couple took it to tribunal.
The twins have PKU. Medics define Phenylketonuria (PKU) as an “autosomal recessive metabolic genetic disorder characterized by a deficiency in the hepatic enzyme phenylalanine hydroxylase.”
Still no wiser? Roughly, it boils down to this: The twins’ intake of protein has to be controlled to the nth degree. They have an inherited enzyme deficiency that can result in progressive development delay, severe learning difficulties or epilepsy, if not detected early.
There is no cure, but a controlled diet can help avoid the harmful effects.
Phenylalanine is an essential amino acid; the body must have it to grow and function properly. Too much can be harmful, so the body uses the enzyme phenylalanine hydroxylase to convert it into tyrosine. In PKU, levels of this enzyme are low, which means only limited amounts of phenylalanine are converted. As a result, phenylalanine build ups in blood and body tissues, particularly the brain, where it can cause severe and irreversible damage.
But Nick and Corrina can’t cut protein completely from the twins’ diet, as they still need the other amino acids to thrive.
It makes meal times a fine balancing act, from foods on prescription, others weighed out, intake monitored. Unlike most other youngsters, the twins can’t go to playgroup and share a friend’s sarnies or sweeties or enjoy a glass of milk. Protein, remember.
It means regular visits to the Royal Manchester Children’s Hospital and the trailblazing Willink Biochemical Genetics Unit there.
It means shopping takes longer because labels aren’t just checked for calories, or nuts, or e-additives, but the amount of protein contained.
Corrina admits to having dreaded Christmas “because of all the lovely things they couldn’t have.”
The twins are permitted the equivalent of a cube of cheese for their daily protein intake – and that cube can’t be consumed in one helping. That’s at its most simplistic. But it gets PKU into perspective.
Corrina is a speech and language therapist. They’re in short supply in NHS ranks, in spite of being in the spotlight since the King’s Speech film highlighted the work of one maverick.
Corrina would like more publicity of other elements of speech therapy, the work with people with special needs or learning difficulties or other challenges to overcome.
They all need a voice.
The lobby for greater awareness of PKU needs a louder voice than most – the National Society for Phenylketonuria helps provide it.
As a therapist, Corrina has assisted a little boy who has learning difficulties and seizures because of PKU. What she didn’t realise, until some time after the shock diagnosis in her own children, was that it had gone undetected in his case, for he was born in a country which didn’t have the heel prick test, which is routine for newborns here. The test picks up sickle cell anaemia, PKU and other conditions. “When we were told the twins had PKU, I thought of him and was devastated. It was worst case scenario.”
The twins had been breastfed for five days before a midwife broke news of the test result to the couple. “We were in shock,” says Nick. “It was such a routine test we hadn’t given it a second thought.”
It turned out both parents were carriers. Breast feeding had to stop, the twins’ levels of the potentially-harmful enzyme were well above safe limits. They changed to a formula feed, on prescription. “That hurt too,” says Corrina. “I felt terrible. Breast was best, and all that.”
They consider it a kind of blessing that both children, though not identical twins, have PKU, “because at least it means we can treat them the same, rather than let one have something and the other not, which could be a real problem in later years.”
There’s a chance they could revert to more normal food, after their crucial development ceases, although the brain continues to regenerate.
The Lunns aren’t so sure. “I know of teenagers who have gone on protein and report problems,” says Corrina. “It’s not a risk we want to take.”
Meantime, the twins are full of beans (in the metaphorical sense), chatty and playful, and enjoy having dad at home. “It made sense for me to keep my job, as I earned more,” adds Corrina.
It leaves Nick to explain PKU to well meaning friends and the occasional relative who offer a treat to the twins and protest, when dad says no. They say ‘aw, come on, just one won’t hurt’, but I have to say it will, actually,” concludes Nick.
For more information visit www.nspku.org