Tulane University's Hayward Genetics Center is one of the first to offer a drug therapy designed to help PKU patients manage their condition when taken as a supplement to their diet regimen.

The drug, marketed as Kuvan, was approved by the Food and Drug Administration in mid-December 2007 but was prescribed in clinical trials at Tulane for more than a month before then.

Individuals with PKU are born with a deficiency in the activity of the enzyme called phenylalanine hydroxylase (PAH), says Hans Andersson, director of the Hayward Genetics Center. With little or no PAH activity, they are unable to metabolize an essential amino acid, called phenylalanine (Phe), which is found in most foods. When Phe cannot be metabolized by the body, abnormally high levels of it accumulate in the blood and are toxic to the brain. If left untreated, PKU can result in mental retardation and other neurological problems.

In the past, PKU patients had only one option to manage the disease ”a strict, low-protein diet to restrict Phe levels. Kuvan can reduce Phe levels in some patients. Andersson says he has several patients who have responded to the drug since early November 2007.

I am very excited about this approach to therapy because it is the first novel intervention we have had for PKU patients in over 30 years, says Andersson, an associate professor of pediatrics at Tulane.

While diet restrictions remain the primary therapy for PKU, some patients on Kuvan will be able to eat previously restricted foods, such as pizza or pasta, in limited quantities without consequence, Andersson says.

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Dr Johnstone sounds a note of caution about her findings: A paper published last year from the same study showed that low carbohydrate diets may have consequences for the health of the gut by dramatically reducing the numbers of particular types of bacteria. So we will be looking in more detail at the complex way in which we respond to changes in our diet before we can say whether low-carbohydrate ketogenic diets are a suitable tool for everyone who wants to lose weight.

When the phase of the study which involved the volunteers finished in October 2004, it attracted considerable interest because of its celebrity volunteer, Cameron Stout, who lost just over 12 kg during his nine week stay at the Rowett Institute. At the time, Cameron mentioned his surprise at not feeling hungry during the study and said he had adjusted to eating smaller portions. How does he feel now, three years later?

I had a great experience with the nutrition study at the Rowett. The food was excellent and the staff looked after us very well. Because I have such an irregular lifestyle I don ™t find it easy to stick rigidly to all that I learnt while I was at the Institute, but I try to make an effort most of the time. For me it was mainly about breaking bad habits “ and I guess we all have food vices we need to deal with! said Cameron.

For further information please contact Dr Sue Bird, KT Manager, Rowett Institute 01224 716668, 07711 093417. Alex Johnstone is available for interview “ please contact Sue to book a slot.

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