Homocysteine and other vascular risk factors in patients with phenylketonuria on a diet

The aim of this study was to investigate the known risk factors, such as lipids, homocysteine and endothelin, for the development of coronary artery disease (CAD) in phenylketonuria (PKU) patients, depending on their diet. The PKU patients (n = 74) were divided into two groups. Group A (n = 34; mean age 6.78 +/- 1.5 y) adhered strictly to a diet and group B (n = 40; mean age 8.0 +/- 3.2 y) did not comply with the diet. The control group comprised 50 healthy non- PKU children. All groups were evaluated for blood levels of homocysteine and vitamin B-6 by high-performance liquid chromatography, vitamin B-12 and folate in serum by a radioassay, lipids by a routine method, and lipoprotein( a) and endothelin- 1 with an immunoassay. Homocysteine levels (28.65 +/- 3.3 mumol l(1)) were increased in group A compared with group B (6.86 +/- 1. 6 mumol l(1)) and the controls (6.9 +/- 2.0 mumol l(1)) (p < 0.001). Vitamin B-6 (10.7 +/- 10.9 nmol l(1)), vitamin B-12 (98.5 +/- 22.3 pmol l(1)), folate (2.35 +/- 1.3 nmol l(1)) and lipids were decreased in group A. The other vascular risk factors, which were not dependent on diet [lipoprotein( a) and endothelin- 1], did not differ among the three groups. Conclusion: PKU patients on a strict diet had low vitamin B-6, vitamin B-12 and folate levels resulting in moderate hyperhomocysteinaemia. The evaluation of these vitamins at short intervals and their supplementation could be an early measure in the prevention of CAD.