Abstract
There is a controversy whether, in addition to phenylalanine (PHE), products of PHE transamination are involved in the pathogenesis of phenylketonuria (PKU). We determined phenyllactate in plasma by HPLC and PHE by amino acid analysis monthly for half a year in 24 adult patients with classic PKU who had stopped diet. Phenyllactate was measurable in all plasma samples (mean: 52 μmol/l; range: 7-154; mean PHE: 1250 μmol/l; range: 670 - 1990) Phenyllactate and PHE were linearly correlated (r = 0.734 [n = 144] p<0.0001). The correlation was stronger for the PHE level from the same date than for the previous PHE level (r = 0.734 versus 0.646). This disproves the hypothesis that phenyllactate is a useful parameter of long-term dietary control in PKU. There was a positive correlation between phenyllactate, but not PHE, and quality of dietary control during the first 12 years of age aa judged by median values of all quantitative PHE determinations over 24 6-months periods (p<0.05). We find it difficult to interpret this observation. Patients with higher plasma phenyllactate at a given PHE also tended to have lower IQ values, although this correlation did not reach significance.
From our data regular monitoring ot plasma phenyllactate is not indicated in patients with PKU. However, the extent of PHE transamination could be are independent parameter influencing the quality of dietary control. Further correlative studies of mental and biochemical phenotype in PKU patients are indicated and may help to facilitate individual decisions on the necessity and quality of life-long dietary therapy.
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Hoffmann, G., Beigl, M., Kutscha, A. et al. 95 EVALUATION OF PLASMA PHENYLLACTATE IN PHENYLKETONURIA. Pediatr Res 36, 18 (1994). https://doi.org/10.1203/00006450-199407000-00095
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DOI: https://doi.org/10.1203/00006450-199407000-00095