Is basic bone profile affected in phenyloketonuria and hyperphenylalaninemia? The experience of the greek reference center

Abstract

Aim: Τo investigate the relationship between different basic bone profile biochemical parameters in Pheylketonuric patients.

Materials and Methods: Study participants included 100 phenylketonuria patients, males and females, with an average age 11,82 ±10,21 years, early diagnosed by Newborn Screening and dietary treated. Serum calcium, phosphate, magnesium, alkaline phosphatase, creatinine, albumin, triglycerides, cholesterol, HDL, LDL, vitamin D, hemoglobin and ferritin were determined for a routine biochemistry and total blood count. Z-BMI, Z-Wt and Z-Ht were estimated for the assessment of normal or delayed growth.

Results: no significant differences were observed to BMI, weight and height (Z-scores) in all subtypes of the disease (PKU-HPA), as well as in groups with good or poor compliance to diet. All the biochemical/ hematological measurements were within normal ranges. Significant differences (p<0.05) were presented with respect to phenylalanine levels (Phe) between the patients with good and poor compliance and to riglycerides, phosphorus and alkaline phosphatase between the subtypes of the disease. Interestingly, significant statistical differences were observed, between different age groups, such as prepubertal <11years and pubertal>11 years, in the follow biochemical factors: calcium, phosphorus, cholesterol, creatinine, phenylalanine levels and vitamin D. A negative correlation was found between vitamin D, phosphorus and ALP with Phe levels and a positive correlation between creatinine and Phe levels, in all patients. Finally, only in PKU patients, calcium was negatively correlated and Z-BMI was positively correlated to Phe levels. Conclusion: These findings suggest that a systematic and periodic biochemical monitoring of basic bone profile may be useful in order to detect and evaluate subtle changes in bone metabolism in Phenylketonuric patients.