Does Dietary Treatment Cause Obesity In Phenylketonuria? Comparison Of Obesity Ratios Of Patients Receiving Dietary Treatment And Tetrahydrobiopterin Treatment

Phenylketonuria is treated by either with tetrahydrobiopterin (BH4) or with phenylalanine-restricted diet. Patients on diet group may have a tendency of consume carbohydrate-rich foods and henceforth a risk of developing obesity. In this study, the prevalence of obesity+overweight among phenylketonuria patients either treated with phenylalanine-restricted diet or with BH4 are compared. Patients with phenylketonuria were divided into two groups as on dietary treatment and on BH4 treatment. Body mass index (BMI), BMI-percentile and z-score values of patients were calculated and classified as malnutrition, normal-weight, overweight and obese according to their nutritional status. The annual mean phenylalanine level of each patient is also evaluated. The study was done retrospectively.Total of 130 patients were included. 77 were receiving diet (female (n,%):37, 48.1%; male (n,%):40, 51.9%) and 53 were receiving BH4 (female(n,%):33, 62.3%; male(n,%):20, 37.7%) respectively. According to BMI-z-score, 35.1% were obese+overweight in the diet group vs. 16.9% in the BH4 group. The percentage was significantly higher in the diet group (p = 0.02). Obesity+overweight percentages in female/male patient groups showed no significant difference. Considering the correlation between obesity+overweight and age in the BH4 group, the median age of the patients with normal weight+malnutrition were found as 46-months, and that of obese+overweight patients were 137-months (p=0,001). For the same correlation, there was no significant difference in the dietary treatment group (p = 0.92). Mean annual phenylalanine levels were significantly higher in obese+overweight patients (p=0.047) in the BH4 treatment group but this difference was not significant in the diet group (p=0.051). Patients on phenylalanine-restricted diet have a risk of obesity or overweight. Therefore, attention should be paid not only to the phenylalanine levels of these patients, but also to their weight control and dietary content

Evaluation of the effect of obesity, dietary glycemic index and metabolic profiles on the cardiovascular risk in children with classical phenylketonuria

Objectives: To compare the glycemic index(GI),obesity,echocardiographic,and arterial stiffness measurements with the healthy control group to evaluate the cardiovascular risk of pediatric classical phenylketonuria(PKU). Methods: The study was a prospective observational,involving 104 pediatric volunteers between 2019 and 2020.Two groups were formed:the PKU patient group and the healthy control group.These two groups were further divided into three subgroups:obese,overweight,and normal weight.The patients' anthropometric measurements,body fat analysis,biochemical analysis, GI and glycemic load(GL),arterial stiffness measurements,and echocardiographic findings were recorded. Results: The PKU patient group's glucose,total cholesterol,LDL,and HDL values were significantly lower than the healthy control group(p = 0.010 for glucose and p = 0.001 for total cholesterol,LDL and HDL).Triglyceride levels were higher in the PKU patient group than in the healthy controls(109.6 vs. 76.7 mg/dl,p = 0.001). GI and GL were significantly lower in the PKU patient group than in the healthy control group(GI 453 vs. 392.9,p = 0.017 and GL 101.1 vs. 85.5,p = 0.036).Left ventricular mass(LVM)-z-score and LVM index were significantly higher in the PKU group than in the healthy control group(LVM z-score 0.9 vs. 0.5,p = 0.014 and LVM index 38.9 vs. 32.7 g/m2.7,p = 0.001). A moderately statistically significant positive correlation was found between the mean phenylalanine(phe) value and pulse wave velocity(PWV) among the PKU patient groups(R: 0.477,p < 0.001).A moderately statistically significant positive correlation was also found between waist circumference and PWV in the PKU patient group(R:0.541, p < 0.001). Conclusions: Our study found that close follow-up of phe levels and PWV is more critical than obesity, GI, and GL in the cardiovascular evaluation of classical PKU patients.A large number of multicenter pediatric studies are needed in this area