Parenteral nutrition in patients with inborn errors of metabolism - a therapeutic problem

Parenteral nutrition is now a standard part of supportive treatment in pediatric departments. We describe four cases in which parenteral nutrition was extremely difficult due to coincidence with inborn errors of metabolism. The first two cases was fatty acid beta-oxidation disorders associated with necrotizing enterocolitis and congenital heart disease. Thus, limitations of intravenous lipid intake made it difficult to maintain a good nutritional status. The third case was phenylketonuria associated with a facial region tumour (rhabdomyosarcoma), in which parenteral nutrition was complicated because of a high phenylalanine content in the amino acid formulas for parenteral nutrition. The fourth patient was a child with late-diagnosed tyrosinemia type 1, complicated with encephalopathy - during intensive care treatment the patient needed nutritional support, including parenteral nutrition - we observed amino acid formula problems similar to those in the phenylketonuria patient. Parenteral nutrition in children with inborn errors of metabolism is a rare, but very important therapeutic problem. Total parenteral nutrition formulas are not prepared for this group of diseases.

Molecular genetics of PKU in Poland and potential impact of mutations on BH4 responsiveness

Tetrahydrobiopterin (BH4) has been recently approved as a treatment of patients with phenylketonuria. However, as a confirmation of BH4-responsiveness, it might require a very expensive trial treatment with BH4 or prolonged BH4-loading procedures. The selection of patients eligible for BH4-therapy by means of genotyping of the PAH gene mutations may be recommended as a complementary approach. A population-wide genotyping study was carried out in 1286 Polish phenyloketonuria-patients. The aim was to estimate the BH4 demand and to cover prospectively the treatment by a National Health Fund. A total of 95 types of mutations were identified. Genetic variants corresponding with probable BH4-responsiveness were found in 28.2% of cases. However, patients with mild or classical phenylketonuria who require continuous treatment accounted for 11.4% of the studied population only. Analysis of the published data shows similar percentage of the "BH4-responsive" variants of a PAH gene in patients from other countries of Eastern Europe. Therefore, it can be concluded, that the proportion of phenylketonuria-patients who could benefit from the use of BH4 reaches approximately 10% in the entire region.

Molecular genetics of PKU in Poland and potential impact of mutations on BH4 responsiveness

Tetrahydrobiopterin (BH4) has been recently approved as a treatment of patients with phenylketonuria. However, as a confirmation of BH4-responsiveness, it might require a very expensive trial treatment with BH4 or prolonged BH4-loading procedures. The selection of patients eligible for BH4-therapy by means of genotyping of the PAH gene mutations may be recommended as a complementary approach. A population-wide genotyping study was carried out in 1286 Polish phenyloketonuria-patients. The aim was to estimate the BH4 demand and to cover prospectively the treatment by a National Health Fund. A total of 95 types of mutations were identified. Genetic variants corresponding with probable BH4-responsiveness were found in 28.2% of cases. However, patients with mild or classical phenylketonuria who require continuous treatment accounted for 11.4% of the studied population only. Analysis of the published data shows similar percentage of the "BH4-responsive" variants of a PAH gene in patients from other countries of Eastern Europe. Therefore, it can be concluded, that the proportion of phenylketonuria-patients who could benefit from the use of BH4 reaches approximately 10% in the entire region.

Phenylketonuria is not a risk factor for gut mucosa inflammation: a preliminary observation

BACKGROUND

Phenylketonuria (PKU) is an inborn error of amino acid metabolism in which high phenylalanine (Phe) concentrations in the central nervous system adversely affect its development and functioning. In PKU high oxidative stress and inefficiency of free radical scavenging may lead to systemic chronic inflammation. We hypothesised that in PKU gut mucosa is chronically inflamed and that this leads to release of calprotectin from neutrophils and monocytes.

AIM

The aim of this study was to compare intestinal mucosa inflammation status, as measured using fecal calprotectin, in patients with PKU irrespective of compliance, and healthy controls.

PATIENTS AND METHODS

Forty-four patients with classical PKU were included in the study (21 male, 23 female; aged 0-41 years; mean ± SEM: 16.5 ± 1.7 years). Forty-eight healthy subjects (HS) aged 9-68 years (29.4 ± 2.6 years) comprised the control group, of whom 21 were male and 27 female. Among PKU patients 25 had normal Phe blood concentrations and in 19 they were elevated. In all subjects calprotectin stool concentrations were assessed (PhiCal ELISA, Calpro, Lysaker, Norway).

RESULTS

Normal FC (fecal calprotectin) concentrations were found in 43 (97.7%) PKU patients and 46 (95.8%) HS. No correlation between dietary control of Phe blood concentrations and FC levels in PKU patients was found.

CONCLUSIONS

No detectable intestinal inflammation occurs in phenylketonuria. Lack of dietary control and elevated Phe levels do not seem to be risk factors for inflammation of the mucosa of the gut.

Quality of life in noncompliant adults with phenylketonuria after resumption of the diet

BACKGROUND

Discontinuation of dietary therapy in adults with phenylketonuria can lead to neuropsychological abnormalities and emotional problems. The aim of our study was to assess the change in quality of life in adult patients returning to the diet and to define the reasons for failure in diet resumption.

METHODS

Quality of life was assessed by means of the Psychological General Well-Being Index before study entry and subsequently after 3 and 9 months. Reasons for failure in diet resumption were analysed.

RESULTS

53 patients participated in the study. Initial quality of life assessment revealed severe distress in 17%, moderate distress in 28% and positive well-being in 55% of them. In the majority of patients with severe or moderate distress, improvement of subjective well-being was observed (especially in the domains of anxiety and depressiveness) if they managed to return to the diet (blood phenylalanine concentrations before study entry 0.78-1.62 mmol/L, mean 1.16 mmol/L; average blood phenylalanine concentration decrease by 0.42 mmol/L). Only 29 persons managed to maintain the diet for at least 3 months and only 10 participants finished the entire 9-month study protocol. Problems with dietary treatment while at work, the high cost of low-protein products and poor knowledge regarding proper diet were the most important factors responsible for failure in resumption of diet.

CONCLUSION

Interpersonal differences exist between adult patients on relaxed diet, in some of whom quality of life often remains good, while others can suffer from severe emotional distress. Returning to diet increases quality of life in the majority of patients.

Use of handheld computers for assessment of prefrontal cortex function in patients with phenylketonuria

Assessment of prefrontal brain cortex function can be helpful in treatment monitoring in patients with phenylketonuria. We aimed to assess the usefulness of computerized neuropsychological tests developed for handheld computers for this purpose. We observed worse test performance among persons with blood phenylalanine concentrations exceeding the recommended range. Use of handheld computers was assessed by patients and by doctors as interesting, not time-consuming and convenient. This method can be helpful during routine follow-up visits.