Active clinical trials for "Phenylketonurias"

Phenylketonuria (PKU) is a rare inherited metabolic disorder, where subjects are born with a genetic deficiency in the phenylalanine hydroxylase enzyme (PAH), which leaves them unable to convert Phenylalanine (Phe) into Tyrosine (Tyr). PKU patients have specific dietary needs and must follow a restrictive diet in the aim of preventing toxic levels of the amino acid phenylalanine (Phe) accumulation.

Newborn screening and early treatment prevent the most severe manifestations of phenylketonuria (PKU). However, executive functioning deficits, attention deficit disorder, slow processing speed, and visual-motor problems commonly occur. Many adults with this disorder also suffer depression and anxiety. In this study the investigators will examine adults with PKU on sapropterin dihydrochloride (Kuvan) treatment for PKU and compare their results to those of subjects with PKU not on Kuvan. Using magnetic resonance imaging (MRI) techniques, including novel MR spectroscopy (MRS) the investigators hope to discover why this distinct constellation of deficits occurs in PKU. Adult subjects with PKU will undergo a comprehensive MRI evaluations, including a novel method of MR spectroscopy to determine brain phenylalanine levels. In addition, participants will receive neurological and neuropsychological examinations and dietary evaluation.

This observational study seeks to establish evidence: that physiologic changes, unrelated to effect on the Phenylalanine Hydroxylase (PAH) enzyme, occur in Phenylketonuria (PKU) patients who are treated with sapropterin (Kuvan®) therapy, that these changes may be caused by enhanced neurotransmitter synthesis in the brain or an upregulation of gene expression (increasing the ability of genes to produce functional enzymes), and that beneficial changes in behavior and cognition, especially executive functioning skills may result. The objective of this study is to correlate any change in behavior and executive function skills of PKU patients who are non-responsive to sapropterin effect on the PAH enzyme, as defined by lowered blood PHE levels, with urine neurotransmitter levels and broad gene expression prior to and after sapropterin administration. Expected outcomes would include evidence of sapropterin effects on upregulation of enzymes other than PAH that control neurotransmitter synthesis, and any resulting correlation with behavioral and cognitive changes. The investigators hope this study will inform further detailed investigations into the biochemical and molecular actions of sapropterin (Kuvan®) that lead to increased understanding of possible treatment effects beyond a lowered blood PHE response.

Investigators at Washington University will examine the effects of sapropterin (Kuvan) on brain and cognition in individuals with phenylketonuria (PKU) using neuropsychological and neuroimaging procedures. Sapropterin is a medication developed by BioMarin Pharmaceutical Inc. that is approved by the FDA for treatment of patients with PKU to reduce phenylalanine (Phe) levels. Patients beginning treatment with sapropterin as standard clinical care will be enrolled in the study. As a first step, patients with PKU will receive baseline neuropsychological and neuroimaging evaluations 1 day prior to beginning treatment with sapropterin. Screening for response to sapropterin will occur over 4 weeks. At the end of 4 weeks, response to sapropterin will be reviewed. Patients with a reduction of ≥ 20% in blood Phe (i.e., responders) will receive follow-up neuropsychological and neuroimaging evaluations after 6 months of treatment with sapropterin. Patients (both responders and nonresponders) will receive long-term follow-up neuropsychological and neuroimaging evaluations 3 to 5 years after initial enrollment in the study. The focus of neuropsychological testing will be executive abilities, as these abilities are particularly susceptible to disruption in individuals with PKU. We hypothesize that improvements in these abilities will occur following treatment with sapropterin. For neuroimaging assessments, structural magnetic resonance imaging (MRI) will permit evaluation of changes in the structure and volume of the gray and white matter of the brain, whereas diffusion tensor imaging (DTI) will permit evaluation of microstructural white matter integrity.

Phenylketonuria (PKU) is an inherited inborn error of an amino acid phenylalanine (PHE) metabolism affecting 1:15,000 births. It is caused by a decreased activity of an enzyme in the liver called phenylalanine hydroxylase (PAH) which is important to convert PHE into tyrosine, another amino acid. Consequently, PHE accumulates in the blood leading to mental and developmental delays. Nutritional management is the primary choice of treatment that includes providing sufficient protein in the diet and at the same time restricting PHE. However the amount of protein to be given is unknown. A new technique called Indicator Amino Acid Oxidation (IAAO) will be used to determine the protein requirements in children with PKU (5-18y). The study will help treat and manage these children with sufficient protein to ensure proper growth and development. Current dietary recommendations range from 35-65 g/day and is based on factorial calculations. The investigators hypothesize that the protein requirement in children with PKU will be higher than the current mathematically calculated recommended intake of 35-65 g/day for the 5-18y children.

Phenylketonuria (PKU) is a rare disease where the level of phenylalanine (one of the amino acids) in the body is greatly increased. High levels can cause brain damage, especially in babies and children. This brain damage can be prevented if a special low phenylalanine diet is started soon after birth. A new drug, sapropterin, can also lower phenylalanine levels in some patients. PKU therapy is monitored by measuring the blood phenylalanine every week, with the goal to keep the level within a target range. Recently, studies have suggested that the variation in the blood phenylalanine may be just as important as the absolute blood phenylalanine level for brain outcome. The investigators will look at the variation in blood phenylalanine level over 24 hours to see how much the level changes. The investigators will measure this in patients with typical PKU who are compliant with the diet and in patients who are not compliant with the diet. The investigators will also measure this in patients with "mild" PKU who do not usually have as high levels of phenylalanine. Finally, the investigators will see if patients on sapropterin have lower variation.

A retrospective study to collect the effectiveness and safety data of the past treatment with KUVAN in Chinese patients with HPA caused by BH4 deficiency. The data was collected from relevant past medical history and past clinical and safety assessments.

This is a study about the relationship of brain biomarkers with neuropsychological functioning in PKU. All participants will undergo MRI spectroscopy, will provide a blood specimen and will receive neuropsychological testing.

lnborn errors of metabolism (IEM) are a heterogeneous group of rare, sometimes debilitating or even fatal diseases . In IEM, both definition and assessment of meaningful outcome parameters is often extremely difficult resulting in a limited body of evidence. Limited evidence results in weak recommendations which are perceived as unbinding and thus sustains heterogeneous study designs, choice of outcomes and interventions again producing non-uniform data. The goal of the current study is to identify and select reliable instruments, that measure patients' and their parents' perception about relevant (social, emotional, cognitive and physical) aspects in their lives. This set of instruments will secure the comparability of future research findings. Furthermore this instruments will improve the screening of paediatric IEM patients regarding their need for additional (psychosocial or consultative) support in daily hospital routine.

Hyperphenylalaninemia (HPA) is a rare metabolic disorder caused by a deficiency of the enzyme phenylalanine hydroxylase (PAH). Elevated plasma levels of phenylalanine (phe) cause mental retardation, microcephaly, delayed speech, seizures, eczema, and behavior problems. Adequate control of the plasma levels of phe by a phe-restricted diet can prevent the developmental and behavioral problems. The foundation of this diet is a phe-free medical product/formula made from free amino acids. Based on longitudinal studies, it has been reported that the most benefit is attained by individuals who maintain a phe-restricted diet throughout life. Despite the obvious benefits of the diet, it has been suggested that the dietary restrictions may be associated with poor bone health in these patients. However, data supporting this has been reported in studies with small sample sizes and/or inadequate sample populations that include children. There is a paucity of data on bone health in adults with HPA. The investigators propose an observational study to describe the bone health status among adults with a diagnosis of HPA and to compare them to established normative age and gender-specific values among healthy individuals. The investigators hypothesize that adults with HPA will have lower bone density as measured by a dual x-ray absorptiometry (DXA) scan compared to the established normative values.