Harvey L. Levy

Maternal phenylketonuria and hyperphenylalaninemia. An international survey of the outcome of untreated and treated pregnancies.

Abstract Since many women with phenylketonuria (PKU) will have children of their own, we were interested in ascertaining the effect of maternal PKU and hyperphenylalaninemia on the offspring of suc...

Efficacy of sapropterin dihydrochloride (tetrahydrobiopterin, 6R-BH4) for reduction of phenylalanine concentration in patients with phenylketonuria: a phase III randomised placebo-controlled study

BACKGROUND Early and strict dietary management of phenylketonuria is the only option to prevent mental retardation. We aimed to test the efficacy of sapropterin, a synthetic form of tetrahydrobiopterin (BH4), for reduction of blood phenylalanine concentration. METHODS We enrolled 89 patients with phenylketonuria in a Phase III, multicentre, randomised, double-blind, placebo-controlled trial. We randomly assigned 42 patients to receive oral doses of sapropterin (10 mg/kg) and 47 patients to receive placebo, once daily for 6 weeks. The primary endpoint was mean change from baseline in concentration of phenylalanine in blood after 6 weeks. Analysis was on an intention-to-treat basis. The study is registered with ClinicalTrials.gov, number NCT00104247. FINDINGS 88 of 89 enrolled patients received at least one dose of study drug, and 87 attended the week 6 visit. Mean age was 20 (SD 9.7) years. At baseline, mean concentration of phenylalanine in blood was 843 (300) micromol/L in patients assigned to receive sapropterin, and 888 (323) micromol/L in controls. After 6 weeks of treatment, patients given sapropterin had a decrease in mean blood phenylalanine of 236 (257) micromol/L, compared with a 3 (240) micromol/L increase in the placebo group (p<0.0001). After 6 weeks, 18/41 (44%) patients (95% CI 28-60) in the sapropterin group and 4/47 (9%) controls (95% CI 2-20) had a reduction in blood phenylalanine concentration of 30% or greater from baseline. Blood phenylalanine concentrations fell by about 200 micromol/L after 1 week in the sapropterin group and this reduction persisted for the remaining 5 weeks of the study (p<0.0001). 11/47 (23%) patients in the sapropterin group and 8/41 (20%) in the placebo group experienced adverse events that might have been drug-related (p=0.80). Upper respiratory tract infections were the most common disorder. INTERPRETATION In some patients with phenylketonuria who are responsive to BH4, sapropterin treatment to reduce blood phenylalanine could be used as an adjunct to a restrictive low-phenylalanine diet, and might even replace the diet in some instances.

Effects of Untreated Maternal Phenylketonuria and Hyperphenylalaninemia on the Fetus

Abstract We studied the effects of maternal phenylketonuria and hyperphenylalaninemia on 53 offspring from untreated pregnancies in 22 mothers who were identified by routine screening of umbilical-cord blood. The IQ of the offspring was significantly correlated with both maternal IQ (r = 0.83, P 1100 μmol per liter) in the mother has a substantial cognitive effect on her offspring but that the effect of mild hyperphenylalaninemia may have been overst...

A derangement in B12 metabolism leading to homocystinemia, cystathioninemia and methylmalonic aciduria

Abstract In mammals, vitamin B 12 derivatives are known to function as coenzymes for two reactions: (a) methionine formation from 5-methylfolate-H 4 and homocysteine and (b) isomerization of methylmalonyl-CoA to succinyl-CoA (Weissbach and Dickerman,1967; Hogenkamp, 1968 ). We have recently investigated an infant with abnormalities of both the sulfur amino acids and methylmalonic acid. This paper summarizes the results of our investigation which indicate the occurrence of a hitherto unrecognized metabolic abnormality, a defective ability to accumulate the coenzymatically active derivatives of B 12 . As far as we are aware, this is the first proven instance of deranged vitamin metabolism in a human.

A derangement in B12 metabolism associated with homocystinemia, cystathioninemia, hypomethioninemia and methylmalonic aciduria☆

Abstract An infant is described who died at seven and one half weeks of age and whose clinical manifestations included poor feeding, hematemesis, melena, normocytic anemia and failure to gain weight. He was found to accumulate abnormally large amounts of cystathionine, homocystine and homocysteine-cysteine mixed disulfide and to have low concentrations of methionine in blood and urine. In addition he manifested a marked methylmalonic aciduria that did not respond to the intramuscular administration of vitamin B, (cyanocobalamin). Enzymatic analyses of liver, kidney and brain obtained at autopsy revealed specifically deficient activity in the B,-dependent enzyme, N,-methyltetrahydrofolate-homocysteine methyltransferase. Studies of fibroblasts grown from skin obtained ante mortem showed that the activity of the B--dependent enzyme, methylmalenyl-CoA (coenzyme A) isomerase, also was deficient, but this activity could be restored by growing the cells in medium containing excess hydroxocobalamin. Analysis of liver and kidney revealed that the concentration of deoxyadenosyl cobalamin (coenzyme-B,) was abnormally low whereas the concentration of total B, was high in serum and normal in liver. Apparently this infant could not adequately metabolize B, and as a result failed to accumulate coenzymatically-active derivatives of vitamin B, in normal amounts. It is suggested that therapeutic benefit may derive from the administration of forms of 6, that could circumvent the metabolic block, by giving substances that could stimulate the non-B, -dependent methionine-synthesizing system or by the administration of methionine in large doses.

Sepsis due to Escherichia coli in neonates with galactosemia.

Galactosemia, an inborn error of galactose metabolism, is characterized by jaundice, weight loss, lethargy and vomiting in the neonate and by cataracts, mental retardation and cirrhosis in later in...

Phenylketonuria Scientific Review Conference: State of the science and future research needs

New developments in the treatment and management of phenylketonuria (PKU) as well as advances in molecular testing have emerged since the National Institutes of Health 2000 PKU Consensus Statement was released. An NIH State-of-the-Science Conference was convened in 2012 to address new findings, particularly the use of the medication sapropterin to treat some individuals with PKU, and to develop a research agenda. Prior to the 2012 conference, five working groups of experts and public members met over a 1-year period. The working groups addressed the following: long-term outcomes and management across the lifespan; PKU and pregnancy; diet control and management; pharmacologic interventions; and molecular testing, new technologies, and epidemiologic considerations. In a parallel and independent activity, an Evidence-based Practice Center supported by the Agency for Healthcare Research and Quality conducted a systematic review of adjuvant treatments for PKU; its conclusions were presented at the conference. The conference included the findings of the working groups, panel discussions from industry and international perspectives, and presentations on topics such as emerging treatments for PKU, transitioning to adult care, and the U.S. Food and Drug Administration regulatory perspective. Over 85 experts participated in the conference through information gathering and/or as presenters during the conference, and they reached several important conclusions. The most serious neurological impairments in PKU are preventable with current dietary treatment approaches. However, a variety of more subtle physical, cognitive, and behavioral consequences of even well-controlled PKU are now recognized. The best outcomes in maternal PKU occur when blood phenylalanine (Phe) concentrations are maintained between 120 and 360 μmol/L before and during pregnancy. The dietary management treatment goal for individuals with PKU is a blood Phe concentration between 120 and 360 μmol/L. The use of genotype information in the newborn period may yield valuable insights about the severity of the condition for infants diagnosed before maximal Phe levels are achieved. While emerging and established genotype-phenotype correlations may transform our understanding of PKU, establishing correlations with intellectual outcomes is more challenging. Regarding the use of sapropterin in PKU, there are significant gaps in predicting response to treatment; at least half of those with PKU will have either minimal or no response. A coordinated approach to PKU treatment improves long-term outcomes for those with PKU and facilitates the conduct of research to improve diagnosis and treatment. New drugs that are safe, efficacious, and impact a larger proportion of individuals with PKU are needed. However, it is imperative that treatment guidelines and the decision processes for determining access to treatments be tied to a solid evidence base with rigorous standards for robust and consistent data collection. The process that preceded the PKU State-of-the-Science Conference, the conference itself, and the identification of a research agenda have facilitated the development of clinical practice guidelines by professional organizations and serve as a model for other inborn errors of metabolism.

The adult galactosemic phenotype

BackgroundClassic galactosemia is an autosomal recessive disorder due to galactose-1-phosphate uridyltransferase (GALT) deficiency. Newborn screening and early treatment do not completely prevent tremor, speech deficits, and diminished IQ in both sexes and premature ovarian insufficiency (POI) in women. Data on how individuals with galactosemia fare as adults will improve our ability to predict disease progression.MethodsThirty-three adults (mean age = 32.6 ± 11.7 years; range = 18–59) with classic galactosemia, confirmed by genotype and undetectable GALT enzyme activity, were evaluated. Analyses assessed associations among age, genotype, clinical features and laboratory measures.ResultsThe sample included 17 men and 16 women. Subjects exhibited cataracts (21%), low bone density (24%), tremor (46%), ataxia (15%), dysarthria (24%), and apraxia of speech (9%). Subjects reported depression (39%) and anxiety (67%). Mean full scale IQ was 88 ± 20, (range = 55–122). All subjects followed a dairy-free diet and 75–80% reported low intake of calcium and vitamin D. Mean height, weight and body mass were within established norms. All female subjects had been diagnosed with POI. One woman and two men had had children. Logistic regression analyses revealed no associations between age, genotype or gender with IQ, tremor, ataxia, dysarthria, apraxia of speech or anxiety. Each 10- year increment of age was associated with a twofold increase in odds of depression.ConclusionsTaken together, these data do not support the hypothesis that galactosemia is a progressive neurodegenerative disease. However, greater attention to depression, anxiety, and social relationships may relieve the impact of this disorder in adults.

Vitamin B6‐dependent seizures Pathology and chemical findings in brain

A 131/2h-year-old child died with vitamin B6-dependent seizures in progress. Microscopic findings in brain included an abnormally sparse quantity of central myelinated fibers in the cerebral hemispheres. Glutamic acid concentrations were elevated and GABA concentrations reduced in the frontal and occipital cortices but not in the spinal cord. All other amino acid concentrations were normal, except for increased cystathionine in the occipital cortex. Pyridoxal-5-phosphate (PLP) was reduced in the frontal cortex. Glutamic acid decarboxylase activity comparable to that of controls was detected when the PLP concentration was greater than 0.05 mM. These findings suggest that pyridoxine-dependent seizures in man are associated with reduced GABA concentrations in the brain and with diminished central white matter structures.

Newborn Screening of Lysosomal Storage Disorders

BACKGROUND Newborn screening is a state-based public health program established as a means for the early detection and treatment of certain medical conditions to minimize developmental disability and mortality. The program was initiated more than 40 years ago to detect and prevent phenylketonuria. Recent technological advances have expanded the scope of newborn screening to include more than 30 inborn errors of metabolism. Consideration is now being given to inclusion of screening for lysosomal storage disorders (LSDs). CONTENT Some lysosomal storage disorders (LSDs) express early in infancy or childhood and are treatable. Initiation of treatment in presymptomatic patients or in syptomatic patients before important symptoms are present may improve the long-term outcome. Therefore, early diagnosis is critical. Based on the availability of therapy and development of a screening method, 6 of the more than 40 known LSDs are candidates for newborn screening in the US: Gaucher disease, Pompe disease, Fabry disease, Niemann-Pick disease, mucopolysaccharidosis I, and Krabbe disease. This report reviews the history of newborn screening, the technology that has allowed for expanded screening during the last decade, LSDs and their treatment, and the evolving methods that might allow additional expansion of newborn screening to include certain LSDs. SUMMARY Recent and evolving technological advances may be implemented for newborn screening for LSDs. This screening will identify presymptomatic newborns, allowing for early treatment and prevention or limitation of morbidity otherwise associated with these inherited rare diseases.