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Methylmalonic acidemia (MMA) is an inborn error of organic acid metabolism. Patients with severe disease develop many complications despite treatment; often, the disease progresses to severe damage of the central nervous system or to end-stage renal disease (ESRD). When medical treatment is ineffective, liver, kidney, or combined liver and kidney(More)
PURPOSE To achieve clinical validation of cutoff values for newborn screening by tandem mass spectrometry through a worldwide collaborative effort. METHODS Cumulative percentiles of amino acids and acylcarnitines in dried blood spots of approximately 25–30 million normal newborns and 10,742 deidentified true positive cases are compared to assign clinical(More)
BACKGROUND Disorders of creatine metabolism arise from genetic alterations of arginine:glycine amidinotransferase (AGAT), guanidinoacetate methyltransferase (GAMT), and the creatine transporter. We developed a strategy for the detection of AGAT and GAMT defects by measurement of guanidinoacetate (GAA) and creatine plus creatinine (Cr+Crn) in biological(More)
BACKGROUND Guanidinoacetate (GAA) and creatine (Cr) are reliable biochemical markers of primary creatine disorders. The aim of this study was to develop and validate a method for the determination of GAA and Cr in dried blood spot through the use of stable isotope dilution and flow injection analysis (FIA)-ESI-MS/MS. METHODS Dried blood spots were(More)
Dopamine transporter deficiency syndrome due to SLC6A3 mutations is the first inherited dopamine 'transportopathy' to be described, with a classical presentation of early infantile-onset progressive parkinsonism dystonia. In this study we have identified a new cohort of patients with dopamine transporter deficiency syndrome, including, most significantly,(More)
The aim of the study was to explore the outcome of neurocognitive deficits and neuroimaging correlates in young adult early treated phenylketonuric (PKU) patients. We conducted a longitudinal study of 14 PKU patients that were assessed for IQ and neuropsychological functioning including executive functions (EF) over 14 years of follow-up (age range at 1st(More)
We describe a boy affected by an early-onset severe encephalopathy (stagnation of psychomotor development, paroxysmal dystonic postures and movements of limbs, hypokinesia) due to tyrosine hydroxylase deficiency. High blood prolactin and low homovanillic acid in cerebrospinal fluid suggested the diagnosis. Genetic analysis revealed 3 new missense mutations(More)
BACKGROUND Pathogenesis and clinical consequences of white matter abnormalities on magnetic resonance imaging (MRI) in phenylketonuric (PKU) patients are incompletely known. OBJECTIVE To study white matter alterations progression and outcome and its relationships with phenylalanine levels and intelligence quotient (IQ) in early treated PKU subjects who(More)
PURPOSE To improve quality of newborn screening by tandem mass spectrometry with a novel approach made possible by the collaboration of 154 laboratories in 49 countries. METHODS A database of 767,464 results from 12,721 cases affected with 60 conditions was used to build multivariate pattern recognition software that generates tools integrating multiple(More)
The clinical diagnosis of Parkinson's Disease (PD) is not supported by Single Photon Emission Computed Tomography (SPECT) using dopamine transporter radioligand in 4-15 % of patients. It has been hypothesized that this phenomenon, named "Scans Without Evidence of Dopaminergic Deficiency" (SWEDD), may be an adult-onset dystonia. We investigated the(More)