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Lysosomal storage disorders (LSDs), a heterogeneous group of inborn metabolic disorders, are far more common than most doctors presume. Although patients with a severe LSD subtype are often readily diagnosed, the more attenuated subtypes are frequently missed or diagnosis is significantly delayed. The presenting manifestations often involve the bones and/or joints and therefore these patients are
Objective: Exclusively breastfed infants with unrecognised cholestatic jaundice are at high risk of a vitamin K deficiency (VKD) bleeding. It is presently unknown whether (the size of) this risk depends on the degree of cholestasis. Since alpha-1-antitrypsin deficiency (A1AD) induces a variable degree of cholestasis, we assessed the risk of VKD bleeding in infants with cholestatic jaundice due to
Three-phosphoglycerate dehydrogenase (3- PGDH) deficiency is a rare recessive inborn error in the biosynthesis of the amino acid L-serine characterized clinically by congenital microcephaly, psychomotor retardation, and intractable seizures. The biochemical abnormalities associated with this disorder are low concentrations of L-serine, D-serine, and glycine in cerebrospinal fluid (CSF). Only two m
Background: The clinical severity of phenylalanine hydroxylase deficiency is usually defined by either pre-treatment phenylalanine (Phe) concentration or Phe tolerance at 5 years of age. So far, little is known about the course of Phe tolerance or the ability of both pre-treatment Phe and Phe tolerance at early age to predict Phe tolerance at later age. Aim: This study was conducted to investigate
This study investigated which methods patients and parents used to determine phenylalanine (Phe) intake and the relationship between the methods applied, age, and blood Phe concentration, as this practice had not been studied before in relation to metabolic control. A questionnaire was sent to 327 Dutch phenylketonuria patients (age 0-29 years) to investigate the method used to determine Phe intak
The timing and yield of metabolic studies for patients with neurodevelopmental disorders is a matter of continuing debate. We determined the yield of additional or repeated metabolic studies in patients with neurodevelopmental disorders. Patients referred to a tertiary diagnostic center for patients with unexplained neurodevelopmental disorders were included. Initial metabolic studies had been per
BACKGROUND: The recent discovery and specific functions of D-amino acids in humans are bound to lead to the revelation of D-amino acid abnormalities in human disorders. Therefore, high-throughput analysis techniques are warranted to determine D-amino acids in biological fluids in a routine laboratory setting. METHODS: We developed 2 chromatographic techniques, a nonchiral derivatization with chira
- In certain inborn errors of metabolism, an allogeneic stem cell transplantation is able to prevent disease progression. - This is only possible when the stem cell transplantation (SCT) is performed early in life, before cerebral involvement has occurred. - In addition to bone marrow and peripheral blood, unrelated umbilical cord blood appears to be an effective stem cell source as well. - There
OBJECTIVE. Newborns routinely receive vitamin K to prevent vitamin K deficiency bleeding. The efficacy of oral vitamin K administration may be compromised in infants with unrecognized cholestasis. We aimed to compare the risk of vitamin K deficiency bleeding under different propylactic regimens in infants with biliary atresia. PATIENTS AND METHODS. From Dutch and Danish national biliary atresia re
Hurler syndrome (HS) is a severe inborn error of metabolism causing progressive multi-system morbidity and death in early childhood. At present, stem cell transplantation (SCT) is the only available treatment that can prevent central nervous system disease progression in HS patients. Although SCT has been shown to be effective for several important clinical outcome parameters, the reported clinica
N-Methyl d-aspartate (NMDA)-receptor hypofunction has been implicated in the pathophysiology of schizophrenia and d-serine and glycine add-on therapy to antipsychotics has shown beneficial effects in schizophrenic patients. Nevertheless, previous studies have not shown consistently altered d-serine concentrations in cerebrospinal fluid (CSF) of schizophrenic patients. To confirm and extend these r
Amino acids are not only indispensable for protein synthesis but also play important cellular functions. In this chapter, the central nervous system (CNS) functions of serine, glycine, and threonine are discussed. Both the specific functions of the aforementioned amino acids and the functions of their derivatives are reviewed in relation to brain development and neurotransmission. In particular, f
Menkes disease is an X-linked recessive disorder characterized by neurological deterioration, failure to thrive, peculiar hair and death in childhood, secondary to mutations in the ATP7A gene. The ATP7A gene encodes for a copper transporting P-type ATPase (ATP7A), which is ubiquitously expressed. A defect of the ATP7A protein leads to both a reduced transport of copper from the intestine into the
BACKGROUND AND PURPOSE: Brain imaging is an integral part of the diagnostic work-up for metabolic disorders, and the bedside availability of cranial ultrasonography (cUS) allows very early brain imaging in symptomatic neonates. Our aim was to investigate the role and range of abnormalities seen on cUS in neonates presenting with metabolic disorders. A secondary aim, when possible, was to address t
Renal Fanconi syndrome developed rapidly in a 3-year-old Moroccan girl with established lysinuric protein intolerance. She was hospitalized because of lowered consciousness, uncoordinated movements and hepatosplenomegaly after a febrile period. Laboratory investigations revealed plasma ammonia 270 micromol/L (normal <70 micromol/L), ferritin 159 micromol/L (normal 2-59 micromol/L), LDH 1180 U/L (n
We review the role of two susceptibility genes; G72 and DAAO in glutamate neurotransmission and the aetiology of schizophrenia. The gene product of G72 is an activator of DAAO (D-amino acid oxidase), which is the only enzyme oxidising D-serine. D-serine is an important co-agonist for the NMDA glutamate receptor and plays a role in neuronal migration and cell death. Studies of D-serine revealed low
Background: The main purpose for measuring urinary free sialic acid (FSA) is to diagnose sialic acid (SA) storage diseases. Elevated amounts of conjugated sialic acid (CSA) are observed in several diseases indicating the need to quantify CSA as well. A LC-MS/MS method for quantification of FSA and total sialic acid (TSA) in urine is developed and validated. Methods: FSA is analyzed directly after
