Glutaric aciduria type I misdiagnosed as Leigh's encephalopathy and cerebral palsy

Infant mice with glutaric acidaemia type I have increased vulnerability to 3-nitropropionic acid toxicity

Glutaric acidaemia type I (GA I) is an inborn error of metabolism caused by a deficiency of glutaryl-CoA dehydrogenase (GCDH) and is characterized clinically by striatal degeneration that almost always occurs in early childhood. A murine knockout model of GA I has the organic aciduria seen in the human disorder, but this model does not develop striatal degeneration spontaneously. 3-Nitropropionic acid (3NP), a succinic dehydrogenase inhibitor with specificity for the striatum, was investigated as a potential initiator of striatal degeneration in GCDH-deficient mice. This study shows that GCDH-deficient mouse pups are more susceptible to 3NP than their wild-type littermates, and that all mouse pups are more sensitive to 3NP as infants than as adolescents and adults. Increased sensitivity to 3NP early in life may model the developmental window for the striatal damage observed in human GA I.

Age at symptom onset predicts severity of motor impairment and clinical outcome of glutaric acidemia type 1

OBJECTIVES

In patients with glutaric acidemia type 1 (GAI), biochemical and molecular markers fail to predict the course of individual patients; therefore we sought to identify nonbiochemical variables that correlate with severity of motor deficits or overall clinical outcome.

STUDY DESIGN

Archival data was collected from 42 published articles describing 115 patients with GA1. A forward, stepwise, multiple regression analysis was used to find predictors for outcome.

RESULTS

Analyses show that in patients who did not have a precipitating illness before the first appearance of motor symptoms, the age at onset was significantly associated with the severity of motor impairments and overall clinical outcome. In patients who had a precipitating illness, the age at onset did not predict the outcome. In both groups of patients, basal ganglia degeneration, enlargement of spaces containing cerebrospinal fluid, and white matter abnormalities were indicative of a poorer prognosis. Treatment given after the appearance of symptoms was not associated with a better clinical outcome or fewer motor deficits.

CONCLUSION

Because the age at symptom onset can significantly predict the severity of motor deficits and the overall outcome, it is important to identify patients with GA1 as early as possible. Several studies suggest that presymptomatic treatment may prevent or postpone the onset of symptoms.

Neurophysiologic correlates of organic acidemias: a survey of 107 patients

The files of 107 patients with 19 different types of organic acidemia were reviewed retrospectively. Approximately 50% of the patients had abnormal electroencephalogram (EEG) at the time of initial study. In patients who had serial studies, the EEG deteriorated in 38% and improved in 15%. The predominant EEG abnormality encountered was slowing of the background activity in various degrees. Focal or generalized paroxysmal activity occurring in conjunction with slow background activity indicated a poor prognosis. Brainstem auditory evoked potentials (BAEP), visual evoked potentials (VEP), and somatosensory evoked potentials (SEP) were analyzed. The VEP was abnormal in 44%, BAEP in 39%, and SEP in 29% of the patients. Given the magnitude and frequency by which neurophysiological abnormalities occur in organic acidemias, neurophysiology testing provides complementary functional information and has an important place in the clinical work-up of these diseases.

Glutaric aciduria yype 1: First reported cases in three Saudi patients

The clinical and biochemical findings in three patients with glutaric aciduri Type 1 (GAT1) are presented. They had a normal postnatal period of three to 14 months. They developed sudden and severe encephalopathy following an infection or trauma (patient 3) that gradually progressed to severe dystonia, choreathetosis, spastic quadriplegia and mental retardation. Neuroradiologic studies of the brain revealed while matter disease and frontotemporal lobe hypoplasia. The urine findings by gas chromatography/mass spectrometry (GC)/(MS) were characteristic of GAT1. Since GAT1 is an organic acidemia without intermittent acidotic attacks, but primarily manifests with progressive encephalopathy, it is important to recognize the potential of its existence among handicapped children in chronic care facilities. The good clinical response in two of the patients urges early diagnosis in subsequent newborn siblings of the families with the disease. The diagnosis of three patients in less than two years indicate the need for neonatal screening for the recognition of this disease, among other treatable metabolic diseases, in Saudi Arabia.

Nutrition support for glutaric acidemia type I

Glutaric acidemia type I is a rare, autosomal recessive, inborn error of lysine and tryptophan metabolism. This disorder is caused by a defect in the mitochondrial enzyme glutaryl-coenzyme A dehydrogenase, resulting in permanent or episodic elevations of glutaric acid. Despite clinical variability, untreated children often experience progressive neurologic damage that frequently leads to death. Recent evidence suggests that a lysine- and tryptophan-restricted diet and pharmacologic therapy with oral riboflavin and L-carnitine may arrest the neurologic deterioration. Several cases of normal growth and development have been reported in children diagnosed and treated before neurologic insult. In this article, we review previously published experience with dietary and pharmacologic therapy and provide guidelines for nutrition support based on our experience of treating four affected children. We suggest that dietary restriction of lysine and tryptophan is a safe and potentially effective therapy for individuals with glutaric acidemia type I.

Neuroradiological findings in glutaric aciduria type I: report of four Japanese patients

We examined neuroradiological computerized tomography (CT) findings and the clinical course of four Japanese children with glutaric aciduria type I (GA1) whose enzyme activity of glutaryl-CoA dehydrogenase was undetectable. Brain CT in all cases examined showed low density white matter, fluid collection in bilateral frontotemporal regions (particularly surrounding the Sylvian fissures), enlargement of the lateral ventricles and slight atrophy of the basal ganglia. Although these findings seemed to be characteristic for GA1, they were unlikely to be more extended, at least over 2 years after infancy. The low density white matter was observed more evidently in the neonatal or early infantile periods than in later periods. The degree of enlargement of fissures in bilateral frontotemporal regions about the Sylvian fissures appeared to correlate with the severity of symptoms such as dystonia or choreoathetosis. Magnetic resonance images (MRI) in one case showed bilateral linear-shaped low intensity in areas of the external capsules and putamen on a T1-weighted image. These CT and MRI findings, as well as clinical symptoms such as choreoathetosis or dystonia, may suggest that metabolic abnormalities in GA1, such as glutaconate, are toxic to the extrapyramidal tract system in the central nervous system, and that the clinical symptoms of the patients are attributable to atrophy of basal ganglia. Brain CT may be useful in diagnosis and evaluation of the clinical course of GA1 patients.

Organic acidurias: a review. Part 1

Organic acidemias are disorders of intermediary metabolism that lead to accumulation of organic acids in biologic fluids, disturb acid-base balance, and derange intracellular biochemical pathways. Their clinical presentation reflects the resultant systemic disease and progressive encephalopathy. While in some organic acidemias, disturbed acid-base metabolism is the predominant presenting feature, in others it is less prominent or even absent. The etiologies of the more than 50 different phenotypes include impaired metabolism of branched-chain amino acids, vitamins, glucose, lipids, glutathione, and gamma-aminobutyric acid and defects of oxidative phosphorylation. Most organic acidemias present with neurologic manifestations, which include acutely or subacutely progressive encephalopathy that involves different parts of the nervous system. The age of presentation and the associated systemic, hematologic, and immune findings provide additional guidelines for differential diagnosis. We summarize major organic acidemias, while emphasizing their usual and unusual neurologic presentations.

Glutaric aciduria type I. Brain CT features and a diagnostic pitfall

Serial CT findings in an infant with glutaric aciduria type I (GA-I) are reported. The major CT features were dilatation of the insular cisterns, regression of the temporal lobes, with "bat wings" dilatation of the Sylvian fissures and hypodensity of the lenticular nuclei. CT changes preceded the onset of symptoms by 3 months. An improvement in the temporal lobe atrophy was seen after a period of treatment, coinciding with marked clinical improvement. A peculiar feature was the presence of external hydrocephalus, which diverted the attention from manifestations of the primary disease and thus constituted a diagnostic pitfall. The delineation and recognition of the characteristic radiologic manifestations of GA-I are essential for allowing an adequate radiologist/clinician interaction in diagnosing this inborn error of metabolism.

Glutaric aciduria type I: enzymatic and neuroradiologic investigations of two kindreds

Two kindreds with glutaric aciduria type I were investigated. Of 20 family members who underwent neurologic examination and organic acid analysis of urine, 18 had glutaryl-coenzyme A dehydrogenase (GDH) activity determined in cultured skin fibroblasts and 12 had computed tomographic brain scans. Six homozygotes were identified who had undetectable GDH activity and identical biochemical profiles (consisting of glutaric and 3-hydroxyglutaric aciduria, reduced serum carnitine concentrations, and frontotemporal atrophy). Serial computed tomographic brain scans of one homozygous infant demonstrated the sequential postnatal development of this atrophy during 3 years before the development of clinical manifestations. In three of the six homozygotes, including the father in one kindred, there were no clinical manifestations of glutaric aciduria type I. These findings raise questions about the value of prenatal diagnosis in predicting clinical manifestations in homozygous newborn infants.

CT-scan findings in an infant with glutaric aciduria type I

An infant presented at three weeks of age with a rapidly enlarging head and hypertonicity. The diagnosis of glutaric aciduria type I (GAI) was confirmed by the absence of the enzyme glutaryl-CoA dehydrogenase in fibroblast culture. A CT scan at that time showed diffuse attenuation of cerebral white-matter. Scans at five and 10 months of age showed loss of white-matter volume and diffuse cerebral atrophy, most prominent in the frontal and temporal regions. GAI should be considered in the differential diagnosis of infants and children with neurological dysfunction who have CT-scan findings of white-matter attenuation and/or cerebral atrophy, most prominent in the frontal and temporal regions, and/or changes in the basal ganglia or thalamus.

Glutaric aciduria type 1: biochemical investigations and postmortem findings

Glutaric aciduria type 1 (GA1; deficiency of glutaryl - CoA dehydrogenase) was diagnosed in a 6.5-month-old female infant. Despite a good biochemical response to dietary reduction of lysine and tryptophan, there was no clinical response to diet nor to riboflavin therapy and her neurological condition deteriorated progressively until her death at 10.5 months. At postmortem examination only mild neuropathological abnormalities were found in contrast to previous reports of this condition. High levels of glutarate were found in liver, skeletal muscle, heart muscle and aqueous humor. Eye fluid which is readily available, may be a useful material for the postmortem diagnosis of this, and other organic acidurias when urine is not available.