Spinal fluid 5-methyltetrahydrofolate levels are normal in Rett syndrome.
Explore the source record for details and available documents.
Adolescent↗
Biomedical subjects
K Hyland
Publications and source records attributed to K Hyland.
Effects of AAV-2-mediated aspartoacylase gene transfer in the tremor rat model of Canavan disease.
The tremor rat is a spontaneous epilepsy model with a seizure phenotype caused by a deletion in the aspartoacylase (ASPA) gene. The absence of ASPA expression in these animals results in undetectable levels of enzyme activity and the accumulation of the substrate N-acetyl-aspartate (NAA) in brain, leading to generalized myelin vacuolation and severe motor and cognitive impairment. In support of human gene therapy for CD, recombinant adeno-associated viral vector (AAV-2) expressing ASPA was stereotactically delivered to the tremor rat brain and effects on the mutant phenotype were measured. AAV-ASPA gene transfer resulted in elevated aspartoacylase bioactivity compared to untreated mutant animals and elicited a significant decrease in the pathologically elevated whole-brain NAA levels. Assessment of motor function via quantitative rotorod testing demonstrated that rats injected with AAV-ASPA significantly improved on tests of balance and coordinated locomotion compared to animals receiving control vectors. This study provides evidence that AAV-2-mediated aspartoacylase gene transfer to the brain improves biochemical and behavioral deficits in tremor rat mutants (tm/tm) and supports the rationale of human gene transfer for Canavan disease.
Amidohydrolases↗
Cerebral folate deficiency with developmental delay, autism, and response to folinic acid.
The authors describe a 6-year-old girl with developmental delay, psychomotor regression, seizures, mental retardation, and autistic features associated with low CSF levels of 5-methyltetrahydrofolate, the biologically active form of folates in CSF and blood. Folate and B12 levels were normal in peripheral tissues, suggesting cerebral folate deficiency. Treatment with folinic acid corrected CSF abnormalities and improved motor skills.
Adaptation, Physiological↗
Infantile Parkinsonism-dystonia and elevated dopamine metabolites in CSF.
Two girls and one boy are described, with severe infantile parkinsonism-dystonia. This syndrome is usually caused by endogenous dopamine deficiency but in these patients was associated with elevated dopamine metabolites in CSF and an unusual eye movement disorder: ocular flutter together with saccade initiation failure. Pyramidal tract signs also emerged in the course of the disease in two patients. This combination of symptoms and biochemical findings suggests a unique pathogenic mechanism.
Dopamine↗
Aromatic L-amino acid decarboxylase deficiency: clinical features, treatment, and prognosis.
BACKGROUND: Deficiency of aromatic L-amino acid decarboxylase (AADC) is associated with severe developmental delay, oculogyric crises (OGC), and autonomic dysfunction. Treatment with dopamine agonists and MAO inhibitors is beneficial, yet long-term prognosis is unclear. OBJECTIVE: To delineate the clinical and molecular spectrum of AADC deficiency, its management, and long-term follow-up. RESULTS: The authors present six patients with AADC deficiency and review seven cases from the literature. All patients showed reduced catecholamine metabolites and elevation of 3-O-methyldopa in CSF. Residual plasma AADC activity ranged from undetectable to 8% of normal. Mutational spectrum was heterogeneous. All patients presented with hypotonia, hypokinesia, OGC, and signs of autonomic dysfunction since early life. Diurnal fluctuation or improvement of symptoms after sleep were noted in half of the patients. Treatment response was variable. Two groups of patients were detected: Group I (five males) responded to treatment and made developmental progress. Group II (one male, five females) responded poorly to treatment, and often developed drug-induced dyskinesias. CONCLUSIONS: The molecular and clinical spectrum of AADC deficiency is heterogeneous. Two groups, one with predominant male sex and favorable response to treatment, and the other with predominant female sex and poor response to treatment, can be discerned.
Adolescent↗
Phenylalanine loading as a diagnostic test for DRD: interpreting the utility of the test.
Phenylalanine loading has been proposed as a diagnostic test for autosomal dominant DRD (dopa-responsive dystonia), and recently, a phenylalanine/tyrosine (phe/tyr) ratio of 7.5 after 4 h was reported as diagnostic of DRD. To test the utility of this test in another sample with DRD, we administered an oral challenge of phenylalanine (100 mg/kg) to 11 individuals with DRD and one non-manifesting gene carrier. Only 6/12 had a 4 h phe/tyr ratio of greater than 7.5, suggesting that additional parameters must be set to avoid missing the diagnosis of DRD, including the need for the plasma phenylalanine to reach a minimum level 600 in order for the test to be valid. We propose that in cases where this minimum plasma phenylalanine level is not reached, plasma tetrahydrobiopterin should be measured or alternatively other symptomatic family members should be screened.
Adolescent↗
Tetrahydrobiopterin deficiency and dopamine loss in a genetic mouse model of Lesch-Nyhan disease.
Hypoxanthine-guanine phosphoribosyltransferase (HPRT) is an enzyme that catalyses the conversion of hypoxanthine and guanine into their respective nucleotides. Inherited deficiency of the enzyme is associated with a loss of striatal dopamine in both mouse and man. Although HPRT is not directly involved in the metabolism of dopamine, it contributes to the supply of GTP, which is used in the first and rate-limiting step in the synthesis of tetrahydrobiopterin (BH4). Since BH4 is required as a cofactor for tyrosine hydroxylase in the synthesis of dopamine, any limitation in the supply of GTP could interfere with the synthesis of dopamine. The current studies were designed to address the hypothesis that the reduced striatal dopamine in mice with HPRT deficiency results from reduced availability of BH4. The mutant mice had small reductions in striatal BH4, with normal BH4 levels in other brain regions. Liver BH4 was normal in HPRT-deficient mutant mice, and a phenylalanine challenge test failed to reveal any evidence for impaired hepatic phenylalanine hydroxylase, another BH4-dependent enzyme. Although striatal BH4 content is not normal, supplementation with BH4 or L-dopa failed to correct the striatal dopamine deficiency of the mutant mice, suggesting that BH4 limitation is not responsible for the dopamine loss.
Animals↗
Neonatal epileptic encephalopathy.
Explore the source record for details and available documents.
Aromatic-L-Amino-Acid Decarboxylases↗
Clinical and laboratory findings in twins with neonatal epileptic encephalopathy mimicking aromatic L-amino acid decarboxylase deficiency.
Aromatic L-amino acid decarboxylase (AADC) is a vitamin B 6 requiring enzyme involved in the biosynthesis of the neurotransmitters dopamine (DA) and serotonin. Lack of AADC leads to a combined deficiency of the catecholamines DA, norepinephrine (NE), epinephrine (E) as well as of serotonin. Here we describe premature twins who presented with severe seizures, myoclonus, rotatory eye movements and sudden clonic contractions. The patients showed an improvement of the clonic contractions under vitamin B 6 supplementation but died in the third week of life. In CSF and urine a biochemical pattern indicative of AADC deficiency was revealed. Concentrations of homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) were decreased, in association with increased concentrations of 3-ortho-methyldopa (3-OMD) in CSF and significantly increased vanillactic acid in urine. The AADC enzyme substrates L-dopa and 5-hydroxytryptophan (5-HTP) were elevated in CSF. Elevated concentrations of threonine as well as of an unidentified compound in CSF rounded off the biochemical pattern. AADC activity was found to be increased in plasma and deficient in the liver. Molecular studies effectively ruled out a genetic defect in the AADC gene. The basis for the epileptic encephalopathy in the twins may be located in the metabolism of vitamin B 6 and remains to be defined.
Aromatic-L-Amino-Acid Decarboxylases↗
Aromatic L-amino acid decarboxylase deficiency with hyperdopaminuria. Clinical and laboratory findings in response to different therapies.
Aromatic L-amino acid decarboxylase (AADC - E.C. 4.1.1.28) converts L-dopa to dopamine and 5-hydroxytryptophan to serotonin. Inherited deficiency of this enzyme leads to decreased brain levels of these neurotransmitters. Clinically this results in the development of a progressive neurometabolic disorder characterized by severe hypotonia, dystonic and choreoathetoid movements, oculogyric crises, and hypothermia from infancy. Here we describe the clinical, biochemical and molecular details of two affected brothers, one of whom, despite the lack of AADC, presented with hyperdopaminuria. In addition, we detail his reactions to treatment with dopaminergic agonists, monoamine oxidase inhibitors and pyridoxine.
Aromatic-L-Amino-Acid Decarboxylases↗
CSF dopamine, serotonin, and biopterin metabolites in patients with restless legs syndrome.
PURPOSE: To evaluate the role of CNS dopaminergic systems in Restless Legs Syndrome (RLS), homovanillic acid (HVA), tetrahydrobiopterin (BH4), and neopterin (NEOP), were assayed in CSF from RLS patients. The serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA), was also measured. METHODS: CSF was taken from 16 RLS patients after 2 weeks off medication and from 14 control subjects. The CSF metabolites were determined using HPLC techniques. RESULTS: There was no significant difference in HVA or 5-HIAA, but NEOP and BH4 were higher in RLS patients. The RLS group was significantly older than the control group (64.2 +/- 9.2 years vs. 51.4 +/- 6.3 years; P < 0.001). A multiple regression analysis showed a strong correlation between age and 5-HIAA (r = 0.46, P = 0.04) and between age and NEOP (r = 0.61, P < 0.01). To eliminate the potential error created by the age difference between groups, an age-adjusted subgroup of RLS and control subjects were compared. There was still no difference found for HVA; however, 5-HIAA was now significantly lower (P < 0.01) in the RLS subgroup. Age-adjustment eliminated the differences previously found for NEOP, (P = 0.12), but BH4 continued to remain higher in the RLS group (P < 0.01). CONCLUSION: Differences in CSF HVA concentrations were not found. The changes in 5-HIAA and BH4 are of unclear clinical significance and require further assessment with appropriate age-matched controls.
Age Factors↗
Parkinsonism, dystonia, and hemiatrophy.
Hemiatrophy has been reported in association with a variety of neurologic conditions, including parkinsonism. Patients with the hemiparkinson-hemiatrophy syndrome (HP-HA) have asymmetric parkinsonism with limb atrophy on the more affected side. Several authors have suggested that asymmetric brain damage early in life results in both atrophy and parkinsonism. Dopa-responsive dystonia (DRD) is a disease in which a deficiency of tetrahydrobiopterin, or, less commonly, of tyrosine hydroxylase, results in levodopa-responsive dystonia with parkinson features in children. We have recently identified four patients with DRD who had asymmetric dystonia and limb atrophy on the more affected side. Based on these patients, we suggest that a deficiency of the nigrostriatal dopamine system may, by itself, be sufficient to cause body atrophy and may underlie the limb atrophy in both DRD and HP-HA.
Adolescent↗
The influence of L-dopa on methylation capacity in aromatic L-amino acid decarboxylase deficiency: biochemical findings in two patients.
Explore the source record for details and available documents.
Amino Acid Metabolism, Inborn Errors↗
Monoamine changes in the brain of BALB/c mice following sub-lethal infection with Nocardia asteroides (GUH-2).
BALB/c mice injected intravenously with a single, sub-lethal dose of Nocardia asteroides GUH-2 develop several levodopa responsive movement disorders. These included headshake, stooped posture, bradykinesia, and hesitation to forward movement. The changes in monoamine levels in the brain of these mice were determined. There was a significant loss of dopamine with greatly increased dopamine turnover in the neostriatum 7 to 29 days after infection. These effects were specific for dopaminergic neurons since minimal changes were found in neostriatal norepinephrine and serotonin even though serotonin turnover was increased. Changes in monoamine metabolism were not limited to the neostriatum. There were reduced levels of serotonin and norepinephrine with increased serotonin turnover in the cerebellum. One year after infection, dopamine metabolism had returned to near normal levels, but many of the movement disorders persisted. Specific changes in neurochemistry did not always appear to correspond with these impairments. Nevertheless, these data are similar to those reported in MPTP treated BALB/c mice.
3,4-Dihydroxyphenylacetic Acid↗
Parkinson's disease and oral care.
Parkinson's disease is a relatively common, progressive, neurological disorder. Its key features of resting tremor, bradykinesia, akinesia, restricted mobility and postural instability militate against independence for daily living, mobility, good nutrition and oral health. The successful management of the disease requires a multi-disciplinary approach in which the dietician, speech therapist, nurse and dental staff are pivotal members of the care team.
Deglutition Disorders↗
Dopa-responsive dystonia due to a large deletion in the GTP cyclohydrolase I gene.
Although it is assumed that most patients with autosomal dominant dopa-responsive dystonia (DRD) have a GTP cyclohydrolase I dysfunction, conventional genomic DNA sequencing of the gene (GCH1) coding for this enzyme fails to reveal any mutations in about 40% of DRD patients, which makes molecular genetic diagnosis difficult. We found a large heterozygous GCH1 deletion, which cannot be detected by the usual genomic DNA sequence analysis, in a three-generation DRD family and conclude that a large genomic deletion in GCH1 may account for some "mutation-negative" patients with dominantly inherited DRD.
Adult↗
Clinical and therapeutic observations in aromatic L-amino acid decarboxylase deficiency.
OBJECTIVES: To elucidate the phenotype in aromatic L-amino acid decarboxylase (AADC) deficiency, a rare autosomal recessive disorder of neurotransmitter synthesis, and report preliminary treatment observations with directed therapy of the associated neurotransmitter deficiencies. BACKGROUND: AADC is a required enzyme in dopamine, norepinephrine, epinephrine, and serotonin biosynthesis. Five patients have been previously reported. Responses to treatment interventions in these patients have been mixed. METHODS: Clinical and biochemical evaluation and therapeutic trials were performed in two children over a 26-month period. RESULTS: Characteristic features included axial hypotonia, hypokinesia, and athetosis, with superimposed episodes of ocular convergence spasm, oculogyric crises, dystonia, and limb rigidity. Catecholamine deficiency was manifest by ptosis, nasal congestion, paroxysmal diaphoresis, temperature instability, and blood pressure lability. Abnormal sleep, feeding difficulties, and esophageal reflux were typical. Significant therapeutic benefit was observed in one child with a combination of pergolide, trihexyphenidyl, and tranylcypromine. Preliminary trials using serotonin receptor agonists or reuptake inhibitors resulted in adverse effects. CONCLUSIONS: The movement disorder in AADC deficiency, particularly the characteristic eye movement abnormalities, should facilitate the identification of patients with this rare but possibly underrecognized disorder. Directed therapy of the underlying dopamine and norepinephrine deficiency may be beneficial in some cases.
Amino Acid Metabolism, Inborn Errors↗
Short-term effects of high-dose 17beta-estradiol in postmenopausal PD patients: a crossover study.
OBJECTIVE: To examine the effect of 17beta-estradiol on the severity of the cardinal signs of PD in postmenopausal women. BACKGROUND: Although the impact of estrogens on the manifestations of PD has not been subjected to rigorous study, their use is generally thought to be associated with a detrimental antidopaminergic effect. METHODS: A double-blind, placebo-controlled, two-arm crossover study of high-dose transdermal 17beta-estradiol was conducted in eight postmenopausal women with mild to moderate PD, all but one of whom exhibited levodopa-induced dyskinesias. Patients were randomized initially to either hormonal treatment or placebo for 2 weeks, followed by a 2-week washout period, and then another 2-week crossover treatment period. Active treatment employed four skin patches each releasing 0.1 mg of estradiol daily, replaced every 2 to 3 days. RESULTS: After 10 days of treatment a significant reduction was observed in the antiparkinsonian threshold dose of IV levodopa. Mean duration and magnitude of the antiparkinsonian response to threshold or high doses of levodopa were unchanged, and dyskinesia scores were unaltered during 17beta-estradiol treatment compared with placebo. No worsening in "on" time or motor ratings with estrogen treatment was documented. CONCLUSIONS: 17beta-estradiol appears to display a slight prodopaminergic (or antiparkinsonian) effect without consistently altering dyskinesias. Standard postmenopausal replacement therapy with transdermal 17beta-estradiol is likely to be well tolerated by many female parkinsonian patients.
Administration, Cutaneous↗