Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0917816 (mental retardation)
 15,867 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Infantile spasm is an age-specific epileptic encephalopathy. Long-term intellectual outcome of affected infants remains poor. The pathogenesis of infantile spasms, as well as the development of mental retardation, remains unclear. Increased excitatory amino acid neurotransmission may play a role in neuronal dysfunction and epilepsy. To study the significance of cerebrospinal fluid excitatory amino acids in infantile spasms, we determined glutamate and aspartate concentrations in cerebrospinal fluid of 13 patients with infantile spasms and 13 controls. The aspartate level in cerebrospinal fluid of the patients with infantile spasms (968 +/- 416 nmol/l) was higher than the control group (426 +/- 272 nmol/l). No difference in the mean glutamate levels was found between the patients (966 +/- 395 nmol/l) and the controls (1135 +/- 594 nmol/l). The elevated aspartate levels in cerebrospinal fluid of the patients with infantile spasms might be secondary to change in metabolism of aspartate. Aspartate is an excitatory and neurotoxic neurotransmitter, which might have a role in triggering the spasms and the development of neuronal dysfunctions in the patients with infantile spasms.
 ...
PMID:Excitatory amino acid levels in cerebrospinal fluid of patients with infantile spasms. 947 11

Myotonic dystrophy (DM) is the most common adult muscular dystrophy and follows an autosomal dominant pattern of inheritance. Up to now, the clinical diagnosis of DM was based on symptoms presented such as encephalopathy, facies myopathica, paresthesia, atrophy, myotonia, mental retardation, cataract, diabetes, cardiac conduction defects and electromyography. Since 1991 the specific molecular defect in DM is known and a respective diagnosis is possible. The mutation responsible for DM is the expansion of an unstable trinucleotide repeat, (CTG)n, in the 3'-untranslated region of the myotonin protein kinase gene. It is now generally accepted that the CTG repeat length correlates with the clinical category and the age at onset of the disease; therefore genetic tests are essential in monitoring and management of DM-patients and their family members. Based on the average incidence in Europe about 1000 affected individuals can be expected in Austria, a high percentage of whom is, however, not recognized as carries of the DM-mutation. After having established a genetic diagnosis in Austria allowing the detection of this mutation in DM-patients and their relatives, improvement of the diagnostic procedure should be possible.
 ...
PMID:Myotonic dystrophy: molecular genetics and diagnosis. 949 72

In this case report a near-term infant with Glucose 6-Phosphate Dehydrogenase (G6-PD) deficiency had an unconjugated bilirubin level of 703 on the 11th day of life but maintained his haemoglobin levels above 11 gm/dl. At 4 months of age he demonstrated the clinical picture of Kernicterus: profound sensorineural deafness and evidence of encephalopathy. However, by 15 months of age his abnormal cerebral and motor signs had regressed to a near-normal level in parallel with a gradual improvement in hearing, which also reached normal levels, first in the right ear, then in the left. At this age residual mental retardation has not been excluded but his communication skills, though delayed by 4-6 months, were moving towards the level when they would be appropriate for his age.
 ...
PMID:Glucose 6-phosphate dehydrogenase deficiency with kernicterus: progressive late recovery from profound deafness. 957 22

Ornithine transcarbamylase deficiency is an X linked disorder and the most common inherited cause of hyperammonaemia. Fluctuating concentrations of ammonia, glutamine, and other excitotoxic amino acids result in a chronic or episodically recurring encephalopathy. A heterozygous female patient first presented with protein intolerance, attacks of vomiting, and signs of mental retardation in early childhood. At the age of 16 complex partial seizures occurred which were treated with sodium valproate. Seven days after initiation of valproate therapy, she developed severe hyperammonaemic encephalopathy with deep somnolence. The maximum concentration of ammonia was 480 micromol/l. After withdrawal of valproate, three cycles of plasma dialysis, and initiation of a specific therapy for the inborn metabolic disease, ammonia concentrations fell to normal values. The patient remitted, returning to her premorbid state. Valproate can cause high concentrations of ammonia in serum in patients with normal urea cycle enzymes and may worsen a pre-existing hyperammonaemia caused by an enzymatic defect of the urea cycle. Sufficient diagnostic tests for the detection of metabolic disorders must be performed before prescribing valproate for patients with a history of encephalopathy.
 ...
PMID:Hyperammonaemic encephalopathy after initiation of valproate therapy in unrecognised ornithine transcarbamylase deficiency. 959 92

Careful clinical delineation and advances in analytical methods have opened new possibilities for the detection of inherited neurometabolic disorders, some of which require specific CSF analyses for diagnosis. Although patients suffering from these disorders have recognizable phenotypes, there are strong indications that remain many undiagnosed, leading to a continuation of futile diagnostic searches and, for most disorders, withholding of available rational therapy. As there is still widespread uncertainty about when to perform specialist CSF investigations, it is the aim of this paper to define the place for CSF investigations in the diagnostic work-up of a child with an encephalopathy of unknown origin. Most neurometabolic disorders can be identified through serum, plasma and urine analyses in conjunction with neuroradiological investigations. Whenever CSF investigations are performed, the analysis should include quantitative determination of lactate, pyruvate and amino acids, the latter by methods especially suited for CSF, in addition to cells, glucose, protein, immunoglobulin classes, specific immunoglobulins, and an evaluation of the blood-brain barrier. If the disease course is non-progressive or if extracerebral symptoms are present in addition to an encephalopathy, e.g. endocrinological, hepatic, muscular or renal symptoms, investigations of metabolites in CSF over and above lactate, pyruvate and amino acids are generally noncontributary. Specific CSF investigations, which are discussed in detail, test metabolic pathways of brain metabolism, especially of neurotransmission. For a successful diagnosis of these defects, analyses must be planned individually, before CSF samples are taken, based on family history, clinical findings and disease course. Different determinations require different logistics from taking of the sample to shipment. One indication for specialized CSF analyses including biogenic monoamines and GABA is severe neonatal/infantile epileptic encephalopathy. In addition to a therapeutic trial of B6, folinic acid should be tried empirically for two to three days as the emerging syndrome of folinic acid responsive seizures appears to be the underlying cause in a sizable proportion of patients. In later infancy and childhood, defects in the metabolism of the biogenic monoamines may be suspected in patients with (fluctuating) extrapyramidal disorders, in particular Parkinsonism dystonia or more general "athetoid cerebral palsy", and vegetative disturbances. A severe epileptic encephalopathy and progressive mental retardation may be present. Neuroimaging findings do not show specific lesions. Determinations of folates and organic acids in CSF appear at present only warrantable individually in special constellations, e.g. classical clinical findings and disease course suggestive of glutaryl-CoA dehydrogenase deficiency with repeated negative quantitative analyses of organic acids in urine. The diagnosis of disorders, which require specific analyses of CSF, can only be achieved by conscious diagnostic decisions based on a concept of the respective disease and repeated scrupolous expert clinical evaluation aided by an array of investigations in blood and urine as well as neuroimaging findings. No single one investigation in CSF can serve as a "selective screening" test. A growing awareness of these disorders is needed and should lead to increased and earlier diagnosis of patients through fewer rather than more lumbar punctures.
 ...
PMID:Cerebrospinal fluid investigations for neurometabolic disorders. 963 60

We observed a young patient with slight mental retardation, suffering from drug-resistant tonic-clonic seizures, who presented a status epilepticus (SE), in two separate periods when valproic acid (VPA) was added to the phenobarbital (PB) already being used in the patient's therapy. The VPA-induced SE was characterized by normal plasma levels of antiepileptic drugs (AEDs), normal ammonemia and normal liver function. The case we studied represents the first report on a VPA-induced SE. Furthermore the case confirms that VPA, as well as causing encephalopathy secondary to hyperammonemia, may also provoke a primary involvement of the central nervous system (CNS), specially when used in young epileptic, mentally retarded subjects. In an attempt to explain the paradoxical effect of VPA we hypothesise that the SE could be due to an increase in excitatory activity producing a consequent epileptogenic effect in those subjects with a predisposition for toxic reaction to VPA therapy due to congenital anomalies of neural networks.
 ...
PMID:Valproate-induced epileptic tonic status. 970 Aug 38

Magnetic resonance imaging (MRI) has enabled the identification of neuronal migration disorders in living subjects. This represents an important achievement in the diagnosis of patients with these anomalies. At least five affected families with coexistent subcortical laminar heterotopia and lissencephaly have been reported recently. This association suggests an X-linked pattern of inheritance. In the family that we report, the mother suffered from epilepsy and the oldest daughter from epilepsy and mental retardation. Both patients showed subcortical laminar heterotopia on MRI. The youngest son presented a severe encephalopathy with early onset seizures, and was found to show lissencephaly on MRI. The other two siblings, a boy and a girl, had no neurological abnormalities. The severity of these patients' clinical symptoms were clearly related to MRI findings.
 ...
PMID:X-linked subcortical laminar heterotopia and lissencephaly: a new family. 981 May 65

D-2-Hydroxyglutaric aciduria has been observed in patients with extremely variable clinical symptoms, creating doubt about the existence of a disease entity related to the biochemical finding. An international survey of patients with D-2-hydroxyglutaric aciduria was initiated to solve this issue. The clinical history, neuroimaging, and biochemical findings of 17 patients were studied. Ten of the patients had a severe early-infantile-onset encephalopathy characterized by epilepsy, hypotonia, cerebral visual failure, and little development. Five of these patients had a cardiomyopathy. In neuroimaging, all patients had a mild ventriculomegaly, often enlarged frontal subarachnoid spaces and subdural effusions, and always signs of delayed cerebral maturation. In all patients who underwent neuroimaging before 6 months, subependymal cysts over the head or corpus of the caudate nucleus were noted. Seven patients had a much milder and variable clinical picture, most often characterized by mental retardation, hypotonia, and macrocephaly, but sometimes no related clinical problems. Neuroimaging findings in 3 patients variably showed delayed cerebral maturation, ventriculomegaly, or subependymal cysts. Biochemical findings included elevations of D-2-hydroxyglutaric acid in urine, plasma, and cerebrospinal fluid in both groups. Cerebrospinal fluid gamma-aminobutyric acid was elevated in almost all patients investigated. Urinary citric acid cycle intermediates were variably elevated. The conclusion of the study is that D-2-hydroxyglutaric aciduria is a distinct neurometabolic disorder with at least two phenotypes.
 ...
PMID:D-2-Hydroxyglutaric aciduria: biochemical marker or clinical disease entity? 989 84

The Consensus Conference of the American College of Medical Genetics has established guidelines regarding the evaluation of patients with mental retardation (MR) [Curry et al., Am. J. Med. Genet. 72:468-477, 1997]. They emphasized the high diagnostic utility of cytogenetic studies and of neuroimaging in certain clinical settings. However, data on the diagnostic yield of these studies in well-characterized populations of individuals with MR are scant. Majnemer and Shevell [J. Pediatr. 127:193-199, 1995] attained a diagnostic yield of 63%. However, this study included only 60 patients and the classification included pathogenetic and causal groups. The Stella Maris Institute has evaluated systematically patients with developmental delay (DD)/MR and performed various laboratory studies and neuroimaging in almost all patients. We report a retrospective analysis of the diagnostic yield of 120 consecutive patients observed at our Institute during the first 6 months of 1996. There were 77 males and 43 females; 47 were mildly delayed (IQ 70-50), 31 were moderately delayed (IQ 50-35), and 42 were severely delayed (IQ 35-20). Diagnostic studies (history, physical examination, standard cytogenetics, fragile X testing, molecular studies, electroencephalography, electromyography, nerve conduction studies, neuroimaging, and metabolic screening tests) yielded a causal diagnosis in 50 (41.6%) and a pathogenetic diagnosis in 47 (39.2%) of the 120 patients. Causal categories included chromosomal abnormalities (14), Fra(X) syndromes (4), known MCA/MR syndromes (19), fetal environmental syndromes (1), neurometabolic (3) disorders, neurocutaneous (3) disorders, hypoxic-ischemic encephalopathy (3), other encephalopathies (1), and congenital bilateral perisylvian syndrome (2). Pathogenetic categories included idiopathic MCA/MR syndromes (35), epileptic syndromes (10), and isolated lissencephaly sequence (2). Diagnostic yield did not differ across categories and degree of DD. Our results, while confirming the diagnostic utility of cytogenetic/molecular genetic, and neuroimaging studies, suggest the usefulness of accurate electroencephalogram recordings, and stress the importance of a thorough physical examination. Referral to a university child neurology and psychiatry service, where a comprehensive assessment with a selected battery of investigations is possible, yields etiologic findings in a high percentage of DD/MR patients, with important implications for management, prognosis and recurrence risk estimate.
 ...
PMID:Diagnostic yield of the comprehensive assessment of developmental delay/mental retardation in an institute of child neuropsychiatry. 991 45

Two brothers are described who had juvenile-onset DHPR deficiency. Both were considered normal until six years of age when they developed a fluctuating and progressive encephalopathy combining mental retardation, epilepsy, pyramidal, cerebellar and extrapyramidal signs.
 ...
PMID:Juvenile form of dihydropteridine reductase deficiency in 2 Tunisian patients. 1002 53


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>