Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mitochondrial encephalomyopathy is a hereditary syndrome showing impairment of muscle and the central nervous system. In this disorder, the following three syndromes have been identified on the basis of characteristic symptoms: Kearns-Sayre syndrome (KSS), mitochondrial encephalomyopathy with lactic acidosis, and stroke-like episodes (MELAS), and myotonic epilepsy with ragged-red fibers (MERRF). In this report, we describe a case of mitochondrial encephalomyopathy with renal disease. A 25-year-old man was referred to our hospital in May, 1992 for evaluation of long-standing proteinuria. He had a small stature, exotropia and no pretibial edema. No mental retardation was observed. Urinary protein excretion was 2.0 g/day and urine sugar was negative. Laboratory examination revealed a serum urea nitrogen 19 mg/dl, and a creatinine value of 1.5 mg/dl. Creatinine clearance was 45.8 ml/min. His serum and spinal fluid lactate value were elevated. Biopsied muscle showed an absence of ragged-red fibers, and the presence of an A-to-G point mutation at nucleotide pari 3243 in the mitochondrial tRNA(Leu(UUR)) in peripheral blood leucocytes. He was thought to have MELAS. On the renal biopsy specimens, light microscopic examinations showed minor glomerular abnormalities with two glomerular collapses and tubulo-interstitial damage. Electron microscopic examinations showed partial thickening of the glomerular basement membrane. We report here this rare case of MELAS with renal disease, and also review seventeen cases of mitochondrial encephalopathy associated with renal disease. The existence of a relationship between mitochondrial disorder and renal damage remains obscure.
 ...
PMID:[A case of mitochondrial encephalomyopathy (MELAS)]. 871 14

PEHO syndrome is a rare progressive infantile encephalopathy, with variable age of onset of hypotonia, convulsions, mental retardation, oedema, and optic atrophy. Neuroimaging shows cerebellar and brainstem atrophy in most instances. A PEHO-like syndrome has been described in which those affected do not have the typical changes on neuroimaging. We report four new cases, two isolated cases and two sisters, who might be part of the PEHO-like syndrome.
 ...
PMID:PEHO or PEHO-like syndrome? 872 64

Using magnetic resonance imaging (MRI), we studied the myelination of the brains of 8 patients with West syndrome. All cases were symptomatic, 2 having severe asphyxia, 1 lissencephaly, 1 Leigh encephalopathy, 2 tuberous sclerosis, 1 multiple anomalies and 1 microcephaly. Myelination of the pons, cerebellum, thalamus, internal capsules, optic radiation, centrum semiovale and cerebral white matter was separately assessed. The 2 cases with tuberous sclerosis exhibited normal myelination patterns, although asymmetry of the cerebral white matter was noted. These cases had a moderate degree of mental retardation and persistent seizures. The other 6 cases exhibited a marked delay of myelination throughout the central nervous system except for the midbrain. These cases had severe psychomotor retardation and persistent seizures. Although the difference in the outcome may simply reflect the different etiological disorders, these results suggest that the myelination pattern is related to the psychomotor retardation but not to the severity of the seizures in West syndrome. Atrophy of the corpus callosum developed during ACTH therapy and disappeared after the therapy. It was thus suggested that the callosal atrophy caused by the ACTH therapy was reversible.
 ...
PMID:An MRI study of the myelination pattern in West syndrome. 883 97

Seizure-inducing effects can be observed in the treatment of epileptic patients with antiepileptic drugs (AED). This may be a paradoxical reaction (for example the increase of complex focal seizures due to carbamazepine, vigabatrin or phenytoin treatment) or a result of AED-induced encephalopathy (commonly induced by valproate in patients with complex focal seizures). A seizure increase during intoxication with AED is a rare phenomenon, thus, it is not directly related to this condition. An incorrect choice of drugs in the treatment of an epileptic syndrome or seizure type may provoke seizures (as for example the provocation of absences due to carbamazepine or phenytoin). The possible seizure-inducing effect of AEDs has to be differentiated from seizure occurrence due to the natural course of epilepsy. This may be especially difficult in patients suffering from West syndrome or Lennox-Gastaut syndrome, in whom seizure frequency may vary even without medication. However, especially in these patients, drug-induced worsening of seizure manifestation is often observed. In general, a seizure-inducing effect of antiepileptic drugs has to be considered when a seizure increase is observed soon after the initiation of therapy, when a stepwise increase of the dosage is followed by a further increase of seizures, a decrease of seizures is seen with tapering of the dosage and a renewed increase of seizures can be observed after this therapy has been reestablished. Finally, one knows that the clinical condition of encephalopathy due to valproate or carbamazepine is accompanied by seizure increase. In spite of these clinical aspects, the underlying mechanisms of seizure increase mostly remain unclear. From animal experiments it is obvious that especially carbamazepine and phenytoin may provoke generalized seizures as absences or myoclonic seizures. A seizure increase during vigabatrin therapy has been attributed to the increase of the cerebral amount of gamma-amino butyric acid, which is known to possibly exhibit inhibitory or excitatory neuronal effects. The occurrence of tonic seizures in patients with Lennox-Gastaut syndrome has been attributed to the sedative effect of the drugs; however, this conclusion is controversial. From a clinical point of view, one should consider young age of the patient, mental retardation, antiepileptic polytherapy, high frequency of seizures or prominent epileptic activity in the electroencephalogram previous to medication as risk factors for a possible seizure-inducing effect of antiepileptic drugs.
 ...
PMID:Seizure-inducing effects of antiepileptic drugs: a review. 901 23

West syndrome is a strictly age-limited encephalopathy of early infancy with unknown pathogenesis. It is often progressive, leading to mental retardation. Neurotrophic factors are important for the regulation of neuronal survival and differentiation, and their expression is influenced by hormones. Levels of beta-nerve growth factor in the cerebrospinal fluid were examined by two-site enzyme-linked immunosorbent assay method. Human antigen was used as a standard. We present data on largely normal levels of nerve growth factor in the cerebrospinal fluid of infants with cryptogenic etiology, but low or negligible levels in infants with symptomatic etiology, and very high levels in infants with symptomatic postinfectious etiology. Treatment with ACTH led to a greater increase in patients with a good response than in those with a poor response. Low nerve growth factor in patients with symptomatic infantile spasms possibly reflects massive neuronal death. The regression seen in these infants and their poor response to ACTH therapy may be due in part to lack of growth factors supporting neuron survival. This study, previously only demonstrated in animal models, is the first to depict nerve growth factor gene activity in humans as modulated by steroids.
 ...
PMID:West syndrome: cerebrospinal fluid nerve growth factor and effect of ACTH. 939 Jun 98

Experimental evidence and pathological observation indicate that human cytomegalovirus (HCMV) has a tropism for cells of the nervous system, including both neuronal and glial cells. As demonstrated in animal models, after a viremic phase, the virus may reach the brain, where it may cause mild infection or severe encephalitis. The nervous system is one of the principal target organs in congenital HCMV infections and in HCMV-infected AIDS patients. In the former case, mortality is high and neurological sequelae, such as mental retardation, are frequent; in the latter it may lead to a progressively wasting encephalopathy and death within a few weeks. The diagnosis of the nervous system manifestations due to HCMV can now rely upon the detection of HCMV DNA in cerebrospinal fluid by means of polymerase chain reaction. However, the current antiviral treatments of these complications are of limited effect.
 ...
PMID:Cytomegalovirus infections of the nervous system. 945 Feb 26

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


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