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

A 19 year-old patient, second child of a non consanguinous marriage, was evaluated because of the patient progressive mental retardation and muscular weakness from infancy. Six maternal uncles non had died of unknown cause in the first year of life, and his mother had 3 spontaneous miscarriages; the two sisters of the patient were healthy. Clinical examination demonstrated a severe mental retardation, discrete proximal muscular weakness as well as universal areflexia. The muscular enzymes were elevated and the electrophysiologic study showed normal neurographic parameters and abundant generalized spontaneous activity with a mixed type contraction pattern. Histologic examination of the muscle was diagnosed as myopathy with atrophy of type I fibers and central nuclei and upon cranial nuclear magnetic resonance (NMR) images suggestive of perinatal hypoxic-ischemic encephalopathy were observed.
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PMID:[Centronuclear myopathy]. 844 42

In the 40 years from 1950 to 1990, lead epidemiology and public policy based on it made enormous strides. Exposure levels that caused concern in the medical and public health community fell from 80 to 10 micrograms/dL of blood. In the space of 20 years, beginning in 1970, first the surgeon general and then the CDC lowered the official "level of concern" from 50 or 60 to 10 micrograms/dL. The public health community has turned its attention from the prevention of poisoning that results in encephalopathy, mental retardation, and death to the reduction of exposure to avoid subtle neurobehavioral deficits that are detectable only in fairly large epidemiological studies. Numerous advances in technology and analysis have facilitated progress in lead epidemiology. In order to show that intellectual deficits were related to lead exposure rather than to such confounding variables as parental education, parental IQ, income, or parents' age at time of birth, researchers performed extensive regression analyses of fairly large sample populations, controlling for as many as 39 confounding variables. These analyses would have been virtually impossible but for the development of computer software programs that became available beginning in the late 1960s and early 1970s. Handling of large data bases, such as NHANES II, also required access to computer hardware and software not generally available earlier. The existence of the data depended on other technological innovations that made screening of large populations inexpensive and relatively simple. In 1973, erythrocyte protoporphyrin screening transformed testing for lead poisoning. With the advent of atomic absorption spectroscopy and rapid improvement in equipment for blood lead analysis, obtaining blood lead levels became less expensive and easier and produced more accurate results. Increasing attention both to preventing environmental contamination of samples and to controlling laboratory quality also improved the accuracy of data collected. Advances in screening and analytical technology made the mass screening of the 1970s possible--both the programs coordinated by the CDC and NHANES II. NHANES II showed the extent of the problem of lead exposure to be even greater than previously thought. It was estimated that in 1980 almost 2 percent of all children aged six months to five years had blood lead levels over the CDC level of concern of 30 micrograms/dL. More than 13 percent of black children had levels above 30 micrograms/dL. Lead was certainly the most widespread threat to child health in America. In 1985, when the CDC lowered the level of concern to 25 micrograms/dL, the population defined to be at risk tripled.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Round and round it goes: the epidemiology of childhood lead poisoning, 1950-1990. 845 Aug 21

A previously healthy 8-month-old girl developed exanthem subitum and acute encephalopathy with status epilepticus, quadriplegia and bilateral abducens nerve palsies. Human herpesvirus-6 DNA was found in the cerebrospinal fluid by the polymerase chain reaction at the acute stage. Cranial computed tomography showed low density areas in the thalami and in the cerebellar and abducens nuclei. The distribution of the lesions was consistent with acute necrotizing encephalopathy. As for the thalamic lesions, a T2 weighted magnetic resonance image on the 24th day of the illness demonstrated low signal intensity surrounded by high intensity; 99mTc-ECD SPECT showed hypoperfusion, which suggested irreversible tissue damage. The patient is now 1 year 6 months old and has spastic quadriparesis with mental retardation and abducens nerve palsies.
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PMID:Serial neuroimages of acute necrotizing encephalopathy associated with human herpesvirus 6 infection. 857 24

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.
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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.
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PMID:PEHO or PEHO-like syndrome? 872 64

Six of nine children born from first-cousin parents presented with the same clinical picture: non-progressive congenital encephalopathy with marked hypertonia resembling the stiff-baby syndrome, delayed milestones, mental deficiency and congenital deafness. Rare, usually reversible, episodes of sudden worsening of the neurological status, with progressive loss of consciousness and increase of hypertonia, occurred spontaneously or during febrile illnesses. During these periods, and sometimes on other occasions, transitory renal dysfunction was observed (nephrotic syndrome and/or tubular abnormalities). Death occurred before age 2 years in 4 patients; 2 are still alive (10 and 13 years old). Electrophysiological, biological and enzymatic investigations remained negative, particularly those concerning mitochondrial and peroxisomal metabolism. The only biochemical anomaly was a massive hyperkynureninuria, seen only during the periods of coma (up to 213 mumol/mmol creatinine; normal < 10) and after an intravenous protein loading test. This suggests an anomaly of tryptophan metabolism which has not been reported up to now.
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PMID:Congenital non-progressive encephalopathy and deafness with intermittent episodes of coma and hyperkynureninuria. 883 Jan 73

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.
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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.
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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.
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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.
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PMID:Cytomegalovirus infections of the nervous system. 945 Feb 26


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