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

An A to G transition at nucleotide 3,243 in the tRNA(Leu(UUR)) gene of mitochondrial DNA (mtDNA) has been suggested to be the disease-related mutation for MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes). Recently, the same mutation has also been found in several pedigrees with maternally inherited diabetes mellitus and sensorineural deafness. We report here a family showing the association of deafness and diabetes mellitus, as the predominant clinical features, with this mutation. The mutation was detected by restriction-enzyme analysis of the relevant PCR-amplified segment of the mtDNA, in two generations. In this family, it is noteworthy that two members with the mutation had some symptoms of MELAS such as short stature, seizures and mental retardation and that one had no clinical symptoms though the mtDNA mutation was identified in his blood. The findings in this family demonstrate the diversity of clinical expression of the mtDNA mutation and suggest that a combination of sensorineural deafness and diabetes mellitus is only one typical presentation of the various phenotypic features caused by the 3,243 mutation.
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PMID:[Detection of a mutation in mitochondrial DNA in a family with sensorineural deafness and diabetes mellitus as the predominant clinical features]. 756 31

Epileptic seizures are frequently reported (4-32%) in autism. These values are higher than in the normal population of children and adolescents (0.5%). In the literature there is no uniform description of epilepsy in autism. We examined 106 patients with autistic disorder divided into three groups on the basis of presence or absence of EEG paroxysmal abnormalities (PA) and / or epilepsy including febrile convulsions (FG). Our patients presented an autistic syndrome unrelated to clear congenital or acquired encephalopathy. The prevalence of epilepsy and EEG PA was 23.6% and 18.9%, respectively. Significant differences between the three groups appeared for (i) familial antecedents for epilepsy / FC and neurologic and psychiatric diseases (P < 0.004), (ii) a different proportion between the three groups for mental retardation (P < 0.03), (iii) and EEG fast activity (P < 0.04). Our patients showed several types of epilepsy, including idiopathic forms with seizure onset after the age of 10 in 45% of cases. Seizures were mainly partial, not frequent and controllable by anti-epileptic drugs. PA were mostly focal and multifocal and in 45% of cases were typical of benign childhood partial epilepsy with centro-temporal spikes. The higher incidence of epilepsy and EEG PA is apparently not related to organic pre-, peri- and postnatal antecedents or cerebral lesions. On the contrary, genetic factors responsible for autism and epilepsy seem important in the genesis of these two disorders.
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PMID:EEG features and epilepsy in patients with autism. 857 26

We describe 2 sibs (brother and sister) with myopathy, sideroblastic anemia, lactic acidosis, mental retardation, microcephaly, high palate, high philtrum, distichiasis, and micrognathia. Very low levels of cytochromes a, b, and c were detected in the patients' muscle mitochondria. Deposition of iron within the mitochondria of bone marrow erythroblasts was observed on electron microscopy. Irregular and enlarged mitochondria with paracrystalline inclusions were also seen on electron microscopy of the patients' muscle specimen. Examination of DNA from the affected sibs showed no deletions in the mitochondrial DNA nor the mutations identified in the syndromes of mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS) or myoclonus, and epilepsy associated with rugged-red fibers (MERRF). Since the parents were first cousins and 2 of 6 sibs (male and female) were affected, we suggest that the syndrome expressed by our patients represents a previously unknown autosomal recessive disorder that includes mitochondrial myopathy, lactic acidosis, and sideroblastic anemia.
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PMID:Myopathy, lactic acidosis, and sideroblastic anemia: a new syndrome. 772 39

We examined the clinical and biochemical features of 27 cases with acute myoglobinuria who had been suspected of having metabolic myopathies. The systematic biochemical studies included the measurements of 13 glycolytic enzymes, mitochondrial respiratory chain enzymes, carnitine palmitoyltransferase (CPT) and 5 enzymes of fatty acid beta-oxidation. Enzyme defects were found in 9 patients using muscle biopsy specimens: phosphorylase deficiency in 3, CPT deficiency in 4 and phosphoglycerate kinase deficiency in 2. One patient was diagnosed as MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) with the histopathological examination and clinical data. A suspicion of beta-oxidation disorder was entertained in some patients of which the activities were about 50% of control means. However, no evidence to substantiate its significance as the enzyme defects was obtained from our data. Sixteen of 17 undiagnosed cases could be divided into two groups according to precipitating factors as follows: one had exercise as the factors and the other had infection. These groups also showed some differences in clinical features. In the infection group, myoglobinuria tended to progress more rapidly and was occasionally followed by acute renal failure. And some cases had additional associated conditions such as mental retardation or epilepsy. On the other hand, the exercise group had only myopathic symptoms. The difference in these clinical features between the two groups suggested that they had the different pathogenic mechanisms respectively.
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PMID:[Clinical and biochemical analysis of 27 patients with myoglobinuria of unknown causes]. 778 Dec 10

We performed magnetic resonance imaging (MRI) on the brain and neurologic examinations on 23 children after open heart surgery for congenital heart disease. Twenty children also had psychometric assessments. Examinations were performed at a mean age of 66 months (range, 26 to 180 months). Age at operation was less than 1 month in 43% and more than 6 months in 45%. Abnormal scans were found in 17 (74%) and showed diffuse findings consistent with hypoxic-ischemic encephalopathy, with or without areas of cortical infarction; focal cortical infarction alone; and (in one patient) callosal agenesis and abnormal neuronal migration. Normal IQ and neurologic examinations were found in all six of those who had a normal MRI, and five of six children with changes consistent with focal cortical infarction without diffuse change had a normal neurologic examination. Cerebral palsy and mental retardation was common in the group with diffuse abnormality (in eight of nine children), and this was more likely to occur in those who underwent prolonged (> 45 minutes) hypothermic circulatory arrest and operation during early infancy (P = .004). Focal cortical findings without diffuse changes were more likely in those who underwent open heart surgery without hypothermic circulatory arrest and were older than 6 months at operation, and these children were less likely to have frank neurodevelopmental sequelae. Thus, in our population, focal cortical lesions were common after open heart surgery, and, in addition, diffuse brain abnormality on MRI plus neurologic sequelae were common after prolonged hypothermic circulatory arrest.
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PMID:Long-term MRI changes in brain after pediatric open heart surgery. 782 31

We describe four Italian male infants with a novel clinical phenotype characterized by orthostatic acrocyanosis, relapsing petechiae, chronic diarrhea, progressive pyramidal signs, mental retardation, and brain magnetic resonance imaging abnormalities. The first symptoms appeared after the termination of breast-feeding and introduction of formula feeding. Marked persistent 2-ethylmalonic aciduria was associated with abnormal excretion of C4-C5(n-butyryl-, isobutyryl-, isovaleryl-, and 2-methylbutyryl-)acylglycines and acylcarnitines and with intermittent lactic acidosis. Short- and branched-chain plasma acylcarnitine levels were also elevated. 2-Ethylmalonic aciduria is generally regarded as being indicative of a defect in fatty acid oxidation. Extensive studies of cultured fibroblasts failed to reveal such a defect. The observation of intermittent urinary excretion of 2-ethylhydracrylic acid pointed to involvement of the isoleucine R pathway in ethylmalonate biosynthesis. This hypothesis was tentatively corroborated by the biochemical responses to an oral isoleucine challenge in two patients. However, fibroblast studies showed normal oxidation rates of (14C)isoleucine (ul), indicating that this is not a defect of isoleucine oxidation expressed in skin fibroblasts. In one of two patients tested, cytochrome c oxidase activity was partially reduced (45%) in cultured fibroblasts. This unique clinical and biochemical phenotype identifies a new metabolic encephalopathy of yet undetermined cause.
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PMID:A new syndrome with ethylmalonic aciduria and normal fatty acid oxidation in fibroblasts. 796 45

Trichothiodystrophy is characterized by sparse, short, sulfur-deficient hair. Numerous symptom complexes have been described in which the hair abnormality represents a constant feature. We report a boy with trichothiodystrophy, ichthyotic skin changes, onychodystrophy, chronic neutropenia, osteosclerosis, hypothyroidism, nystagmus, growth and mental retardation, and microcephaly, who developed a progressive encephalopathy with ataxia and optic atrophy at 2.5 years of age. In addition to a deficient cystine level identified on a hair sample, a disturbance in the composition of other amino acids was present. Although features were reminiscent of osteosclerosis, ichthyosis, brittle hair due to trichothiodystrophy, impaired intelligence, decreased fertility, and short stature (SIBIDS) and could represent a variant of this disorder, findings in our patient may reflect a new trichothiodystrophy symptom complex that carries a poor prognosis for survival beyond childhood.
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PMID:Trichothiodystrophy and associated anomalies: a variant of SIBIDS or new symptom complex? 834

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


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