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)

Neurofibromatosis (NF), also known as von Recklinghausen's disease, is a prevalent genetic disorder--as common as cystic fibrosis and Down's syndrome and twice as prevalent as muscular dystrophy; it occurs in approximately one of 3000 live births. NF often involves the eyes and visual pathways; many NF patients first present early in life because of ocular complaints. But, because mental retardation can be a complication of the disease, such patients are difficult to examine and, as a result, the disease is sometimes not recognized. The purpose of this paper is to provide an overview of the condition along with a case report of an eight year old child with NF.
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PMID:Clinical review of neurofibromatosis. 211 55

Neurologic and cognitive function in neurofibromatosis type 1 (NF1) were assessed in a controlled pilot study of 13 pairs of siblings aged 6 to 27 years. One subject in each pair was affected with NF1, and the other, the control subject, was unaffected. Subjects with evidence of focal central nervous system disease were excluded. The 13 subjects with NF1 had no excess of mental retardation, attention-deficit disorder, or specific learning disorders (using Wilcoxon's Signed Rank Test and McNemar's Test for Symmetry). These subjects, however, had significantly higher scores for subtle neurologic abnormalities (21 vs 6) and significantly lower full-scale IQ scores (94 vs 105) than their unaffected siblings. The IQ scores of the affected subjects were not clustered at the lower end of the scale but showed a slight downward shift in distribution compared with those of their siblings. In addition, a visual-spatial orientation deficit was present in eight of nine affected subjects so evaluated. The findings suggest that subjects with NF1 have a widespread alteration of the brain during development that manifests as one or more specific types of neuropsychologic deficits.
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PMID:Neurofibromatosis type 1 (Recklinghausen's disease). Neurologic and cognitive assessment with sibling controls. 250 Aug 44

Areas of increased signal seen on magnetic resonance imaging (MRI) of the brain are frequently present in neurofibromatosis and are considered possible areas of dysplasia or heterotopias. Since Rosman and Pearce [Brain 1967; 90:829-838] have shown that neuronal heterotopias in deep cerebral white matter are associated with mental retardation in neurofibromatosis type 1 (NF-1), we hypothesized that these areas of increased signal seen on MRI should be associated with learning difficulties or incoordination in children with NF-1. Using MRI, we studied 31 children with NF-1 and attempted to correlate the presence of areas of increased signal with learning difficulties or incoordination. We found no association. This suggests that either these areas of increased signal are heterotopias which are not associated with learning difficulties or incoordination, or these areas of increased signal are not heterotopias and are not relevant to the study of learning problems or incoordination in children with NF-1.
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PMID:Magnetic resonance imaging evaluation of learning difficulties and incoordination in neurofibromatosis. 251 20

Hereditary gastrointestinal polyposis syndromes can be divided into adenomatous and hamartomatous types. Familial adenomatous polyposis coli (FAPC) is the prototype adenomatous polyposis syndrome and is defined by the autosomal dominant transmission of multiple (more than 100) colorectal adenomas. Virtually all affected patients develop colorectal carcinoma if untreated. Adenomas may develop also in the stomach and small bowel in FAPC patients, but the incidence of carcinoma in these sites is low. A variety of extracolonic manifestations has been reported in FAPC, with the name Gardner's syndrome applied to kindreds with osteomas of the skull and mandible, multiple epidermal cysts, and other skin and soft-tissue lesions. In Turcot's syndrome, brain tumors are present. The distinction between Gardner's and Turcot's syndromes and classical FAPC has become blurred because of marked overlap between them; some authorities consider them to be varying manifestations of a single genetic defect. The hamartomatous polyposes include Peutz-Jeghers syndrome, familial juvenile polyposis, Cowden's disease, intestinal ganglioneuromatosis, and the Ruvalcaba-Myrhe-Smith syndrome. The incidence of gastrointestinal cancer in patients with Peutz-Jeghers syndrome and familial juvenile polyposis exceeds that in the normal population, but is relatively low. In Cowden's disease, the gastrointestinal tract may be the site of multiple hamartomas, but there is no associated increase in the incidence of gastrointestinal cancers; instead, there is an increased incidence of carcinoma of the breast and thyroid. Intestinal ganglioneuromatosis occurs in von Recklinghausen's disease, in association with multiple endocrine neoplasia, type 2b, or as an isolated abnormality. Patients with ganglioneuromatosis do not appear to have an increased risk of developing gastrointestinal cancer. Ruvalcaba-Myrhe-Smith syndrome comprises macrocephaly, mental deficiency, an unusual craniofacial appearance, hamartomatous intestinal polyposis, and pigmented macules on the penis. No increased risk of developing cancer has been identified in the few reported cases.
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PMID:Hereditary gastrointestinal polyposis syndromes. 302 15

Otorhinolaryngological manifestations of 13 patients with von Recklinghausen's disease appearing at Lagos University Teaching Hospital over a five-year period have been studied. Among patients with ENT manifestations of the disease, the most common general features exhibited were cutaneous neurofibromas (100 per cent), headache (69.23 per cent) and pruritus (46.15 per cent). But the head and neck findings included external meatal canal stenosis (30.77 per cent), conductive deafness (30.77 per cent), nasal discharge (30.77 per cent), cranial nerve involvement (30.77 per cent) and disfigurement of the soft tissues of the face (30.77 per cent). Involvement of pinna (23.31 per cent), rhinolalia aperta (15.38 per cent), mental retardation (15.38 per cent) and pharyngeal swelling (7.69 per cent) also featured. Clinically detectable bilateral acoustic neurofibromas in adults or astrocytomas in children were not found in this series. Involvement of the frontoparietal bone (7.65 per cent) presented with skull bossing which had to be differentiated from that due to sickle cell disease in the African. There was also a singular case of phrenic nerve involvement. However, malignancy occurred in one (7.69 per cent) of these patients. Thus, it is important always to follow-up these patients closely so as to detect malignant transformation in time.
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PMID:Otorhinolaryngological manifestations of von Recklinghausen's disease in Nigerians. 308 May 40

A case of neurofibromatosis with varied clinical symptoms due to parental consanguinity is reported. The patient presented the following manifestations: mental retardation, curved tibias, kyphoscoliosis, basillary impression with pyramidal syndrome and parkinsonism, subluxation of the lenses, bilateral blindness, and hypogonadism. Subluxation of the lenses and hypogonadism deserve special mention because of the rarity of their presentation in this disease. The hypogonadism was of the hypogonadotrophic type without evidence of pituitary or gonadal tumor. The possible causes of endocrine dysfunction in neurofibromatosis are discussed. The more likely hypothesis explains endocrine dysfunction on the basis of an elongation of the pituitary stem; if such abnormality was caused by gliosis of the optic chiasma, an explanation would be apparent for the bilateral blindness presented by our patient since infancy. The alterations of the nervous, endocrine, and osteoarticular systems, and the ocular manifestations that can be present in von Recklinghausen's disease are also reviewed.
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PMID:[Hypogonadism, basillary impression, subluxation of the lenses, and other clinical manifestations in a case of neurofibromatosis (author's transl)]. 678 93

Neurofibromatosis type 1 (NF1) or von Recklinghausen neurofibomatosis, is a common heritable neurocutaneous disorder. This disorder appears to affect all races, with a prevalence estimated to be 1 in 3000. Approximately half of all cases of NF1 represent new mutations. The characteristics of NF1, which include cafe-au-lait spots, neurofibromas, Lisch nodules, optic glioma, osseous lesions, macrocephaly, short stature and mental retardation suggest that the genetic lesion affects the proper development of multiple organ systems. Within the past few years, the gene causing NF1 has been identified and the protein encoded by this gene, neurofibromin, has been the subject of detailed investigation. The NF1 gene spans over 350 kb of genomic DNA and encodes a protein product of 2818 amino acids. Neurofibromin is expressed in many different tissues. It is now known that one role of neurofibromin is as a GTPase activating protein (GAP), very likely in the same pathway of signal transduction as ras. Absence of neurofibromin in mice homozygously mutant for the NF1 gene results in profound developmental abnormalities. In mice that are heterozygous for NF1, an accelerated onset of tumor formation is observed. Combined with studies of tumors from NF1 patients showing homozygous deletions in the NF1 gene, these data suggest a role for NF1 as a "tumor suppressor". Evidence suggesting other roles played by neurofibromin, in control of proliferation in some situations and differentiation in others, is gradually bringing the previously hazy picture of this genetic disorder into sharper focus.
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PMID:Neurofibromatosis type 1: pathology, clinical features and molecular genetics. 767 Jun 56

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder characterized by marked variation in clinical severity. To investigate the contribution to variability by genes either contiguous to or contained within the NF1 gene, we screened six NF1 patients with mild facial dysmorphology, mental retardation, and/or learning disabilities, for DNA rearrangement of the NF1 region. Five of the six patients had NF1 gene deletions on the basis of quantitative densitometry, locus hemizygosity, and analysis of somatic cell hybrid lines. Analyses of hybrid lines carrying each of the patient's chromosomes 17, with 15 regional DNA markers, demonstrated that each of the five patients carried a deletion > 700 kb in size. Minimally, each of the deletions involved the entire 350-kb NF1 gene; the three genes--EVI2A, EVI2B, and OMG--that are contained within an NF1 intron; and considerable flanking DNA. For four of the patients, the deletions mapped to the same interval; the deletion in the fifth patient was larger, extending farther in both directions. The remaining NF1 allele presumably produced functional neurofibromin; no gene rearrangements were detected, and RNA-PCR demonstrated that it was transcribed. These data provide compelling evidence that the NF1 disorder results from haploid insufficiency of neurofibromin. Of the three documented de novo deletion cases, two involved the paternal NF1 allele and one the maternal allele. The parental origin of the single remaining expressed NF1 allele had no dramatic effect on patient phenotype. The deletion patients exhibited a variable number of physical anomalies that were not correlated with the extent of their deletion. All five patients with deletions were remarkable for exhibiting a large number of neurofibromas for their age, suggesting that deletion of an unknown gene in the NF1 region may affect tumor initiation or development.
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PMID:Deletions spanning the neurofibromatosis 1 gene: identification and phenotype of five patients. 811 12

Multiple lentigines (LEOPARD) syndrome has been delineated as an autosomal dominant disorder with lentigines, cardiac abnormalities, variable mental retardation, and typical craniofacial features as the most characteristic findings. LEOPARD syndrome shows a great clinical overlap with neurofibromatosis type 1 (NF1). In this report we describe a de novo missense mutation (M 1035R) in exon 18 of the NF1 gene in a young woman with a prior diagnosis of LEOPARD syndrome. We hypothesize that some patients now diagnosed with LEOPARD syndrome have in fact a mutation in the NF1 gene, whereas in other patients with LEOPARD syndrome, a different gene might be involved.
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PMID:Neurofibromatosis type I gene mutation in a patient with features of LEOPARD syndrome. 880 36

We report on a rare patient screened as a putative carrier of a contiguous gene syndrome on the basis of a complex phenotype characterized by sporadic neurofibromatosis type 1 (NF1), dysmorphism, mental retardation and severe skeletal anomalies. A cytogenetically visible 17q11.2 deletion was detected in the patient's karyotype by high-resolution banding and confirmed by fluorescence in situ hybridization with yeast artificial chromosomes targeting the NF1 region. Analysis of the segregation from parents to proband of 13 polymorphic DNA markers, either contiguous or contained within the NF1 gene, showed that the patient is hemizygous at sites within the NF1 gene-the AAAT-Alu repeat in the 5' region of intron 27b, the CA/GT microsatellite in the 3' region of intron 27b, and the CA/GT microsatellite in intron 38- and at the extragenic D17S798 locus, distal to the 3' end of NF1. The patient may be an important resource in the identification of genes downstream of NF1 that may contribute to some of his extra-NF1 clinical signs.
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PMID:Characterization of a cytogenetic 17q11.2 deletion in an NF1 patient with a contiguous gene syndrome. 893 93


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