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)

We describe three families with X-linked recessive Charcot-Marie-Tooth (CMT) neuropathies. The disease phenotype in family 1 was characterized by infantile onset, weakness of lower legs, areflexia, pes cavus, and mental retardation (2 of 5 patients). The disease phenotype in families 2 and 3 was characterized by late onset, distal weakness, and normal intelligence. Hereditary spastic paraparesis was also present in the CMT patients of family 2. Thirty X-linked DNA markers were used for linkage studies. A maximum lod score of +3.48 was obtained by multipoint linkage analysis for the DXS16 locus mapped at Xp22.2 in family 1. In families 2 and 3, there was suggestion of linkage of Xq26 markers; the peak multipoint lod score for these 2 CMT families was 1.81, at DXS144. These results were suggestive of heterogeneity. The joint analysis including both regions (Xp22.2 and Xq26) provided evidence against homogeneity (chi 2 = 9.12, P less than 0.005).
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PMID:X-linked recessive Charcot-Marie-Tooth neuropathy: clinical and genetic study. 155 86

Interstitial deletion of the short arm of chromosome 17 was detected in three patients. They all had a similar phenotype with mental retardation, behavioural problems, facial dysmorphism, brachycephaly, a broad face with a flat midface, and short and broad hands. All three cases were ascertained over a six month period by two neuropaediatricians aware of this specific anomaly, which suggests that this microdeletion is not particularly rare. Comparison of the clinical and cytogenetic findings in a total of 24 patients allows a new contiguous gene syndrome to be defined that only high resolution analysis can detect. In two cases, molecular analysis confirmed the cytogenetic results. The Charcot-Marie-Tooth type Ia gene has recently been localised to the 17p11.2 sub-band.
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PMID:Smith-Magenis syndrome: a new contiguous gene syndrome. Report of three new cases. 195 64

We report on a family with an apparently X-linked neuromuscular disease. Electrophysiologic tests and electron microscopic studies are consistent with the diagnosis of hereditary motor sensory neuropathy type II (HMSN-II), one form of Charcot-Marie-Tooth disease. The manner of inheritance, the observation that males are severely affected from infancy, and the frequent association of deafness and/or mental retardation with the neuromuscular disorder are not usual for HMSN-II and suggest that this family may have a previously undescribed genetic disorder. The peripheral neuropathy did not appear to be linked to the Xg blood group. Minor abnormalities of sensory nerve conduction, electromyography, and hearing were separately identified in female relatives in this family, but were not consistent enough to be useful in the identification of carriers for this gene.
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PMID:X-linked motor-sensory neuropathy type-II with deafness and mental retardation: a new disorder. 385 85

We report the clinical and electrophysiologic data on five subjects from two families with severe sensory and autonomic neuropathy who also exhibited peroneal muscular atrophy with the electrophysiologic features of an axonopathy, congenital cataracts, mental retardation, and skin lesions. One patient had hearing loss. Autosomal recessive inheritance was probable in both families.
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PMID:Hereditary sensory and autonomic neuropathy with cataracts, mental retardation, and skin lesions: five cases. 761 5

Neural cell adhesion proteins play important roles in neural development and are involved in various neurological diseases. P0, a major protein in mammalian peripheral myelin, mediates not only homophilic cell adhesion but also neurite outgrowth. The P0 glycopeptide inhibits the cell adhesion, but not the neurite outgrowth. Several point mutations of the P0 gene in human chromosome 1q22-23 were found in Charcot-Marie-Tooth (CMT) disease type 1B and Dejerine-Sottas (DS) disease. PASII/PMP22 and connexin 32 were also reported as target proteins of similar hereditary neuropathies. L1 is a large multifunctional protein involved in cell adhesion, neurite outgrowth, fasciculation, and neuronal cell migration. A short isoform of L1 localizes in non-neuronal cells in contrast to the complete L1 exclusively expressed in neurons. Recently various L1 mutations have been reported in X-linked hydrocephalus, MASA syndrome with mental retardation and spastic paraplegia type 1. Further studies on the mutations and disease phenotypes are important and interesting.
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PMID:Neural cell adhesion proteins and neurological diseases. 770 5

Over the past few years, molecular neurogenetics has developed into one of the most promising and active research fields. The new discipline applies modern molecular genetic techniques to the investigation of classical neurological disorders. In the following article, a definition of neurogenetic disease is introduced, the molecular basis of four groups of neurogenetic disorders is described and recent diagnostic developments are presented. The first group of diseases is caused by trinucleotide expansions. "Expanding" trinucleotide repeats were not known to occur in any species until about three years ago. Today, disorders such as Huntington's disease, spinocerebellar ataxia type 1, fragile X mental retardation, spinobulbar muscular atrophy and myotonic dystrophy are all known to be caused by the expansion of trinucleotides. The second group is characterized by chromosomal deletions or uniparental disomies. Lissencephaly and the Miller-Dieker syndrome, Prader-Willi and Angelman syndromes and Duchenne and Becker muscular dystrophies belong to this category. The third group includes those neurogenetic disorders that are mainly caused by point mutations such as the X-linked leukodystrophies, including Pelizaeus-Merzbacher disease and adrenoleukodystrophy, Charcot-Marie-Tooth syndrome type 1, familial forms of amyotrophic lateral sclerosis, several types of craniosynostoses and some CNS tumor syndromes. Finally, Alzheimer's and Parkinson's disease are discussed as representatives of group four, i.e. genetically heterogeneous neurological disorders.
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PMID:Molecular basis and diagnosis of neurogenetic disorders. 796 63

Charcot-Marie-Tooth (CMT) disease is the commonest inherited peripheral neuropathy. The clinical study of 45 patients with CMT is presented. They were derived from Antonio Pedro Hospital of Universidade Federal Fluminense in Niteroi, RJ, Brazil. Such patients could be divided by the motor conduction velocity in two types: a demyelinating form or type I (11 cases) and an axonal form or type II (34 cases). The disease was inherited as an autosomal dominant trait in 23 patients and as an autosomal recessive trait in 7 cases. In 15 patients the disorder was sporadic. The age of onset was in most of our cases before the 20 years. All of them had distal weakness in lower limbs. 38.2% had also distal weakness in upper limbs. 80% had distal wasting of the lower limbs and 50% had distal wasting of upper limbs. The tendon reflexes were absent in 64% in lower limbs and in 28% in upper limbs. The sensitive impairment in the distal regions of the extremities was mild in most patients. We found enlargement of peripheral nerves in 7 patients of type I. Pes cavus was present in 21 cases and scoliosis in 7. We found postural tremor of hands in 6 patients. In 9 cases there were rare features as mental retardation, trigeminal nevralgia, optic atrophy, deafness and calf enlargement. In most of our cases the clinical course was very slow progressive. A greater severity was seen in our sporadic cases.
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PMID:[Charcot-Marie-Tooth disease. Clinical study in 45 patients]. 858 9

M6 is a neuronal membrane glycoprotein that may have an important role in neural development. This molecule was initially defined by a monoclonal antibody that affected the survival of cultured cerebellar neurons and the outgrowth of neurites. The nature of the antigen was discovered by expression cDNA cloning using this monoclonal antibody. Two distinct murine M6 cDNAs (designated M6a and M6b) whose deduced amino acid sequences were remarkably similar to that of the myelin proteolipid protein were previously isolated. We have isolated partial human cDNA and genomic clones encoding M6a and M6b and have characterized them by restriction mapping, Southern hybridization with cDNA probes, and sequence analysis. We have localized these genes within the human genome by FISH (fluorescence in situ hybridization). The human M6a gene is located at 4q34, and the M6b gene is located at Xp22.2. A number of human neurological disorders have been mapped to the Xp22 region, including Aicardi syndrome (MIM 304050), Rett syndrome (MIM 312750), X-linked Charcot-Marie-Tooth neuropathy (MIM 302801), and X-linked mental retardation syndromes (MRX1, MIM 309530). This raises the possibility that a defect in the M6b gene is responsible for one of these neurological disorders.
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PMID:Chromosomal mapping of the human M6 genes. 866 Oct 15

Familial polyneuropathy mimicking Charcot-Marie-Tooth disease associated with parkinsonism and dementia has been reported in literature. We present with similar peroneal muscular atrophy, rigidity of upper extremities, severe peripheral neuropathy, mental retardation and diabetes mellitus. The patient, a 42-year-old man, developed progressive muscle weakness, mental retardation and difficulty in walking in childhood. Because of his pes cavus, he had three surgical operations. At the age of 20 years, he developed distal muscular atrophy of lower limbs. On neurological examination, all limb muscles were atrophic, especially in lower one third of the thigh. Rigidity was noted in the upper extremities. Deep tendon reflexes were hyperactive in the upper and diminished in the lower extremities. Muscle CT revealed low density areas in all the muscles examined, specially in the gastrocnemius and anterior tibial muscles. Needle EMG showed neurogenic change in the forearm, but not in the lower limbs, because of no voluntary contractions obtained due to severe muscle atrophy. Marked slowing of motor conduction velocity with muscle action potentials of very low amplitude was found in the ulnar nerve. Muscle action potentials were not elicited in the median and peroneal nerves. Sensory action potentials were not elicited from the median, ulnar and sural nerves. These findings were consistent with axonal polyneuropathy. In the sural nerve biopsy, the densities of myelinated fibers were markedly decreased. However, unmyelinated fiber densities were relatively preserved. Onion bulb formation was not found. This patient may be classified into hereditary motor-sensory neuropathy (HMSN) type II based on the clinical findings delayed nerve conduction velocities and axonal degeneration in the sural nerve. He has also diabetes mellitus. CT of the brain revealed nothing particular. He is one of members with familial Parkinson's disease (PD) developed in Sagamihara. Peroneal muscular atrophies are not necessarily associated with PD, though it has been occasionally complicated in various neuro-degenerative diseases including parkinsonism. We are now following the patient to detect the symptom of Parkinson's disease for early treatment.
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PMID:[An unusual case of peroneal muscular atrophy with rigidity, polyneuropathy, mental retardation, and diabetes mellitus developed in familial Parkinson's disease]. 866 30

We describe a de novo dup 17p11 in a boy with Alport syndrome, mild mental retardation, and minor anomalies. Combining classical and molecular cytogenetics analyses, the karyotype was defined as 46,XY.ish dup (17)(p11.2p11.2)(D17S29++,D17S379+). Alport syndrome is associated with mutations in the type IV alpha chain collagen gene, however, no known collagen-related gene is currently mapped to 17p11. Duplications involving 17p11.2 have been reported in Charcot-Marie-Tooth disease, Dejerine-Sottas syndrome, and in a few sporadic patients with mental retardation and minor anomalies, however, no significant clinical similarity was found among these cases and the propositus. Further studies may clarify the meaning of the association between Alport syndrome and duplications of DNA sequences mapped at 17p11.2.
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PMID:A dup(17)(p11.2p11.2) detected by fluorescence in situ hybridization in a boy with Alport syndrome. 993 86


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