Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028738 (nystagmus)
 7,431 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pelizaeus-Merzbacher disease (PMD) is a rare dysmyelinating disorder caused by mutations in the proteolipid protein 1 (PLP1) gene. PMD is generally classified according to its clinical or pathological features into classical or connatal forms. We describe here a 19-year-old male with classical form PMD who presented with stridor and nystagmus in early infancy and whose psychomotor development has been severely delayed. Brain magnetic resonance imaging revealed white matter abnormalities typical of PMD. Direct sequencing of the PLP1 gene identified two nucleotide substitutions. One was a C-to-T transition at -31 in the 5'-flanking region of exon 1; the other was a novel point mutation, T-to-C transition in exon 4, which led to substitution of cysteine for arginine at residue 184. Because Cys184 forms a disulphide bridge with Cys228, the Cys184Arg mutation probably removes the bridge and changes the tertiary structure of PLP protein. A defective disulfide bond in PLP protein could be important in the pathogenesis of PMD.
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PMID:A novel proteolipid protein 1 gene mutation causing classical type Pelizaeus-Merzbacher disease. 2117 54

Pelizaeus-Merzbacher disease (PMD) is a white matter dystrophy of the brain. Most children with PMD require comprehensive nursing care. Their speech and language abilities are poor or absent. Therefore, evaluating hearing ability is difficult in children with PMD. We have followed up two patients with PMD since early childhood. Patient 1 is an 11-year-old boy, and patient 2 is a 15-year-old adolescent boy in whom horizontal nystagmus was recognized after birth. Magnetic resonance imaging showed diffuse dysmyelination of the cerebral white matter. Auditory brainstem response recordings showed only waves I and II and the absence of all subsequent components. However, conditioned orientation reflex audiometry showed a threshold of 20-30 dB. Both patients can converse orally and have auditory perception and speech abilities better than those of most patients with PMD in the literature. We report on the development of their hearing and speech abilities.
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PMID:Development of speech and hearing of two children with Pelizaeus-Merzbacher disease presenting only waves I and II of the auditory brainstem response. 2226 26

Pelizaeus-Merzbacher disease (PMD; MIM#312080) is a rare X-linked leukodystrophy presenting with motor developmental delay associated with spasticity and nystagmus. PMD is mainly caused by abnormalities in the proteolipid protein 1 gene (PLP1), most frequently due to duplications of chromosomal segments including PLP1. In this study, a 9-year-old male patient manifesting severe developmental delay and spasticity was analyzed for PLP1 alteration, and triplication of PLP1 was identified. Further examination revealed an underlying genomic organization, duplication-inverted triplication-duplication (DUP-TRP/INV-DUP), in which a triplicated segment was nested between 2 junctions. One of the 2 junctions was caused by inverted homologous regions, and the other was caused by non-homologous end-joining. PMD patients with PLP1 duplications usually show milder-classical forms of the disease compared with patients with PLP1 missense mutations manifesting severe connatal forms. The present patient showed severe phenotypic features that represent an intermediate form of PMD between classical and connatal forms. This is the first report of a patient with PLP1 triplication caused by a DUP-TRP/INV-DUP structure. This study adds additional evidence about the consequences of PLP1 triplication.
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PMID:Pelizaeus-Merzbacher disease caused by a duplication-inverted triplication-duplication in chromosomal segments including the PLP1 region. 2249 Apr 26

Homozygous or compound heterozygous mutations in the GJC2 gene, encoding the gap junction protein connexin47 (Cx47), cause the autosomal recessive hypomyelinating Pelizaeus-Merzbacher-like disease (PMLD1, MIM# 608804). Although clinical and neuroradiological findings resemble those of the classic Pelizaeus-Merzbacher disease, PMLD patients usually show a greater level of cognitive and motor functions. Unpredictably a homozygous missense GJC2 mutation (p.Glu260Lys) was found in a patient presenting with a very severe clinical picture characterised by congenital nystagmus and severe neurological impairment. Also magnetic resonance imaging was unusually severe, showing an abnormal supra- and infratentorial white matter involvement extending to the spinal cord. The novel p.Glu260Lys (c.778G>A) mutation, occurring in a highly conserved motif (SRPTEK) of the Cx47 extracellular loop-2 domain, was predicted, by modelling analysis, to break a 'salt bridge network', crucial for a proper connexin-connexin interaction to form a connexon, thus hampering the correct formation of the connexon pore. The same structural analysis, extended to the previously reported missense mutations, predicted that most changes were expected to have less severe impact on protein functions, correlating with the mild PMLD1 form of the patients. Our study expands the spectrum of PMLD1 and provides evidence that the extremely severe clinical and neuroradiological PMLD1 form of our patient likely correlates with the predicted impairment of gap junction channel assembly resulting from the detrimental effect of the new p.Glu260Lys mutant allele on Cx47 protein.
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PMID:Expanded spectrum of Pelizaeus-Merzbacher-like disease: literature revision and description of a novel GJC2 mutation in an unusually severe form. 2266 16

Pelizaeus-Merzbacher disease (PMD) is a rare X-linked recessive disorder characterized by nystagmus, impaired motor development, ataxia, and progressive spasticity. Genetically defective or altered levels of proteolipid protein (PLP1) or gap-junction alpha protein 12 gene have been found to be a common cause. Here we report on two large Han Chinese families affected with this disease. The probands of both families had produced sons featuring cerebral palsy that had never been correctly diagnosed. PMD was suspected after careful analysis of family history and clinical features. Three rounds of molecular testing, including RT-PCR, genetics linkage and SRY sequence analyses, in combination with fetal ultrasound and magnetic resonance imaging, confirmed the diagnosis. In Family 1, in addition to two patients, three carriers were identified, including one who was not yet married. Genetic testing indicated that a fetus did not have the disease. A healthy girl was born later. In Family 2, two patients and two carriers were identified, while a fetus was genetically normal. A healthy girl was born later. We concluded that by combining genetic testing and imaging, awareness of the symptoms of PMD and understanding of its molecular biology, there is great benefit for families that are at risk for producing offspring affected with this severe disease.
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PMID:Combined genetic and imaging diagnosis for two large Chinese families affected with Pelizaeus-Merzbacher disease. 2291 87

Pelizaeus-Merzbacher disease (PMD) is a rare, X-linked recessive disorder characterized by dysmyelination in the central nervous system. PMD results from deletion, mutation, or duplication of the proteolipid protein gene (PLP1) located at Xq22, leading to the failure of axon myelination by oligodendrocytes in the central nervous system. PMD may be suspected when there are clinical manifestations such as nystagmus, developmental delays, and spasticity, and genetic analysis can confirm the diagnosis. Further diagnostic manifestations of the disease include a lack of myelination on brain magnetic resonance (MR) imaging and aberrant N-acetyl aspartate (NAA) and choline concentrations that reflect axonal and myelination abnormalities on phroton MR spectroscopy. We report 5 cases of PMD (in 1 girl and 4 boys). PLP1 duplication was detected in 2 patients. Brain MR analyses and MR spectroscopy were performed for all the patients. The brain MR images showed white matter abnormalities typical of PMD, and the MR spectroscopic images showed diverse patterns of NAA, creatinine, and choline concentrations. We propose that MR spectroscopic analysis of metabolic alterations can aid the PMD diagnosis and can contribute to a better understanding of the pathogenesis of the disease.
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PMID:Magnetic resonance imaging and spectroscopic analysis in 5 cases of Pelizaeus-Merzbacher disease: metabolic abnormalities as diagnostic tools. 2313 88

We reported on a male patient with rare leukoencephalopathy and skeletal abnormalities. The condition was first noticed as a developmental delay, nystagmus and ataxia at 1 year of age. At 4 years of age, he was diagnosed as hypomyelination with skeletal abnormalities from clinical features, brain magnetic resonance imaging (MRI) and skeletal X-rays. His brain MRI revealed diffuse hypomyelination. These findings suggested the classical type of Pelizaeus-Merzbacher disease (PMD) caused by proteolipid protein (PLP)-1 gene or Pelizaeus-Merzbacher-like disease (PMLD). However, we found neither mutation nor duplication of PLP-1. The patient had severe growth retardation and general skeletal dysplasia compatible with spondylo-epi-metaphyseal dysplasia; however the mutation of discoidin domain receptor (DDR) 2 gene was absent. The co-morbidity of hypomyelination with skeletal abnormalities is rare. We performed array CGH and no causal copy number variation was recognized. Alternatively, this condition may have been caused by a mutation of the gene encoding a molecule that functions in both cerebral myelination and skeletal development.
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PMID:A case of cerebral hypomyelination with spondylo-epi-metaphyseal dysplasia. 2323 15

Pelizaeus-Merzbacher disease (PMD) is an X-linked recessive disorder affecting myelination of the central nervous system, and is caused by mutations of the proteolipid protein 1 (PLP1) gene. Clinical manifestations of PMD are variable and major features include progressive nystagmus, spasticity, tremor, ataxia, and psychomotor delay. We describe a classical PMD patient who had been misdiagnosed as cerebral palsy. He had nystagmus and psychomotor delay since infancy and tremor with ataxia developing gradually. Brain MRI revealed demyelination over white matter of the cerebral hemispheres and posterior limbs of the internal capsules. Positive family history led to subsequent mutation analysis, which identified a novel mutation (c.88G>C) in PLP1 in the proband, as well as his affected brother and maternal uncle, and asymptomatic maternal grandmother, mother and two sisters. Therefore, PMD should be considered in a cerebral palsy-like patient with or without positive family history. Mutation analysis is crucial for early diagnosis and further genetic counseling.
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PMID:Pelizaeus-Merzbacher disease, easily misdiagnosed as cerebral palsy: a report of a three-generation family. 2359 42

Proteolipid protein 1 (PLP1) gene-related disorders due to mutations in the PLP1 include a wide spectrum of X-linked disorders ranging from severe connatal Pelizaeus-Merzbacher disease (PMD) to spastic paraplegia 2 (SPG2). Duplications, deletions or point mutations in coding and noncoding regions of the PLP1 gene may occur. We report the clinical, neuroradiologic and molecular findings in six patients from two unrelated families. The affected males showed severe mental retardation, spastic tetraparesis, inability of walking and pes cavus at onset in early infancy. Brain magnetic resonance imaging (MRI) showed hypomyelination and brain atrophy. Nystagmus was never observed. The affected females showed adult-onset progressive spastic paraparesis leading to wheel-chair dependency and subtle white matter changes on brain MRI. Molecular studies in the two families identified two different intronic mutations, the novel c.622+2T>C and the known c.622+1G>A, leading to the skipping of PLP1-exon 4. The clinical presentation of the affected males did not consistently fit in any of the PLP1-related disorder subtypes (i.e., connatal or classic PMD, SPG2 and 'PLP1 null syndrome'), and in addition, the carrier females were symptomatic despite the severe clinical picture of their respective probands. This study provides new insight into the genotype-phenotype correlations of patients with PLP1 splice-site mutations.
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PMID:Further genotype-phenotype correlation emerging from two families with PLP1 exon 4 skipping. 2371 21

Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) is a rare leukoencephalopathy first described by van der Knaap in 2002. Diffuse cerebral hypomyelination and atrophy of the basal ganglia and cerebellum characterize H-ABC. We report a 9-year-old Japanese boy with H-ABC who had been suspected to have Pelizaeus Merzbacher disease. Brain MRI revealed delayed myelination, however, no other remarkable abnormal laboratory findings were found. PLP1 gene mutation was not detected and he had no nystagmus. He was diagnosed as having H-ABC at the age of 8 years because of supratentorial hypomyelination and progressive atrophy of the basal ganglia and cerebellum on the follow-up MRI. This boy's condition was clinically more severe than those with other reported patients with H-ABC.
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PMID:[A boy with hypomyelination with atrophy of the basal ganglia and cerebellum]. 2385 11


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