Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There is growing clinical evidence supporting a connection between copper deficiency and subacute combined degeneration. While nearly half of patients with copper deficiency myelopathy exhibit MRI abnormalities, signal changes are often ill-defined in distribution. We report a patient with sensory ataxia and spastic paraplegia from copper deficiency whose MRI demonstrates abnormal signal restricted to the dorsal and lateral columns, providing clear radiological support of an association between hypocupremia and combined system degeneration.
 ...
PMID:Subacute combined degeneration due to copper deficiency. 1880 57

Hereditary movement disorders comprise a group of genetically defined diseases characterized by an impaired control of movements, ataxia and/or spasticity. Affected individuals are disabled, their quality of life significantly reduced and their life expectancy shortened. One or more genetic causes have been identified for many of these diseases, including Huntington's disease, Wilson's disease, spinocerebellar ataxias, recessive ataxias, hereditary spastic paraplegia and hereditary dystonias. Due to their characteristic molecular and biochemical pathogenesis, these rare diseases can often serve as models for more common disorders such as Alzheimer's disease or Parkinson's disease. The primary tasks of the German Network of Hereditary Movement Disorders (GeNeMove), funded by the German Ministry for Education and Research (BMBF), are to co-ordinate basic scientific research and clinical research into rare hereditary movement disorders and to improve the cooperation between the German centers specializing in hereditary movement disorders. For each of the diseases in its scope, GeNeMove works at creating standardized documentation of symptoms and the disease's progressive course over time; developing rating scales for clinical examinations and guidelines for therapy; improving genetic testing; fostering genetic research; and collecting samples of DNA, tissue, CSF and blood from sufferers of the disease for biobanks.
 ...
PMID:[Hereditary movement disorders]. 1805 48

RNA is not a simple intermediate between DNA and proteins. RNA is widely transcribed from a variety of genomic regions, and researchers are extensively exploring the functional roles and the regulations of non-coding RNAs and small RNAs including siRNAs and mRNAs. In addition, the human genome project disclosed that we humans carry as few as approximately 22,000 genes. Humans employ tissue-specific and developmental stage-specific alternative splicing to generate a large variety of proteins in a specific cell at a specific developmental stage. Neurological disorders are not the exceptions that can escape from aberrations of the splicing machinery. A large variety of neurological disorders is causally associated with RNA pathologies, but this lecture was mostly focused on aberrant splicings due to pathological alterations of splicing cis- and trans-elements. The neurological diseases covered include congenital myasthenic syndromes, genetic forms of Parkinson's disease, spastic paraplegia, myotonic dystrophy types 1 and 2, sporadic Alzheimer's disease, facioscapulohumeral dystrophy, fragile X-associated tremor/ ataxia syndrome, Rett syndrome, Prader-Willi syndrome, spinocerebellar atrophy type 8, and Waardenburg-Shah syndrome. Potential therapeutic modalities targeting RNA are addressed on congenital myasthenic syndromes, Duchenne muscular dystrophy, spinal muscular atrophy, and familial dysautonomia.
 ...
PMID:[RNA pathologies in neurological disorders]. 1821 Aug 2

The mitochondrial m-AAA protease has a crucial role in axonal development and maintenance. Human mitochondria possess two m-AAA protease isoenzymes: a hetero-oligomeric complex, composed of paraplegin and AFG3L2 (Afg3 like 2), and a homo-oligomeric AFG3L2 complex. Loss of function of paraplegin (encoded by the SPG7 gene) causes hereditary spastic paraplegia, a disease characterized by retrograde degeneration of cortical motor axons. Spg7(-/-) mice show a late-onset degeneration of long spinal and peripheral axons with accumulation of abnormal mitochondria. In contrast, Afg3l2(Emv66/Emv66) mutant mice, lacking the AFG3L2 protein, are affected by a severe neuromuscular phenotype, due to defects in motor axon development. The role of the homo-oligomeric m-AAA protease and the extent of cooperation and redundancy between the two isoenzymes in adult neurons are still unclear. Here we report an early-onset severe neurological phenotype in Spg7(-/-) Afg3l2(Emv66/+) mice, characterized by loss of balance, tremor and ataxia. Spg7(-/-) Afg3l2(Emv66/+) mice display acceleration and worsening of the axonopathy observed in paraplegin-deficient mice. In addition, they show prominent cerebellar degeneration with loss of Purkinje cells and parallel fibers, and reactive astrogliosis. Mitochondria from affected tissues are prone to lose mt-DNA and have unstable respiratory complexes. At late stages, neurons contain structural abnormal mitochondria defective in COX-SDH reaction. Our data demonstrate genetic interaction between the m-AAA isoenzymes and suggest that different neuronal populations have variable thresholds of susceptibility to reduced levels of the m-AAA protease. Moreover, they implicate impaired mitochondrial proteolysis as a novel pathway in cerebellar degeneration.
 ...
PMID:Genetic interaction between the m-AAA protease isoenzymes reveals novel roles in cerebellar degeneration. 1928 3

We report a case of hereditary spastic paraplegia. This 38-year-old Chinese man has had lower limb weakness and spasticity for 10 years. He has normal cognition, no sensory deficits, ataxia or cataracts. There is a strong family history of spastic paraplegia. His paternal grandmother, great uncle, father, and elder brother all had weakness and spasticity. A genetic analysis showed that our patient was heterozygous for the mutation p.P361L in SPG4. He was diagnosed with spastic paraplegia type 4, autosomal dominant (SPG4, MIM#182601). About 40% of cases of hereditary spastic paraplegia are due to mutations in SPG4 encoding for spastin, while 10% are due to mutations in SPG3A encoding for atlastin. To date, 38 hereditary spastic paraplegia loci and 16 hereditary spastic paraplegia-related genes have been identified. Other features include sphincter disturbance and dorsal column disturbance. Our patient may be the first case of SPG4 confirmed by genetic analysis locally. We hope to raise clinicians' awareness of this disease and its possible molecular diagnosis.
 ...
PMID:Hereditary spastic paraplegias. 1949 79

The motor neuron diseases (MNDs) are a group of related neurodegenerative diseases that cause the relative selective progressive death of motor neurons. Exploring the molecular mechanisms underlying MND phenotypes has been hampered by their multifactorial nature and high incidence of sporadic cases, although genetic factors are considered to play a considerable role at present. However, environmental factors, especial exposure to neurotoxic substances, could induce neurotoxicity with the same phenotypes of specific MNDs. Organophosphate-induced delayed neuropathy (OPIDN) is a neurodegenerative disorder characterized by ataxia and progression to paralysis, with a concomitant distal axonal degeneration and secondary demyelination of central and peripheral axons. The inhibition and subsequent aging of neuropathy target esterase (NTE) by organophosphate has been proposed to be the initiating event in OPIDN. NTE is characterized to be a lysophospholipase/phospholipase B mostly in the nervous system to regulate phospholipid homeostasis. Brain-specific deletion of mouse NTE contributes to the behavioral defects characterized by neuronal loss. Recently, mutations in human NTE have also been shown to cause a hereditary spastic paraplegia called NTE-related motor neuron disorder with the same characteristics of OPIDN, which supported the role of NTE abnormalities in OPIDN, and raised the possibility that NTE pathway disturbances contribute to other MNDs. Together with the identified association of paraoxonase polymorphisms with amyotrophic lateral sclerosis, there is a possibility that neurotoxic substances contribute to MND in genetically vulnerable people by gene-environment interactions.
 ...
PMID:Motor neuron diseases and neurotoxic substances: a possible link? 1949 9

Paraplegin and AFG3L2 are ubiquitous nuclear-encoded mitochondrial proteins that form hetero-oligomeric paraplegin-AFG3L2 and homo-oligomeric AFG3L2 complexes in the inner mitochondrial membrane, named m-AAA proteases. These complexes ensure protein quality control in the inner membrane, jointly with a chaperone-like activity on the respiratory chain complexes. Despite coassembling in the same complex, mutations of either paraplegin or AFG3L2 cause two different neurodegenerative disorders. Indeed, mutations of paraplegin are responsible for a recessive form of hereditary spastic paraplegia, whereas mutations of AFG3L2 have been recently associated to a dominant form of spinocerebellar ataxia (SCA28). In this work, we report that the mouse model haploinsufficient for Afg3l2 recapitulates important pathophysiological features of the human disease, thus representing the first SCA28 model. Furthermore, we propose a pathogenetic mechanism in which respiratory chain dysfunction and increased reactive oxygen species production caused by Afg3l2 haploinsufficiency lead to dark degeneration of Purkinje cells and cerebellar dysfunction.
 ...
PMID:Haploinsufficiency of AFG3L2, the gene responsible for spinocerebellar ataxia type 28, causes mitochondria-mediated Purkinje cell dark degeneration. 1962 15

Additional neurological features have recently been described in seven families transmitting pathogenic mutations in OPA1, the most common cause of autosomal dominant optic atrophy. However, the frequency of these syndromal 'dominant optic atrophy plus' variants and the extent of neurological involvement have not been established. In this large multi-centre study of 104 patients from 45 independent families, including 60 new cases, we show that extra-ocular neurological complications are common in OPA1 disease, and affect up to 20% of all mutational carriers. Bilateral sensorineural deafness beginning in late childhood and early adulthood was a prominent manifestation, followed by a combination of ataxia, myopathy, peripheral neuropathy and progressive external ophthalmoplegia from the third decade of life onwards. We also identified novel clinical presentations with spastic paraparesis mimicking hereditary spastic paraplegia, and a multiple sclerosis-like illness. In contrast to initial reports, multi-system neurological disease was associated with all mutational subtypes, although there was an increased risk with missense mutations [odds ratio = 3.06, 95% confidence interval = 1.44-6.49; P = 0.0027], and mutations located within the guanosine triphosphate-ase region (odds ratio = 2.29, 95% confidence interval = 1.08-4.82; P = 0.0271). Histochemical and molecular characterization of skeletal muscle biopsies revealed the presence of cytochrome c oxidase-deficient fibres and multiple mitochondrial DNA deletions in the majority of patients harbouring OPA1 mutations, even in those with isolated optic nerve involvement. However, the cytochrome c oxidase-deficient load was over four times higher in the dominant optic atrophy + group compared to the pure optic neuropathy group, implicating a causal role for these secondary mitochondrial DNA defects in disease pathophysiology. Individuals with dominant optic atrophy plus phenotypes also had significantly worse visual outcomes, and careful surveillance is therefore mandatory to optimize the detection and management of neurological disability in a group of patients who already have significant visual impairment.
 ...
PMID:Multi-system neurological disease is common in patients with OPA1 mutations. 2514 16

In this review, we consider recent work using zebrafish to validate and study the functional consequences of mutations of human genes implicated in a broad range of degenerative and developmental disorders of the brain and spinal cord. Also we present technical considerations for those wishing to study their own genes of interest by taking advantage of this easily manipulated and clinically relevant model organism. Zebrafish permit mutational analyses of genetic function (gain or loss of function) and the rapid validation of human variants as pathological mutations. In particular, neural degeneration can be characterized at genetic, cellular, functional, and behavioral levels. Zebrafish have been used to knock down or express mutations in zebrafish homologs of human genes and to directly express human genes bearing mutations related to neurodegenerative disorders such as spinal muscular atrophy, ataxia, hereditary spastic paraplegia, amyotrophic lateral sclerosis (ALS), epilepsy, Huntington's disease, Parkinson's disease, fronto-temporal dementia, and Alzheimer's disease. More recently, we have been using zebrafish to validate mutations of synaptic genes discovered by large-scale genomic approaches in developmental disorders such as autism, schizophrenia, and non-syndromic mental retardation. Advances in zebrafish genetics such as multigenic analyses and chemical genetics now offer a unique potential for disease research. Thus, zebrafish hold much promise for advancing the functional genomics of human diseases, the understanding of the genetics and cell biology of degenerative and developmental disorders, and the discovery of therapeutics. This article is part of a Special Issue entitled Zebrafish Models of Neurological Diseases.
 ...
PMID:Zebrafish models for the functional genomics of neurogenetic disorders. 2088 84

We report an early onset spastic ataxia-neuropathy syndrome in two brothers of a consanguineous family characterized clinically by lower extremity spasticity, peripheral neuropathy, ptosis, oculomotor apraxia, dystonia, cerebellar atrophy, and progressive myoclonic epilepsy. Whole-exome sequencing identified a homozygous missense mutation (c.1847G>A; p.Y616C) in AFG3L2, encoding a subunit of an m-AAA protease. m-AAA proteases reside in the mitochondrial inner membrane and are responsible for removal of damaged or misfolded proteins and proteolytic activation of essential mitochondrial proteins. AFG3L2 forms either a homo-oligomeric isoenzyme or a hetero-oligomeric complex with paraplegin, a homologous protein mutated in hereditary spastic paraplegia type 7 (SPG7). Heterozygous loss-of-function mutations in AFG3L2 cause autosomal-dominant spinocerebellar ataxia type 28 (SCA28), a disorder whose phenotype is strikingly different from that of our patients. As defined in yeast complementation assays, the AFG3L2(Y616C) gene product is a hypomorphic variant that exhibited oligomerization defects in yeast as well as in patient fibroblasts. Specifically, the formation of AFG3L2(Y616C) complexes was impaired, both with itself and to a greater extent with paraplegin. This produced an early-onset clinical syndrome that combines the severe phenotypes of SPG7 and SCA28, in additional to other "mitochondrial" features such as oculomotor apraxia, extrapyramidal dysfunction, and myoclonic epilepsy. These findings expand the phenotype associated with AFG3L2 mutations and suggest that AFG3L2-related disease should be considered in the differential diagnosis of spastic ataxias.
 ...
PMID:Whole-exome sequencing identifies homozygous AFG3L2 mutations in a spastic ataxia-neuropathy syndrome linked to mitochondrial m-AAA proteases. 2202 84


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>