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

A 25-year-old man was referred to our hospital because of repetitive cessation of breathing during sleep. He had a history of longstanding ataxia, motor delay, and mental retardation and had been diagnosed with cerebral palsy. Neurological examination revealed ataxia, general hypotonia and wide-based, shuffling gait. Magnetic resonance imaging showed vermian aplasia and dilated fourth ventricle, consistent with Joubert syndrome. Polysomnography revealed repetitive tachypnea followed by central apnea. Tachypneic episodes were elicited by brief arousals. Nasal continuous positive airway pressure eliminated neither tachypnea nor apnea. This case indicates that a patient with Joubert syndrome may survive into adulthood and present as a case of sleep-disordered breathing.
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PMID:[Joubert syndrome diagnosed based on sleep-disordered breathing in a 25-year-old man--case report]. 1830 70

Joubert syndrome (JS) and related disorders are a group of autosomal-recessive conditions sharing the "molar tooth sign" on axial brain MRI, together with cerebellar vermis hypoplasia, ataxia, and psychomotor delay. JS is suggested to be a disorder of cilia function and is part of a spectrum of disorders involving retinal, renal, digital, oral, hepatic, and cerebral organs. We identified mutations in ARL13B in two families with the classical form of JS. ARL13B belongs to the Ras GTPase family, and in other species is required for ciliogenesis, body axis formation, and renal function. The encoded Arl13b protein was expressed in developing murine cerebellum and localized to the cilia in primary neurons. Overexpression of human wild-type but not patient mutant ARL13B rescued the Arl13b scorpion zebrafish mutant. Thus, ARL13B has an evolutionarily conserved role mediating cilia function in multiple organs.
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PMID:Mutations in the cilia gene ARL13B lead to the classical form of Joubert syndrome. 1867 51

Joubert syndrome (JS) is a developmental brain disorder characterized by cerebellar vermis hypoplasia, abnormal eye movement, ataxia and mental retardation. Mutations in CEP290 mutations are responsible for the cerebello-oculo-renal subtype of JS that includes kidney cysts and retinal degeneration, two phenotypes commonly linked to ciliopathies. CEP290 mutations are also associated with Meckel-Gruber syndrome and Bardet-Biedl syndrome (BBS). Here we demonstrate that CEP290 interacts with a centriolar satellite protein PCM-1, which is implicated in BBS4 function. CEP290 binds to PCM-1 and localizes to centriolar satellites in a PCM-1- and microtubule-dependent manner. The depletion of CEP290 disrupts subcellular distribution and protein complex formation of PCM-1. In accord with PCM-1's role in microtubule organization, CEP290 knockdown causes the disorganization of the cytoplasmic microtubule network. Moreover, we show that both CEP290 and PCM-1 are required for ciliogenesis and are involved in the ciliary targeting of Rab8, a small GTPase shown to collaborate with BBS protein complex to promote ciliogenesis. Our results suggest that PCM-1 is a potential mediator that may link CEP290 with BBS proteins in common molecular pathways.
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PMID:CEP290 interacts with the centriolar satellite component PCM-1 and is required for Rab8 localization to the primary cilium. 1877 92

Joubert syndrome (JBTS) is an autosomal recessive disorder characterized by cerebellum and brainstem malformations. Individuals with JBTS have abnormal breathing and eye movements, ataxia, hypotonia, and cognitive difficulty, and they display mirror movements. Mutations in the Abelson-helper integration site-1 gene (AHI1) cause JBTS in humans, suggesting that AHI1 is required for hindbrain development; however AHI1 may also be required for neuronal function. Support for this idea comes from studies demonstrating that the AHI1 locus is associated with schizophrenia. To gain further insight into the function of AHI1 in both the developing and mature central nervous system, we determined the spatial and temporal expression patterns of the gene products of AHI1 orthologs throughout development, in human, mouse, and zebrafish. Murine Ahi1 was distributed throughout the cytoplasm, dendrites, and axons of neurons, but was absent in glial cells. Ahi1 expression in the mouse brain was observed as early as embryonic day 10.5 and persisted into adulthood, with peak expression during the first postnatal week. Murine Ahi1 was observed in neurons of the hindbrain, midbrain, and ventral forebrain. Generally, the AHI1/Ahi1/ahi1 orthologs had a conserved distribution pattern in human, mouse, and zebrafish, but mouse Ahi1 was not present in the developing and mature cerebellum. Ahi1 was also observed consistently in the stigmoid body, a poorly characterized cytoplasmic organelle found in neurons. Overall, these results suggest roles for AHI1 in neurodevelopmental processes that underlie most of the neuroanatomical defects in JBTS, and perhaps in neuronal functions that contribute to schizophrenia.
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PMID:Species differences in the expression of Ahi1, a protein implicated in the neurodevelopmental disorder Joubert syndrome, with preferential accumulation to stigmoid bodies. 1878 27

Joubert syndrome and related disorders (JSRD) are primarily autosomal-recessive conditions characterized by hypotonia, ataxia, abnormal eye movements, and intellectual disability with a distinctive mid-hindbrain malformation. Variable features include retinal dystrophy, cystic kidney disease, and liver fibrosis. JSRD are included in the rapidly expanding group of disorders called ciliopathies, because all six gene products implicated in JSRD (NPHP1, AHI1, CEP290, RPGRIP1L, TMEM67, and ARL13B) function in the primary cilium/basal body organelle. By using homozygosity mapping in consanguineous families, we identify loss-of-function mutations in CC2D2A in JSRD patients with and without retinal, kidney, and liver disease. CC2D2A is expressed in all fetal and adult tissues tested. In ciliated cells, we observe localization of recombinant CC2D2A at the basal body and colocalization with CEP290, whose cognate gene is mutated in multiple hereditary ciliopathies. In addition, the proteins can physically interact in vitro, as shown by yeast two-hybrid and GST pull-down experiments. A nonsense mutation in the zebrafish CC2D2A ortholog (sentinel) results in pronephric cysts, a hallmark of ciliary dysfunction analogous to human cystic kidney disease. Knockdown of cep290 function in sentinel fish results in a synergistic pronephric cyst phenotype, revealing a genetic interaction between CC2D2A and CEP290 and implicating CC2D2A in cilium/basal body function. These observations extend the genetic spectrum of JSRD and provide a model system for studying extragenic modifiers in JSRD and other ciliopathies.
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PMID:CC2D2A is mutated in Joubert syndrome and interacts with the ciliopathy-associated basal body protein CEP290. 1895 Jul 40

Over the last decade, increasing evidence of cognitive functions of the cerebellum during development and learning processes could be ascertained. Posterior fossa malformations such as cerebellar hypoplasia or Joubert syndrome are known to be related to developmental problems in a marked to moderate extent. More detailed analyses reveal special deficits in attention, processing speed, visuospatial functions, and language. A study about Dandy Walker syndrome states a relationship of abnormalities in vermis lobulation with developmental problems. Further lobulation or volume abnormalities of the cerebellum and/or vermis can be detected in disorders as fragile X syndrome, Downs's syndrome, William's syndrome, and autism. Neuropsychological studies reveal a relation of dyslexia and attention deficit disorder with cerebellar functions. These functional studies are supported by structural abnormalities in neuroimaging in these disorders. Acquired cerebellar or vermis atrophy was found in groups of children with developmental problems such as prenatal alcohol exposure or extreme prematurity. Also, focal lesions during childhood or adolescence such as cerebellar tumor or stroke are related with neuropsychological abnormalities, which are most pronounced in visuospatial, language, and memory functions. In addition, cerebellar atrophy was shown to be a bad prognostic factor considering cognitive outcome in children after brain trauma and leukemia. In ataxia teleangiectasia, a neurodegenerative disorder affecting primarily the cerebellar cortex, a reduced verbal intelligence quotient and problems of judgment of duration are a hint of the importance of the cerebellum in cognition. In conclusion, the cerebellum seems to play an important role in many higher cognitive functions, especially in learning. There is a suggestion that the earlier the incorrect influence, the more pronounced the problems.
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PMID:Cerebellar disorders in childhood: cognitive problems. 1905 77

Joubert syndrome is a rare autosomal recessive disease characterized by hypotonia, ataxia, episodic hyperpnea, psychomotor retardation, abnormal ocular movements, cerebellar vermian hypoplasia, and molar tooth sign on magnetic resonance imaging. Neuroleptic malignant syndrome is an uncommon and potentially fatal idiosynchratic reaction of antipsychotic drugs, in which the clinical scenario encompass muscular rigidity, hyperthermia, autonomic dysfunction, altered consciousness, high creatinine phosphokinase levels, and leukocytosis. This report describes a case of neuroleptic malignant syndrome due to risperidone in a child with Joubert syndrome.
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PMID:Neuroleptic malignant syndrome due to risperidone treatment in a child with Joubert syndrome. 1933 Dec 62

Joubert syndrome (JS) is an inherited disorder characterized by transient episodic hyperpnea, ataxia, and vermian hypoplasia. Typical imaging findings of JS include hypoplasia or aplasia of the cerebellar vermis, thick and elongated superior cerebellarpeduncles and an abnormally deep interpeduncular fossa with 'molar tooth sign'. We present a case of JS associated with deep cerebral sulci and fissures, polymicrogyria, and additional findings of posterior reversible encephalopathy syndrome associated with renal involvement.
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PMID:Joubert syndrome associated with new MRI findings and posterior reversible encephalopathy syndrome. 1940 75

Abnormalities of deep cerebellar nuclei in Joubert syndrome have been previously reported only in rare autopsy cases. Epilepsy in association with Joubert syndrome is also rarely reported. In two new cases of patients with Joubert syndrome, bilateral hypoplasia of deep cerebellar nuclei was detected in vivo by magnetic resonance imaging. One of the patients had drug-resistant epilepsy. Both patients received clinical examination, electroencephalography, neuropsychologic testing, and high-resolution magnetic resonance imaging (1.5 T). Patient 1, a 7-year-old boy, had muscular hypotonia, periodic tachypnea, mild ataxia, global developmental delay, exotropia, and polydactyly. Patient 2, a 23-year-old woman, had muscular hypotonia, epilepsy with pharmacoresistant generalized tonic-clonic seizures, learning disability, esotropia, and mild gait ataxia. Abnormalities of deep cerebellar nuclei might contribute to the pathophysiology of epilepsy in patients with Joubert syndrome.
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PMID:Hypoplasia of deep cerebellar nuclei in joubert syndrome. 1943 86

Joubert syndrome (JS) is characterized by hypotonia, ataxia, developmental delay, and a typical neuroimaging finding, the so-called "molar tooth sign" (MTS). The association of MTS and polymicrogyria (PMG) has been reported as a distinct JS-related disorder (JSRD). So far, five patients have been reported with this phenotype, only two of them being siblings. We report on one additional family, describing a living child with JS and PMG, and the corresponding neuropathological picture in the aborted brother. No mutations were detected in the AHI1 gene, the only so far associated with the JS + PMG phenotype. Moreover, linkage analysis allowed excluding all known gene loci, suggesting further genetic heterogeneity.
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PMID:Joubert syndrome with bilateral polymicrogyria: clinical and neuropathological findings in two brothers. 1953 93


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