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 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Joubert syndrome (JS) is a primarily autosomal recessive condition characterized by hypotonia, ataxia, abnormal eye movements, and intellectual disability with a distinctive mid-hindbrain malformation (the "molar tooth sign"). Variable features include retinal dystrophy, cystic kidney disease, liver fibrosis and polydactyly. Recently, substantial progress has been made in our understanding of the genetic basis of JS, including identification of seven causal genes (NPHP1, AHI1, CEP290, RPGRIP1L, TMEM67/MKS3, ARL13B and CC2D2A). Despite this progress, the known genes account for <50% of cases and few strong genotype-phenotype correlations exist in JS; however, genetic testing can be prioritized based on clinical features. While all seven JS genes have been implicated in the function of the primary cilium/basal body organelle (PC/BB), little is known about how the PC/BB is required for brain, kidney, retina and liver development/function, nor how disruption of PC/BB function leads to diseases of these organs. Recent work on the function of the PC/BB indicates that the organelle is required for multiple signaling pathways including sonic hedgehog, WNT and platelet derived growth factor. Due to shared clinical features and underlying molecular pathophysiology, JS is included in the rapidly expanding group of disorders called ciliopathies. The ciliopathies are emerging as models for more complex diseases, where sequence variants in multiple genes contribute to the phenotype expressed in any given patient.
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PMID:Joubert syndrome: insights into brain development, cilium biology, and complex disease. 1977 11

Joubert syndrome is an autosomal recessive disorder that is characterized by a variable combination of central nervous system, respiratory and eye anomalies. It is a syndrome with a variable phenotype: partial or complete absence of the cerebellar vermis is seen in all patients, while other cardinal findings include episodic tachypnea and apnea in the neonatal period, jerky eye movements, hypotonia, severe mental handicap, developmental delay, ataxia and impaired equilibrium. Even within sibships the phenotype may vary, making it difficult to establish the exact clinical diagnostic boundaries of Joubert syndrome. A case of Joubert syndrome in a newborn is reported and the importance of recognizing the syndrome in the neonatal period so that specific and effective supportive measures can be started as soon as possible is stressed.
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PMID:Joubert syndrome: Report of a neonatal case. 2001 35

Patients with Joubert syndrome 2 (JBTS2) suffer from a neurological disease manifested by psychomotor retardation, hypotonia, ataxia, nystagmus, and oculomotor apraxia and variably associated with dysmorphism, as well as retinal and renal involvement. Brain MRI results show cerebellar vermis hypoplasia and additional anomalies of the fourth ventricle, corpus callosum, and occipital cortex. The disease has previously been mapped to the centromeric region of chromosome 11. Using homozygosity mapping in 13 patients from eight Ashkenazi Jewish families, we identified a homozygous mutation, R12L, in the TMEM216 gene, in all affected individuals. Thirty individuals heterozygous for the mutation were detected among 2766 anonymous Ashkenazi Jews, indicating a carrier rate of 1:92. Given the small size of the TMEM216 gene relative to other JBTS genes, its sequence analysis is warranted in all JBTS patients, especially those who suffer from associated anomalies.
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PMID:Joubert syndrome 2 (JBTS2) in Ashkenazi Jews is associated with a TMEM216 mutation. 2003 50

Joubert syndrome is a rare autosomal recessive disorder, which is characterized by absence or underdevelopment of the cerebellar vermis and severe developmental delay. The other common features include ataxia, an abnormal breathing pattern, abnormal eye movements and hypotonia. We report the anesthetic management in a 13-year-old girl with Joubert syndrome, scheduled for cauterization of nasal mucosa under general anesthesia. She had episodes of tachypnea and apnea. Oral midazolam 10 mg and famotidine 20 mg were administered 30 min before surgery. Anesthesia was induced and maintained with sevoflurane and nitrous oxide in oxygen. Vecuronium 2 mg was used to facilitate tracheal intubation. Mechanical ventilation was performed with a low ventilation setting of respiratory rate 5 beats x min(-1) and peak inspiratory pressure 9 cm H2O to maintain normal end-tidal CO2. Flurbiprofen axetil 30 mg was administered intravenously for analgesia, because opioids are not recommended. After reversal of muscle relaxation by atropin 0.5 mg and neostigmine 1.5 mg, her trachea was extubated. She did not develop postoperative apnea. In this patient with Joubert syndrome, midazolam, sevoflurane, nitrous oxide and flurbiprofen axetil were used without any complications.
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PMID:[General anesthesia for a girl with Joubert syndrome]. 2022 61

Developmental delay and subsequent impaired cognitive functions are present in almost all patients with Joubert syndrome (JS). We report on a 20-year-old woman with mild clinical signs of JS (minimal truncal ataxia and oculomotor apraxia) but typical molar tooth sign on neuroimaging, normal full scale (IQ=93), verbal (IQ=93), and performance intelligence quotient (IQ=94). Only minor difficulties in visual-spatial organization and in some executive functions could be detected. This pattern of deficits is partly reminiscent of the cerebellar cognitive affective syndrome. Her diagnosis was only reached following the diagnosis of JS in two brothers with severe cognitive impairment. Molecular investigations demonstrated a homozygous mutation in the INPP5E gene. This exceptional observation confirms that normal cognitive functions are possible in JS and corroborates the well known intrafamilial variability.
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PMID:Normal cognitive functions in joubert syndrome. 2044 24

Joubert syndrome (JS) and related disorders (JSRD) are a group of developmental delay/multiple congenital anomalies syndromes in which the obligatory hallmark is the molar tooth sign (MTS), a complex midbrain-hindbrain malformation visible on brain imaging, first recognized in JS. Estimates of the incidence of JSRD range between 1/80,000 and 1/100,000 live births, although these figures may represent an underestimate. The neurological features of JSRD include hypotonia, ataxia, developmental delay, intellectual disability, abnormal eye movements, and neonatal breathing dysregulation. These may be associated with multiorgan involvement, mainly retinal dystrophy, nephronophthisis, hepatic fibrosis and polydactyly, with both inter- and intra-familial variability. JSRD are classified in six phenotypic subgroups: Pure JS; JS with ocular defect; JS with renal defect; JS with oculorenal defects; JS with hepatic defect; JS with orofaciodigital defects. With the exception of rare X-linked recessive cases, JSRD follow autosomal recessive inheritance and are genetically heterogeneous. Ten causative genes have been identified to date, all encoding for proteins of the primary cilium or the centrosome, making JSRD part of an expanding group of diseases called "ciliopathies". Mutational analysis of causative genes is available in few laboratories worldwide on a diagnostic or research basis. Differential diagnosis must consider in particular the other ciliopathies (such as nephronophthisis and Senior-Loken syndrome), distinct cerebellar and brainstem congenital defects and disorders with cerebro-oculo-renal manifestations. Recurrence risk is 25% in most families, although X-linked inheritance should also be considered. The identification of the molecular defect in couples at risk allows early prenatal genetic testing, whereas fetal brain neuroimaging may remain uninformative until the end of the second trimester of pregnancy. Detection of the MTS should be followed by a diagnostic protocol to assess multiorgan involvement. Optimal management requires a multidisciplinary approach, with particular attention to respiratory and feeding problems in neonates and infants. Cognitive and behavioral assessments are also recommended to provide young patients with adequate neuropsychological support and rehabilitation. After the first months of life, global prognosis varies considerably among JSRD subgroups, depending on the extent and severity of organ involvement.
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PMID:Joubert Syndrome and related disorders. 2061 30

Joubert syndrome is a disorder characterized by ataxia, developmental delay, oculomotor anomalies, and breathing irregularities, with cerebellar vermian and midbrain dysgenesis. The molar tooth sign, reflecting the midbrain dysgenesis of Joubert syndrome, is the neuroradiological hallmark and is an essential sign in the identification of this condition. Variable vermian agenesis, an expanded fourth ventricle, and a large posterior cranial fossa with a normal brainstem are typical of Dandy-Walker malformation. The authors report a case in which a Dandy-Walker malformation coexisted with Joubert syndrome, but initially prevented the ''molar tooth sign'' from being recognized because of an important cystic dilatation of the fourth ventricle. In this article, they discuss the importance of the re-examination of brain magnetic resonance features after decompression of the posterior cranial fossa in a patient with Dandy-Walker malformation and additional clinical neurological or systemic abnormalities typical of Joubert syndrome, to not miss the correct diagnosis.
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PMID:Dandy-Walker malformation masking the molar tooth sign: an illustrative case with magnetic resonance imaging follow-up. 2082 32

Joubert syndrome is a rare genetic disorder of childhood that is characterized by hypoplasia or agenesis of the cerebellar vermis in addition to brainstem malformations. Ataxia, hypotonia, developmental delay, and apnea-hyperpnea are the most prominent clinical symptoms of Joubert syndrome, but this condition can also affect multiple organs, making the clinical phenomenology of Joubert syndrome quite diverse. Seizures are the most common neurological complications of Joubert syndrome, but its neurological sequelae are poorly described because Joubert syndrome is very rare. Here we report an acute ischemic stroke in a 21-year-old woman with Joubert syndrome who had no conventional risk factors for early onset cerebrovascular disease. To date, this is the first report of an ischemic stroke in a patient with Joubert syndrome, and we believe this case may suggest an association between Joubert syndrome and extremely early onset cerebrovascular disease.
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PMID:Joubert syndrome presenting with young-age onset ischemic stroke: a possible etiologic association. 2111 47

Huntingtin-associated protein 1 (HAP1) is an essential component of the stigmoid body (STB) and known as a possible neuroprotective interactor with causative proteins for Huntington's disease, spinal and bulbar muscular atrophy, spinocerebellar ataxia type 17 (SCA17), and Joubert syndrome. To clarify what other causative molecules HAP1/STB could interact with, we cloned normal causative genes for several neural disorders from human brain RNA library and evaluated their subcellular interaction with HAP1/STB by immunocytochemistry and immunoprecipitation after cotransfection into Neuro2a cells. The results clearly showed that HAP1/STB interacts with the normal ataxin-3 through Josephin domain and polyglutamine-expanded mutants derived from SCA3 as well. The findings suggest that HAP1/STB could modify the physiological function of normal ataxin-3 and pathogenesis of SCA3 attributable to the mutant ataxin-3.
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PMID:Interaction of ataxin-3 with huntingtin-associated protein 1 through Josephin domain. 2138 98

A group of disorders with disparate symptomatology, including congenital cerebellar ataxia, retinal blindness, liver fibrosis, polycystic kidney disease, and polydactyly, have recently been united under a single disease mechanism called 'ciliopathies'. The ciliopathies are due to defects of the cellular antenna known as the primary cilium, a microtubule-based extension of cellular membranes found in nearly all cell types. Key among these ciliopathies is Joubert syndrome, displaying ataxia, oculomotor apraxia, and mental retardation* with a pathognomonic 'molar tooth sign' on brain magnetic resonance imaging. The importance of ciliary function in neuronal development has been appreciated only in the last decade with the classification of Joubert syndrome as a ciliopathy. This, together with the identification of many of the clinical features of ciliopathies in individuals with Joubert syndrome and the localization of Joubert syndrome's causative gene products at or near the primary cilium, have defined a new class of neurological disease. Cilia are involved in diverse cellular processes including protein trafficking, photoreception, embryonic axis patterning, and cell cycle regulation. Ciliary dysfunction can affect a single tissue or manifest as multi-organ involvement. Ciliary defects have been described in retinopathies such as retinitis pigmentosa and Leber congenital amaurosis (defects in photoreceptor ciliary protein complexes), renal syndromes with nephronophthisis and cystic dysplastic kidneys, and liver conditions such as fibrosis and biliary cirrhosis. Recognizing the diverse presentations of the ciliopathies and screening strategies following diagnosis is an important part of the treatment plan of children with cilia-related disorders.
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PMID:The ciliopathies in neuronal development: a clinical approach to investigation of Joubert syndrome and Joubert syndrome-related disorders. 2167 65


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