Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

5p deletion syndrome commonly known as cri du chat is well described in affected neonates with catlike cry and hypotonia. Karyotyping will usually show a deletion of the short arm of one chromosome 5 with variable breakpoints. Only a few cases have been reported prenatally, and the fetal form of the syndrome has not been clearly individualised. We report a new case of 5p deletion syndrome diagnosed prenatally in association with Dandy-Walker syndrome and agenesis of the corpus callosum. Other brain anomalies have been reported previously, but this unusual association suggests the use of a specific probe in the investigation of these malformations.
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PMID:Dandy-Walker syndrome and corpus callosum agenesis in 5p deletion. 1584 98

We present a so far unrecognized X-linked mental retardation syndrome with features overlapping with Joubert syndrome (JBS). Two brothers showed hypotonia, mental retardation, ocular abnormalities with impaired vision and colobomas and a breathing pattern compatible with JBS. Neuroimaging revealed cerebellar vermis hypoplasia and ventriculomegaly. A tentative diagnosis of JBS was made, and autosomal recessive inheritance considered most likely. In a subsequent pregnancy that occurred after artificial donor insemination, ultrasound in the 22nd week revealed a Dandy-Walker malformation and hydrocephaly. At autopsy at 34 weeks of gestation, the male infant showed cerebellar vermis aplasia and abnormalities of the brainstem and cerebral cortex. He was considered to have the same disorder as his two half-brothers. This renders the pedigree highly suggestive of X-linked inheritance. The clinical symptoms of this syndrome resemble JBS. However, the absence of the molar tooth sign and the X-linked inheritance do not support JBS. We propose the name X-linked cerebral-cerebellar-coloboma syndrome to distinguish the two disorders. Differentiation of the two disorders is especially important in genetic counseling, where artificial donor insemination may be considered as a means of reducing the recurrence risk, or when female relatives of the patient are concerned.
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PMID:Cerebral, cerebellar, and colobomatous anomalies in three related males: Sex-linked inheritance in a newly recognized syndrome with features overlapping with Joubert syndrome. 1588 74

We describe two brothers with isolated Dandy-Walker malformation (DWM). Interestingly, brain stem dysgenesis and abnormal gyral pattern were also observed in the sibs. They presented with psychomotor retardation and macrocrania. Both suffered from hypotonia with brisk deep tendon reflexes and ataxic gait. They had bilateral optic atrophy and the visual evoked potentials documented prolonged latencies. Further, motor and sensory conduction velocities were normal. Chromosomal examinations for the sibs and their parents showed normal results. The majority of cases are sporadic but rare reports of recurrence in siblings exist. The parents' consanguinity and the recurrence in a subsequent pregnancy suggest an autosomal recessive inheritance pattern. Our report adds more weight that brain stem dysgenesis could be associated with DWM, increasing the spectrum of heterogeneity of this malformation.
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PMID:Isolated Dandy-Walker malformation associated with brain stem dysgenesis in male sibs. 1656 60

An 8-year-old boy presenting with hypotonia, moderate mental retardation, developmental delay, and psychomotor retardation is reported. Magnetic resonance imaging of the brain at age 3 years revealed a Dandy-Walker variant. Cytogenetic analysis of the peripheral blood revealed a derivative chromosome 12 with unknown additional material attached to the distal region of the long arm of chromosome 12. The parental karyotypes were normal. Spectral karyotyping (SKY) using the 24-color SKY probes and fluorescence in situ hybridization (FISH) using the specific 7p, 7q, 12p, and 12q telomeric probes confirmed a duplication of distal 7p and a deletion of terminal 12q. The karyotype of the proband was designated as 46,XY.ish der(12)t(7;12) (p21.2;q24. 33)(SKY+, 7pTEL+, 12qTEL-). The present case provides evidence for the association of partial trisomy 7p (7p21.2-->pter) and partial monosomy 12q (12q24.33-->qter) with a cerebellar malformation and the usefulness of SKY and FISH in the identification of a de novo aberrant chromosome resulting from an unbalanced translocation.
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PMID:Spectral karyotyping and fluorescence in situ hybridization analysis of de novo partial trisomy 7p (7p21.2-->pter) and partial monosomy 12q (12q24.33-->qter). 1671 78

Meckel syndrome (MKS) is a rare lethal autosomal recessive disorder characterized by the presence of occipital encephalocele, cystic kidneys, fibrotic changes of the liver and polydactyly. Joubert syndrome (JS)-related disorders (JSRDs) or cerebello-oculo-renal syndromes (CORS) are a group of recessively inherited conditions characterized by a molar tooth sign (MTS) on cranial MRI, a set of core clinical features (developmental delay/mental retardation, hypotonia, ataxia, episodic breathing abnormalities, abnormal eye movements) and variable involvement of other systems including renal, ocular, central nervous system, craniofacial, hepatic, and skeletal. A significant clinical overlap between MKS and JSRD/CORS has been recognized in the literature. We describe a group of 10 Hutterite patients, of which 7 had been previously diagnosed with MKS, with a JSRD. Clinical features include variable early mortality, cognitive handicap, a characteristic dysmorphic facial appearance, hypotonia, ataxia, abnormal breathing pattern, nystagmus, and MTS on MRI. Additional features include occipital encephalocele, posterior fossa fluid collections resembling Dandy-Walker malformation, hydrocephalus, coloboma, and renal disease. This JSRD is a recognizable dysmorphic syndrome characterized by hypertelorism, deep-set eyes, down-slanting palpebral fissures, ptosis, arched eyebrows with medial sparseness, square nasal tip, short philtrum with tented upper lip, open mouth with down-turned corners, and posteriorly rotated low-set ears. Renal disease is present in 70% of patients and is characterized by cystic kidneys, abnormalities in renal function and hypertension. Homozygous deletions of NPHP1 and the known loci for JS/JSRD and MKS were excluded by identity-by-descent mapping studies suggesting that this condition in the Hutterites represents yet another locus for a JSRD.
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PMID:Meckel syndrome in the Hutterite population is actually a Joubert-related cerebello-oculo-renal syndrome. 1760 1

Dandy-Walker syndrome (DWS) is a congenital brain malformation involving the cerebellum and fourth ventricle. We report a 6-month-old girl with DWS presenting an initially normal ventricular system and mild cyst-like lesion over the posterior fossa as assessed by postnatal brain sonography. However, symptoms and signs of increased intracranial cerebral pressure in terms of frequent vomiting and tense anterior fontanel developed, and these were associated with mild hypotonia and poor neck support, and upward-gaze palsy at the age of 6 months. Magnetic resonance imaging revealed a huge cystic lesion of the fourth ventricle, which filled the posterior fossa and ventricular dilatation. The tentorium was progressively displaced upward by the cyst. A nearly complete agenesis of the cerebellar vermis was also confirmed. After a successful endoscopic third ventriculostomy, a series of brain magnetic resonance imaging scans, taken during a follow-up survey, showed normal lateral and third ventricles. Consequently, symptoms of intracranial cerebral pressure resolved, and a developmental milestone was achieved. In conclusion, DWS can be confirmed postpartum, and endoscopic third ventriculostomy was found to be a preferential operative procedure for DWS with hydrocephalus. It may be effective for patients younger than 1 year.
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PMID:Successful treatment of Dandy-Walker syndrome by endoscopic third ventriculostomy in a 6-month-old girl with progressive hydrocephalus: a case report and literature review. 2138 57

We report 24 patients with holoprosencephaly (HPE) spectrum screened for Del 7q36 and subtelomere 13q. They were divided according to the type of HPE into: 6 alobar, 15 semilobar, 1 lobar and 2 middle interhemispheric variant (MIH). All patients presented with global developmental delay. Microcephaly was in 83.3% and midfacial developmental defects were in the form of; cyclopia, arrhinia and agnathia in 2 patients (8.3%), premaxillary agenesis in 2 patients (8.3%), cleft lip and palate in 7 patients (29.2%), hypotelorism in 8 patients (33.3%) and hypertelorism in 9 patients (37.5%). The neurological deficits were as follows: abnormal tone and spasticity were present in all of them with exceptional of a single patient with MIH who presented with hypotonia and was able to walk independently at the age of 3 years, athetoid and/or dystonic movements of limbs in 22 patients, seizures in twelve patients (50%) and abnormal EEG in 15 patients (62.5%). Poor temperature regulation was found in 50% of patients and diabetes insipidus was documented in 3 patients (12.5%). The MRI showed complete or partial fusion of basal ganglia and thalami in 21 patients (87.5%) and 19 patients (79.2%) respectively, fused mesencephalon in 8 patients (33.3%), incomplete separation of mesencephalon from diencephalon in 4 patients (16.7%), dorsal cyst in 10 patients (41.7%), abnormal gyral pattern anteriorly in 15 patients (62.5%), anterior located sylvian fissures in 22 patients (99.7%), complete or partial agenesis of the corpus callosum (ACC) in all patients and Dandy-Walker malformation (DWM) in three patients (12.5%). A small occipital cephalocele was detected clinically and radiological as atretic type in MIH patient. Karyotype analysis demonstrated 47, XY+13 in a patient with alobar holoprosencephaly, 46, XY,t(12;13) (q13q24.1;q14q33) in a semilobar case associated with DWM, 46, XY, del(13)(q34) in one semilobar case and three cases had del 7q36 using FISH technique in two semilobar cases and one lobar case. Conclusion: This study highlights the clinical spectrum in patients with HPE and report a case of HPE and DWM associated with t(12;13). Neuroimaging delineated the pathogenesis underlying developmental defects in HPE. Accurate molecular diagnosis is crucial for further understanding of the pathogenesis of HPE.
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PMID:Holoprosencephaly spectrum among Egyptian patients: clinical and cytogenetic study. 2580 14

Joubert syndrome (JS) is a recessive neurodevelopmental disorder characterized by hypotonia, ataxia, abnormal eye movements, and variable cognitive impairment. It is defined by a distinctive brain malformation known as the "molar tooth sign" on axial MRI. Subsets of affected individuals have malformations such as coloboma, polydactyly, and encephalocele, as well as progressive retinal dystrophy, fibrocystic kidney disease, and liver fibrosis. More than 35 genes have been associated with JS, but in a subset of families the genetic cause remains unknown. All of the gene products localize in and around the primary cilium, making JS a canonical ciliopathy. Ciliopathies are unified by their overlapping clinical features and underlying mechanisms involving ciliary dysfunction. In this work, we identify biallelic rare, predicted-deleterious ARMC9 variants (stop-gain, missense, splice-site, and single-exon deletion) in 11 individuals with JS from 8 families, accounting for approximately 1% of the disorder. The associated phenotypes range from isolated neurological involvement to JS with retinal dystrophy, additional brain abnormalities (e.g., heterotopia, Dandy-Walker malformation), pituitary insufficiency, and/or synpolydactyly. We show that ARMC9 localizes to the basal body of the cilium and is upregulated during ciliogenesis. Typical ciliopathy phenotypes (curved body shape, retinal dystrophy, coloboma, and decreased cilia) in a CRISPR/Cas9-engineered zebrafish mutant model provide additional support for ARMC9 as a ciliopathy-associated gene. Identifying ARMC9 mutations as a cause of JS takes us one step closer to a full genetic understanding of this important disorder and enables future functional work to define the central biological mechanisms underlying JS and other ciliopathies.
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PMID:Mutations in ARMC9, which Encodes a Basal Body Protein, Cause Joubert Syndrome in Humans and Ciliopathy Phenotypes in Zebrafish. 2862 4

The association between KCTD3 gene and neurogenetic disorders has only been published recently. In this report, we describe the clinical phenotype associated with 2 pathogenic variants in KCTD3 gene. Seven individuals (including one set of monozygotic twin) from 4 consanguineous families presented with developmental epileptic encephalopathy, global developmental delay, central hypotonia, progressive peripheral hypertonia, and variable dysmorphic facial features. Posterior fossa abnormalities (ranging from Dandy-Walker malformation to isolated hypoplasia of the cerebellar vermis) were consistently observed in addition to other variable neuroradiological abnormalities such as hydrocephalus and abnormal brain myelination. One patient also had a multicystic kidney. Whole exome sequencing revealed 2 probably pathogenic homozygous variants in KCTD3 gene that fully segregated with the disease. KCTD3 gene belongs to a family of accessory subunits that regulate the biophysical properties of ion channels, and is highly expressed in the kidney and brain. In this largest series to date on KCTD3-mutated patients, we show that biallelic loss of function mutations in KCTD3 lead to a consistent phenotype of developmental epileptic encephalopathy and abnormal cerebellum on brain imaging.
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PMID:Phenotypic characterization of KCTD3-related developmental epileptic encephalopathy. 2940 73

Joubert syndrome is a rare autosomal recessive disorder characterized by hyperpnoea and eye movements, hypotonia, ataxia, developmental retardation with neuropathologic abnormalities of cerebellum and brainstem including inherited hypoplasia or aplasia of vermis. Cerebellar vermin anomalies are described in other disorders such as Dandy-Walker and rhombencephalon synapsis. These disorders should be distinguished from Joubert syndrome on the basis of imaging. Comparison with typical imaging and clinical findings may be helpful for appropriate diagnosis.
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PMID:Joubert syndrome: A classic case. 3091 30


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