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)

Trisomy 5p and Miller-Dieker syndromes frequently are the result of unbalanced segregations of reciprocal translocations of chromosomes 5 and 17 with other autosomes. The critical regions for the expression of the mentioned syndromes have been mapped to 5p13-->pter, and 17p13.3-->pter. In this report, we describe an 8-year-old girl with mental retardation, postnatal growth deficiency, generalized muscular hypotonia, seizures, microcephaly, cortical atrophy, partial agenesis of corpus callosum, cerebral ventriculomegaly, facial anomalies, patent ductus arteriosus, pectus excavatum, long fingers, and bilateral talipes equinovarus caused by the presence of a 46,XX,der(17)t(5;17)(p13.1;p13.3)mat chromosome complement. Cytogenetic studies of the family confirmed a balanced reciprocal translocation (5;17)(p13.1;p13.3) in her mother, maternal grandfather, maternal aunt, and a female first cousin. Fluorescence in situ hybridization studies on the mother and the proposita using three probes, which map to distal 17p, confirmed the reciprocal translocation in the mother and a terminal deletion in the patient, which resulted in the retention of LIS1 and D17S379 loci and deletion of the 17p telomere. These findings and the phenotype of the proposita, strongly suggest that genes telomeric to LIS1 and locus D17S379 are involved in many clinical findings, including the minor facial anomalies of the Miller-Dieker syndrome.
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PMID:Miller-Dieker syndrome and trisomy 5p in a child carrying a derivative chromosome with a microdeletion in 17p13.3 telomeric to the LIS1 and the D17S379 loci. 1040 60

Neuronal migration disorders of the cerebral cortex form a heterogeneous group of abnormalities, characterised by mental retardation, epilepsy and hypotonia. They are prevalent in 1% of the population and in 20-40% of the untreatable forms of epilepsy. Disorders at the start of the migration result in nodular heterotopias. Bilateral periventricular nodular heterotopias are X-linked disorders, in which cortical neurons are unable to leave their position at the ventricular surface due to the absence of filamin 1. The large group of lissencephalies can be divided into a number of syndromes, each of which is characterised by a gene mutation (LIS1, DCX, RELN). These mutations result in agyria and pachygyria, which are characteristic for this group. A number of these abnormalities, especially the smaller nodular heterotopias and focal cortical dysplasia, may be treated by neurosurgical excision.
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PMID:[Development and developmental disorders of the human brain. III. Neuronal migration disorders of the cerebrum]. 1126 8

Malformations of the cerebral cortex are an important cause of developmental disabilities and epilepsy. Here we review those malformations for which a genetic basis has been elucidated or is suspected and the types of associated epilepsy. Schizencephaly (cleft brain) has a wide anatomo-clinical spectrum, including partial epilepsy in most patients. Familial occurrence is rare. Heterozygous mutations in the EMX2 gene were reported in 13 patients. X-linked bilateral periventricular nodular heterotopia (BPNH) consists of typical BPNH with epilepsy in females and prenatal lethality in males. About 88% of patients have partial epilepsy. Filamin A mutations, all leading to a truncated protein, have been reported in three families and in sporadic patients. The most frequent forms of lissencephaly (agyria-pachygyria) are caused by mutations of LIS1. XLIS mutations cause classical lissencephaly in hemizygous males and subcortical band heterotopia (SBH) in heterozygous females. The thickness of the heterotopic band and the degree of pachygyria correlate with the likelihood of developing Lennox-Gastaut syndrome. Mutations of the coding region of XLIS were found in all reported pedigrees and in 38-91% of sporadic female patients with SBH. With few exceptions, children with LIS1 mutations have isolated lissencephaly, with severe developmental delay and infantile spasms. Autosomal recessive lissencephaly with cerebellar hypoplasia, accompanied by severe developmental delay, seizures, and hypotonia has been associated with mutations of the reelin gene. Fukuyama congenital muscular dystrophy is due to mutations of the fukutin gene and is accompanied by polymicrogyria. Febrile seizures and epilepsy with generalized tonic-convulsions appear in about 50% of children but are usually not severe. Tuberous sclerosis (TS) is caused by mutations in at least two genes, TSC1 and TSC2; 75% of cases are sporadic; 60% of patients have epilepsy, manifested in 50% of them as infantile spasms. TSC1 mutations seem to cause a milder disease with fewer cortical tubers and lower frequency of seizures. Among several syndromes featuring polymicrogyria, bilateral perisylvian polymicrogyria had familial occurrence on several occasions. Genetic heterogeneity is likely, including autosomal recessive, X-linked dominant, X-linked recessive inheritance, and association with 22q11.2 deletions. About 65% of patients have severe epilepsy, often Lennox-Gastaut syndrome.
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PMID:Epilepsy and genetic malformations of the cerebral cortex. 1157 36

We reviewed the epileptogenic cortical malformations for which a causative gene has been cloned or a linkage obtained. X-linked bilateral periventricular nodular heterotopia (BPNH) consists of typical BPNH with epilepsy in female patients and prenatal lethality in most males. About 90% of patients have focal epilepsy. Filamin A mutations have been reported in all families and in approximately 20% of sporadic patients. A rare recessive form of BPNH also has been reported. Most cases of lissencephaly-pachygyria are caused by mutations of LIS1 and XLIS genes. LIS1 mutations cause a more severe malformation posteriorly. Most children have isolated lissencephaly, with severe developmental delay and infantile spasms, but milder phenotypes have been recorded. XLIS usually causes anteriorly predominant lissencephaly in male patients and subcortical band heterotopia (SBH) in female patients. Thickness of the band and severity of pachygyria correlate with the likelihood of developing Lennox-Gastaut syndrome. Mutations of the coding region of XLIS are found in all reported pedigrees and in 50% of sporadic female patients with SBH. Autosomal recessive lissencephaly with cerebellar hypoplasia; accompanied by severe delay, hypotonia, and seizures, has been associated with mutations of the RELN gene. Schizencephaly has a wide anatomoclinical spectrum, including focal epilepsy in most patients. Familial occurrence is rare. Initial reports of heterozygous mutations in the EMX2 gene need confirmation. Among several syndromes featuring polymicrogyria, bilateral perisylvian polymicrogyria shows genetic heterogeneity, including linkage to Xq28 in some pedigrees, autosomal recessive inheritance in others, and association with 22q11.2 deletion in some patients. About 65% of patients have severe epilepsy, often Lennox-Gastaut syndrome. Recessive bilateral frontal polymicrogyria has been linked to chromosome 16q12.2-21.
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PMID:Genetic malformations of the cerebral cortex and epilepsy. 1581 77

Several malformation syndromes with abnormal cortical development have been recognized. Specific causative gene defects and characteristic electroclinical patterns have been identified for some. X-linked periventricular nodular heterotopia is mainly seen in female patients and is often associated with focal epilepsy. FLN1 mutations have been reported in all familial cases and in about 25% of sporadic patients. A rare recessive form of periventricular nodular heterotopia owing to ARGEF2 gene mutations has also been reported in children with microcephaly, severe delay, and early-onset seizures. Lissencephaly-pachygyria and subcortical band heterotopia represent a malformative spectrum resulting from mutations of either the LIS1 or the DCX (XLIS) gene. LIS1 mutations cause a more severe malformation posteriorly. Most children have severe developmental delay and infantile spasms, but milder phenotypes are on record, including posterior subcortical band heterotopia owing to mosaic mutations of LIS1. DCX mutations usually cause anteriorly predominant lissencephaly in male patients and subcortical band heterotopia in female patients. Mutations of the coding region of DCX were found in all reported pedigrees and in about 50% of sporadic female patients with subcortical band heterotopia. Mutations of XLIS have also been found in male patients with anterior subcortical band heterotopia and in female patients with normal brain magnetic resonance imaging. The thickness of the band and the severity of pachygyria correlate with the likelihood of developing severe epilepsy. Autosomal recessive lissencephaly with cerebellar hypoplasia, accompanied by severe delay, hypotonia, and seizures, has been associated with mutations of the reelin (RELN) gene. X-linked lissencephaly with corpus callosum agenesis and ambiguous genitalia in genotypic males is associated with mutations of the ARX gene. Affected boys have severe delay and infantile spasms with suppression-burst electroencephalograms. Early death is frequent. Carrier female patients can have isolated corpus callosum agenesis. Schizencephaly has a wide anatomoclinical spectrum, including focal epilepsy in most patients. Familial occurrence is rare. Initial reports of heterozygous mutations in the EMX2 gene have not been confirmed. Among several syndromes featuring polymicrogyria, bilateral perisylvian polymicrogyria shows genetic heterogeneity, including linkage to chromosome Xq28 in some pedigrees, autosomal dominant or recessive inheritance in others, and an association with chromosome 22q11.2 deletion in some patients. About 65% of patients have severe epilepsy. Recessive bilateral frontoparietal polymicrogyria has been associated with mutations of the GPR56 gene.
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PMID:Neuronal migration disorders, genetics, and epileptogenesis. 1592 Dec 28

The malformations of the cerebral cortex represent a major cause of developmental disabilities, severe epilepsy and reproductive disadvantage. The advent of high-resolution MRI techniques has facilitated the in vivo identification of a large group of cortical malformation phenotypes. Several malformation syndromes caused by abnormal cortical development have been recognised and specific causative gene defects have been identified. Periventricular nodular heterotopia (PNH) is a malformation of neuronal migration in which a subset of neurons fails to migrate into the developing cerebral cortex. X-linked PNH is mainly seen in females and is often associated with focal epilepsy. FLNA mutations have been reported in all familial cases and in about 25% of sporadic patients. A rare recessive form of PNH due ARGEF2 gene mutations has also been reported in children with microcephaly, severe delay and early seizures. Lissencephaly-pachygyria and subcortical band heterotopia (SBH) are disorders of neuronal migration and represent a malformative spectrum resulting from mutations of either LIS1 or DCX genes. LIS1 mutations cause a more severe malformation in the posterior brain regions. Most children have severe developmental delay and infantile spasms, but milder phenotypes are on record, including posterior SBH owing to mosaic mutations of LIS1. DCX mutations usually cause anteriorly predominant lissencephaly in males and SBH in female patients. Mutations of DCX have also been found in male patients with anterior SBH and in female relatives with normal brain magnetic resonance imaging. Autosomal recessive lissencephaly with cerebellar hypoplasia, accompanied by severe delay, hypotonia, and seizures, has been associated with mutations of the reelin (RELN) gene. X-linked lissencephaly with corpus callosum agenesis and ambiguous genitalia in genotypic males is associated with mutations of the ARX gene. Affected boys have severe delay and seizures with suppression-burst EEG. Early death is frequent. Carrier female patients can have isolated corpus callosum agenesis. Among several syndromes featuring polymicrogyria, bilateral perisylvian polymicrogyria shows genetic heterogeneity, including linkage to chromosome Xq28 in some pedigrees, autosomal dominant or recessive inheritance in others, and an association with chromosome 22q11.2 deletion in some patients. About 65% of patients have severe epilepsy. Recessive bilateral frontoparietal polymicrogyria has been associated with mutations of the GPR56 gene. Epilepsy is often present in patients with cortical malformations and tends to be severe, although its incidence and type vary in different malformations. It is estimated that up to 40% of children with drug-resistant epilepsy have a cortical malformation. However, the physiopathological mechanisms relating cortical malformations to epilepsy remain elusive.
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PMID:Genetic malformations of cortical development. 1672 81

The term lissencephaly covers a group of rare malformations sharing the common feature of anomalies in the appearance of brain convolutions (characterised by simplification or absence of folding) associated with abnormal organisation of the cortical layers as a result of neuronal migration defects during embryogenesis. Children with lissencephaly have feeding and swallowing problems, muscle tone anomalies (early hypotonia and subsequently limb hypertonia), seizures (in particular, infantile spasms) and severe psychomotor retardation. Multiple forms of lissencephaly have been described and their current classification is based on the associated malformations and underlying aetiology. Two large groups can be distinguished: classical lissencephaly (and its variants) and cobblestone lissencephaly. In classical lissencephaly (or type I), the cortex appears thickened, with four more or less disorganised layers rather than six normal layers. In the variants of classical lissencephaly, extra-cortical anomalies are also present (total or subtotal agenesis of the corpus callosum and/or cerebellar hypoplasia). The classical lissencephalies and the variant forms can be further divided into several subgroups. Four forms can be distinguished on the basis of their genetic aetiology: anomalies in the LIS1 gene (isolated lissencephaly and Miller-Dieker syndrome), anomalies in the TUBA3 and DCX genes, and lissencephalies caused by mutations in the ARX gene (XLAG syndrome, X-linked lissencephaly with agenesis of the corpus callosum). The incidence of all forms of type I lissencephaly is around 1 in 100,000 births. In addition to these four entities, isolated lissencephalies without a known genetic defect, lissencephalies with severe microcephaly (microlissencephaly) and lissencephalies associated with polymalformative syndromes are also included in the group of classical lissencephalies. Cobblestone lissencephaly (formally referred to as type II) is present in three entities: the Walker-Warburg, Fukuyama and MEB (Muscle-Eye-Brain) syndromes. It is characterised by global disorganisation of cerebral organogenesis with an uneven cortical surface (with a pebbled or cobblestone appearance). Microscopic examination reveals total disorganisation of the cortex and the absence of any distinguishable layers. Management is symptomatic only (swallowing problems require adapted feeding to prevent food aspiration, articular and respiratory physiotherapy to prevent orthopaedic problems resulting from hyptonia and treatment of gastrooesophageal reflux). The epilepsy is often resistant to treatment. The encephalopathy associated with lissencephaly is often very severe and affected children are completely dependent on the carer.
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PMID:[Genetic and clinical aspects of lissencephaly]. 1757 Oct 22

A 10-year-old boy presented with a severe and diffuse mosaic skin hypopigmentation running (in narrow bands) along the lines of Blaschko associated with mosaic areas of alopecia, facial dysmorphism with midface hypoplasia, bilateral punctate cataract, microretrognathia, short neck, pectus excavatum, joint hypermobility, mild muscular hypotonia, generalized seizures, and mild mental retardation. Cranial magnetic resonance imaging revealed hypoplastic corpus callosum (primarily posterior), subcortical band heterotopia, and diffuse subcortical, periventricular cystic-like lesions. Similar dysmorphic features were observed in the child's mother, but with no imaging abnormalities. The facial phenotype coupled with the cysts in the brain was strongly reminiscent of the oculocerebrorenal Lowe syndrome. Full chromosome studies in the parents and the proband and mutation analysis on peripheral blood lymphocytes (and on skin cultured fibroblasts from affected and unaffected skin areas in the child) in the genes for subcortical band heterotopia (DCX (Xq22.3-q23)], lissencephaly (PAFAH1B1, alias LIS1, at 17p13.3), and oculocerebrorenal syndrome of Lowe (OCRL at Xq23-q24)] were unrevealing. This constellation of multiple congenital anomalies including skin hypopigmentation and eye, musculoskeletal, and nervous system abnormalities was sufficiently characterized to be regarded as a novel example of pigmentary mosaicism of the Ito type (i.e., hypomelanosis of Ito).
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PMID:Pigmentary mosaicism, subcortical band heterotopia, and brain cystic lesions. 1938 77