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)

The authors report eight children, who presented in the first year of life with isolated head stereotypies, that corresponded neither to the usual normal 'rhythmic habit patterns of infancy', nor to various types of abnormal repetitive head movements described in young children. Their head stereotypies closely resembled those described in bobble-head doll syndrome. The neurological status evidenced axial hypotonia, ataxia, oculomotor abnormalities, motor and language delay. The patients were followed for several years clinically and with video recordings. No single aetiology was found. Computed tomography (CT) or magnetic resonance imaging (MRI) show a congenital cerebellar abnormality in two children but no hydrocephalus. The outcome of these children showed in all but one patient a normal cognitive and psychosocial development, even though the head stereotypies are still present in six of eight patients and all remain significantly clumsy. The association of head stereotypies and motor delay should prompt a search for cerebellar congenital malformation. The outcome of those patients was much better than originally anticipated and these head stereotypies are not related either to mental retardation, or to psychopathology. The possible mechanisms involved are also discussed.
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PMID:A special type of head stereotypies in children with developmental (?cerebellar) disorder: description of 8 cases and literature review. 1236 1

The Smith-Magenis syndrome is a rare, complex multisystemic disorder featuring, mental retardation and multiple congenital anomalies caused by a heterozygous interstitial deletion of chromosome 17p11.2. The phenotype of Smith-Magenis syndrome is characterized by a distinct pattern of features including infantile hypotonia, generalized complacency and lethargy in infancy, minor skeletal (brachycephaly, brachydactyly) and craniofacial features, ocular abnormalities, middle ear and laryngeal abnormalities including hoarse voice, as well as marked early expressive speech and language delays, psychomotor and growth retardation, and a 24-hour sleep disturbance. A striking neurobehavioral pattern of stereotypies, hyperactivity, polyembolokoilamania, onychotillomania, maladaptive and self-injurious and aggressive behavior is observed with increasing age. The diagnosis of Smith-Magenis syndrome is based upon the clinical recognition of a constellation of physical, developmental, and behavioral features in combination with a sleep disorder characterized by inverted circadian rhythm of melatonin secretion. Many of the features of Smith-Magenis syndrome are subtle in infancy and early childhood, and become more recognizable with advancing age. Infants are described as looking "cherubic" with a Down syndrome-like appearance, whereas with age the facial appearance is that of relative prognathism. Early diagnosis requires awareness of the often subtle clinical and neurobehavioral phenotype of the infant period. Speech delay with or without hearing loss is common. Most children are diagnosed in mid-childhood when the features of the disorder are most recognizable and striking. While improvements in cytogenetic analysis help to bring cases to clinical recognition at an earlier age, this review seeks to increase clinical awareness about Smith-Magenis syndrome by presenting the salient features observed at different ages including descriptions of the neurologic and behavioral features. Detailed review of the circadian rhythm disturbance unique to Smith-Magenis syndrome is presented. Suggestions for management of the behavioral and sleep difficulties are discussed in the context of the authors' personal experience in the setting of an ongoing Smith-Magenis syndrome natural history study.
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PMID:Neurologic and developmental features of the Smith-Magenis syndrome (del 17p11.2). 1664 92

This study examined the nature and frequency of neurological and EEG abnormalities in 60 young children (ages 2-6 years) with pervasive developmental disorders. A number of standard neurological functions could not be adequately assessed due to the young age of the children and/or limited comprehension and cooperation. The most common neurological deficits were hyporeflexia, stereotypies, and hypotonia. EEG abnormalities were identified in 32% of the children while only two children were known to have clinical seizures. The frequency of cases with hypotonia or hyporeflexia was more common than in older children with this diagnosis. Results also indicate that EEG abnormalities are common in this young population but clinical seizures are rare, confirming other studies.
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PMID:Abnormalities on the neurological examination and EEG in young children with pervasive developmental disorders. 1704 91

Mutations in the human X-linked cyclin-dependent kinase-like 5 (CDKL5) gene have been shown to cause infantile spasms as well as Rett syndrome (RTT)-like phenotype. To date, less than 25 different mutations have been reported. So far, there are still little data on the key clinical diagnosis criteria and on the natural history of CDKL5-associated encephalopathy. We screened the entire coding region of CDKL5 for mutations in 183 females with encephalopathy with early seizures by denaturing high liquid performance chromatography and direct sequencing, and we identified in 20 unrelated girls, 18 different mutations including 7 novel mutations. These mutations were identified in eight patients with encephalopathy with RTT-like features, five with infantile spasms and seven with encephalopathy with refractory epilepsy. Early epilepsy with normal interictal EEG and severe hypotonia are the key clinical features in identifying patients likely to have CDKL5 mutations. Our study also indicates that these patients clearly exhibit some RTT features such as deceleration of head growth, stereotypies and hand apraxia and that these RTT features become more evident in older and ambulatory patients. However, some RTT signs are clearly absent such as the so called RTT disease profile (period of nearly normal development followed by regression with loss of acquired fine finger skill in early childhood and characteristic intensive eye communication) and the characteristic evolution of the RTT electroencephalogram. Interestingly, in addition to the overall stereotypical symptomatology (age of onset and evolution of the disease) resulting from CDKL5 mutations, atypical forms of CDKL5-related conditions have also been observed. Our data suggest that phenotypic heterogeneity does not correlate with the nature or the position of the mutations or with the pattern of X-chromosome inactivation, but most probably with the functional transcriptional and/or translational consequences of CDKL5 mutations. In conclusion, our report show that search for mutations in CDKL5 is indicated in girls with early onset of a severe intractable seizure disorder or infantile spasms with severe hypotonia, and in girls with RTT-like phenotype and early onset seizures, though, in our cohort, mutations in CDKL5 account for about 10% of the girls affected by these disorders.
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PMID:Key clinical features to identify girls with CDKL5 mutations. 1879 Aug 21

We report a 2-year-old girl with early onset seizures variant of Rett syndrome with a deletion at Xp22 detected by multiplex ligation-dependent probe amplification (MLPA) technique. This patient presented with tonic seizures at 7 days of life. Subsequently, she developed infantile spasms at three months and finally refractory myoclonic epilepsy. She demonstrated severe encephalopathy with hypotonia, deceleration of head growth, with eye gaze but limited eye pursuit, no language, limited hand use, and intermittent hand stereotypies. This combination of clinical features, suggestive of early onset variant of Rett syndrome led us to screen the CDKL5 gene. In a first step, screening of the whole coding sequence of the CDKL5 gene revealed no point mutations. In a second step, we searched gross rearrangements by MLPA and identified a microdeletion affecting both the promoter and exon 1 in CDKL5. Subsequent analysis on a Nimblegen HD2 microarray confirmed a deletion of approximately 300 kb at Xp22, including the BEND2, SCML2, and CDKL5 genes. In conclusion, our report suggests that searching for large rearrangements in CDKL5 should be considered in girls with early onset seizures and Rett-like features.
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PMID:Epileptic encephalopathy in a girl with an interstitial deletion of Xp22 comprising promoter and exon 1 of the CDKL5 gene. 1945 95

The 9q Subtelomeric Deletion Syndrome (9qSTDS) is clinically characterized by mental retardation, childhood hypotonia, and facial dysmorphisms. Haploinsufficiency of the EHMT1 gene has been demonstrated to be responsible for its core phenotype. In a significant number of patients behavioral abnormalities like aggression, impulsivity, and chaotic behaviors are present as well as epileptic phenomena. Reports about the developmental, behavioral, and neuropsychiatric aspects of 9qSTDS are scarce and mostly limited to young patients only. In this report, the behavioral and neuropsychiatric characteristics of one male and one female middle-aged patient are described in whom the genetic diagnosis, interstitial and telomeric 9q deletion, respectively, was established recently. In both patients a remarkable sleep disturbance, characterized by frequent awakenings and daytime sleepiness, was present as well as a prominent apathy syndrome. The observed motor signs such as rigid flexure of the arms and finger stereotypies persisted over a period of many years and could therefore not be viewed as symptoms of catatonia. It is concluded that the proposed behavioral phenotype of 9qSTDS comprises at least an erratic sleep pattern and an enduring severe apathy.
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PMID:Behavioral phenotype in the 9q subtelomeric deletion syndrome: a report about two adult patients. 1964 12

The Forkhead box G1 (FOXG1) is a transcription factor that is critical for forebrain development, where it promotes progenitor proliferation and suppresses premature neurogenesis. Recently, the FOXG1 gene was implicated in the molecular aetiology of the congenital variant of Rett syndrome. So far, 15 FOXG1 molecular alterations, including only eight point mutations, have been reported. We screened the FOXG1 gene in a cohort of 206 MECP2 and CDKL5 mutation negative patients (136 females and 70 males) with severe encephalopathy and microcephaly. The screening was negative in all males, but two de novo mutations (c.1248C>G, p.Y416X and c.460_461dupG, p.E154GfsX300) were identified in two unrelated girls. Both patients showed neurological symptoms from the neonatal period with poor reactivity, hypotonia, and severe microcephaly. During the first year of life, both patients had feeding difficulties and made slow developmental progress. At 5 years old, the girls were significantly neurologically impaired with gross hypotonia, no language, convergent strabismus, and no voluntary hand use. Moreover, they presented a combination of jerky movements, hand-mouthing, and hand-washing stereotypies. Hence, FOXG1 mutation patients demonstrate severe encephalopathy compatible with the congenital variant, as well as additional features such as absent eye contact, inconsolable crying during the perinatal period, and delayed myelination with thin to hypoplastic corpus callosum. Although the overall frequency of mutations in FOXG1 in females with severe mental retardation and microcephaly appears to be low (1.5%), our findings suggest the requirement to investigate both point mutations and gene dosage in the FOXG1 gene in patients with severe encephalopathy with microcephaly and some Rett-like features.
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PMID:Revisiting the phenotype associated with FOXG1 mutations: two novel cases of congenital Rett variant. 1980 73

Inborn errors of metabolism (IEM) are a group of genetic disorders characterized by dysfunction of an enzyme or other protein involved in cellular metabolism.(1) Most IEMs involve the nervous system (neuro-metabolic diseases or NMD). NMD often present with a complex clinical picture: psychomotor retardation and/or regression, pyramidal signs, ataxia, hypotonia and epilepsy and movement disorders.(1) Movement disorders are more frequently part of this complex picture than a predominant symptom, however in some instances the clinical picture may be summarized in an invalidating movement disorder.(2) On a phenomenology basis, one can distinguish eight main types of movement disorders: dystonia and athetosis, chorea, tremor with or without parkinsonism, ballismus, myoclonus, tics and stereotypies. Most of these abnormal involuntary movements generate from a dysfunction or a lesion in the basal ganglia, excepting myoclonus, the origin of which can vary (cortical, brainstem, basal ganglia, spinal and even peripheral nervous system).(3) Classically the most frequently observed movement disorders in NMD are: dystonia, myoclonus, chorea, tremor and parkinsonism (Fig. 1). The primary goal of this article is, departing from the literature and a large personal series, to describe the types of movement disorders most frequently observed in NMD and to discuss their clinical value in the setting of specific types of NMD.
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PMID:Movement disorders in neuro-metabolic diseases. 2001 70

Genome-wide high-resolution array analysis is rapidly becoming a reliable method of diagnostic investigation in individuals with mental retardation and congenital anomalies, leading to the identification of several novel microdeletion and microduplication syndromes. We have identified seven individuals with duplication on chromosome 14q11.2q13.1, who exhibited idiopathic developmental delay and cognitive impairment, severe speech delay, and developmental epilepsy. Among these cases, the minimal common duplicated region on chromosome 14q11.2q13.1 includes only three genes, FOXG1, C14orf23, and PRKD1. We propose that increased dosage of Forkhead Box G1 (FOXG1) is the best candidate to explain the abnormal neurodevelopmental phenotypes observed in our patients. Deletions and inactivating mutations of FOXG1 have been associated with a Rett-like syndrome characterized by hypotonia, irritability, developmental delay, hand stereotypies, and deceleration of head growth. FOXG1, encoding a brain-specific transcription factor, has an important role in the developing brain. In fact, in vivo studies in chicken brain demonstrated that overexpression of FOXG1 results in thickening of the neuroepithelium and outgrowth of the telencephalon and mesencephalum, secondary to a reduction in neuroepithelial cell apoptosis.
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PMID:Duplications of FOXG1 in 14q12 are associated with developmental epilepsy, mental retardation, and severe speech impairment. 2225 24

Narcolepsy with cataplexy is characterized by daytime sleepiness, cataplexy (sudden loss of bilateral muscle tone triggered by emotions), sleep paralysis, hypnagogic hallucinations and disturbed nocturnal sleep. Narcolepsy with cataplexy is most often associated with human leucocyte antigen-DQB1*0602 and is caused by the loss of hypocretin-producing neurons in the hypothalamus of likely autoimmune aetiology. Noting that children with narcolepsy often display complex abnormal motor behaviours close to disease onset that do not meet the classical definition of cataplexy, we systematically analysed motor features in 39 children with narcolepsy with cataplexy in comparison with 25 age- and sex-matched healthy controls. We found that patients with narcolepsy with cataplexy displayed a complex array of 'negative' (hypotonia) and 'active' (ranging from perioral movements to dyskinetic-dystonic movements or stereotypies) motor disturbances. 'Active' and 'negative' motor scores correlated positively with the presence of hypotonic features at neurological examination and negatively with disease duration, whereas 'negative' motor scores also correlated negatively with age at disease onset. These observations suggest that paediatric narcolepsy with cataplexy often co-occurs with a complex movement disorder at disease onset, a phenomenon that may vanish later in the course of the disease. Further studies are warranted to assess clinical course and whether the associated movement disorder is also caused by hypocretin deficiency or by additional neurochemical abnormalities.
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PMID:Complex movement disorders at disease onset in childhood narcolepsy with cataplexy. 2193 Jun 61


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