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)

Cephalic neural crest cells contribute to the formation of the external and middle ears, the supporting cells of the statoacoustic ganglion, other cranial nerve components, and the face. The anlage of otic sensory structures receive inductive stimuli from adjacent rhombencephalic tissue. The complex series of interactions that guide organogenesis of the outer, middle, and inner ear structures may explain why neurologic dysfunction is likely to be associated with malformations of the ear. We reviewed the records of 100 patients with complex ear anomalies with or without hearing loss. Mean age was 4.2 years (range 1 day-27 years). Malformations, either bilateral (70) or unilateral (30), involved the external ear (94), middle ear (16), and/or inner ear (12). Eighty-five patients had neurologic dysfunction. Cranial nerve dysfunction was found in 56 patients and involved nerves VIII (39 auditory and/or vestibular), VII (22), II (11), VI (8), V (4), III (3), X (3), XII (1), and IX (1). Sixty-four patients had evidence of central nervous system dysfunction such as mental deficiency/developmental delay (44), non-paretic gait disorders (17), hypotonia (16), microcephaly (13), seizures (8), motor deficits (8), autistic features (7), and radiographically confirmed intracranial abnormalities (5). Eleven of 19 children with hypoactive vestibules had delayed motor development or poor balance. Seventy-four patients had anomalies in other organ systems: 56 craniofacial, 28 osseous, 19 cardiac, 16 genito-urinary, 14 ocular, 11 gastrointestinal, and 7 cutaneous. Sixty-one patients had syndromic conditions, 32 of them branchial arch syndromes. The level of cognitive competence was not related to severity of craniofacial, ear, or cranial nerve abnormality. Children with ear malformations deserve neurologic and pediatric evaluations in addition to an otologic work-up.
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PMID:Neurologic findings in children with ear malformations. 362 8

Light and electronmicroscopic findings in two cases. Neuropediatrics 12: 215-31 (1981). Two cases of infantile spinal muscular atrophy (Werdnig-Hoffmann disease) are described in unrelated children deceased at 11 months (acute clinical onset at 6 months) and 2 years (onset at birth). Severe respiratory difficulties, hypotonia, muscular weakness and depressed tendon reflexes were the main clinical features. Bulbar palsy, bilateral ptosis, pale optic discs and atactic movements of the hands were observed in the child deceased at 11 months. Besides severe loss of anterior horn cells and neurogenic muscle atrophy there was evidence of an extensive sensory involvement in both cases. Shrinkage, vacuolation as well as chromatolytic changes of dorsal root ganglion cells, together with the evidence of a primary axonal damage in sural nerve biopsies were interpreted in terms of ganglioneuropathy of the primary sensory neurons. An invasion of fibrous astrocytes into dorsal roots constituted another striking anomaly in one case as well as a pronounced degeneration of cranial nerves V and VIII in the other case, a finding not hitherto reported in Werdnig-Hoffmann disease.
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PMID:Sensory ganglioneuropathy in infantile spinal muscular atrophy. Light and electronmicroscopic findings in two cases. 729 Mar 43

This paper reports three females and two males with a distinctive congenital syndrome characterized by severe congenital hypotonia, facial diplegia, jaw ankylosis, velo-pharyngeal incoordination, pyramidal tract signs, and ocular motor apraxia. Patients were followed up at ages ranging from 20 months to 16 years. All cases of this syndrome are sporadic, without dysmorphological features, chromosomal, or MRI brain abnormalities. Electrophysiological studies indicate the brainstem as the site of the neurological dysfunction. Post-mortem CNS study of one of the patients demonstrated neuronal depletion of the IV, VII, VIII, and IX cranial nerve nuclei and intact morphology of the cerebral hemispheres. A vascular accident, early in foetal life, is the most likely cause of the clinical picture. The extent of brainstem involvement and its related clinical findings distinguishes these patients from those with Moebius, Pierre Robin, or Cogan syndromes. Outcome is better than what could be anticipated during the first few months of life given the severity of symptoms. Intelligence or developmental quotients are within the normal range for their age. Facial hypomimia, feeding, and speech articulatory performance difficulties are the main disabilities observed in these patients at follow-up.
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PMID:Brainstem dysgenesis: report of five patients with congenital hypotonia, multiple cranial nerve involvement, and ocular motor apraxia. 1282 4

We describe two patients (a Filipino boy aged 2.7 years and a Kuwaiti girl aged 4.8 Years) with clinical and MRI findings consistent with the diagnosis of pontine tegmental cap dysplasia (PTCD) and compare them with 23 other cases reported in the literature. Both presented with feeding problems (VII nerve), sensori-neural deafness (VIII nerve) and hypotonia from birth and later developed corneal opacities due to loss of corneal sensation (V nerve). They have severe psychomotor developmental delay. The MRI of their brain showed a flattened ventral pons, vaulted "cap"- like structure protruding into 4th ventricle and a "molar tooth" sign. One of our patients also had Tetralogy of Fallot (TOF) successfully corrected. The other had no extracranial manifestations. The findings in our patients are similar to those reported except for the occurrence of TOF which has not been reported before in association with PTCD.
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PMID:Pontine tegmental cap dysplasia: report of two new cases from Kuwait. 2522 Jul 82

The cerebellum is involved in sensorimotor operations, cognitive tasks and affective processes. Here, we revisit the concept of the cerebellar syndrome in the light of recent advances in our understanding of cerebellar operations. The key symptoms and signs of cerebellar dysfunction, often grouped under the generic term of ataxia, are discussed. Vertigo, dizziness, and imbalance are associated with lesions of the vestibulo-cerebellar, vestibulo-spinal, or cerebellar ocular motor systems. The cerebellum plays a major role in the online to long-term control of eye movements (control of calibration, reduction of eye instability, maintenance of ocular alignment). Ocular instability, nystagmus, saccadic intrusions, impaired smooth pursuit, impaired vestibulo-ocular reflex (VOR), and ocular misalignment are at the core of oculomotor cerebellar deficits. As a motor speech disorder, ataxic dysarthria is highly suggestive of cerebellar pathology. Regarding motor control of limbs, hypotonia, a- or dysdiadochokinesia, dysmetria, grasping deficits and various tremor phenomenologies are observed in cerebellar disorders to varying degrees. There is clear evidence that the cerebellum participates in force perception and proprioceptive sense during active movements. Gait is staggering with a wide base, and tandem gait is very often impaired in cerebellar disorders. In terms of cognitive and affective operations, impairments are found in executive functions, visual-spatial processing, linguistic function, and affective regulation (Schmahmann's syndrome). Nonmotor linguistic deficits including disruption of articulatory and graphomotor planning, language dynamics, verbal fluency, phonological, and semantic word retrieval, expressive and receptive syntax, and various aspects of reading and writing may be impaired after cerebellar damage. The cerebellum is organized into (a) a primary sensorimotor region in the anterior lobe and adjacent part of lobule VI, (b) a second sensorimotor region in lobule VIII, and (c) cognitive and limbic regions located in the posterior lobe (lobule VI, lobule VIIA which includes crus I and crus II, and lobule VIIB). The limbic cerebellum is mainly represented in the posterior vermis. The cortico-ponto-cerebellar and cerebello-thalamo-cortical loops establish close functional connections between the cerebellum and the supratentorial motor, paralimbic and association cortices, and cerebellar symptoms are associated with a disruption of these loops.
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PMID:Consensus Paper: Revisiting the Symptoms and Signs of Cerebellar Syndrome. 2610 56

More than a century after the description of its cardinal components, the cerebellar motor syndrome (CMS) remains a cornerstone of daily clinical ataxiology, in both children and adults. Anatomically, motor cerebellum involves lobules I-V, VI, and VIII. CMS is typically associated with errors in the metrics of voluntary movements and a lack of coordination. Symptoms and motor signs consist of speech deficits, impairments of limb movements, and abnormalities of posture/gait. Ataxic dysarthria has a typical scanning (explosive with staccato) feature, voice has a nasal character, and speech is slurred. Cerebellar mutism is most common in children and occurs after resection of a large midline cerebellar tumor. Ataxia of limbs includes at various degrees dysmetria (hypermetria: overshoot, hypometria: undershoot), dysdiadochokinesia, cerebellar tremor (action tremor, postural tremor, kinetic tremor, some forms of orthostatic tremor), isometrataxia, disorders of muscle tone (both hypotonia and cerebellar fits), and impaired check and rebound. Handwriting is irregular and some patients exhibit megalographia. Cerebellar patients show an increased body sway with a broad-based stance (ataxia of stance). Gait is irregular and staggering. Delayed learning of complex motor skills may be a prominent feature in children. CMS is currently explained by the inability of the cerebellum to handle feedback signals during slow movements and to create, store, select, and update internal models during fast movements. The cerebellum is embedded in large-scale brain networks and is essential to perform accurate motor predictions related to body dynamics and environmental stimuli. Overall, the observations in children and adults exhibiting a CMS fit with the hypothesis that the cerebellum contains neural representations reproducing the dynamic properties of body, and generates and calibrates sensorimotor predictions. Therapies aiming at a reinforcement or restoration of internal models should be implemented to cancel CMS in cerebellar ataxias. The developmental trajectory of the cerebellum, the immature motor behavior in children, and the networks implicated in CMS need to be taken into account.
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PMID:Cerebellar motor syndrome from children to the elderly. 2990 37

Spinocerebellar ataxia type 29 (SCA29) is autosomal dominant congenital ataxia characterized by early-onset motor delay, hypotonia, and gait ataxia. Recently, heterozygous missense mutations in an intracellular Ca2+ channel, inositol 1,4,5-trisphosphate (IP3) receptor type 1 (IP3R1), were identified as a cause of SCA29. However, the functional impacts of these mutations remain largely unknown. Here, we determined the molecular mechanisms by which pathological mutations affect IP3R1 activity and Ca2+ dynamics. Ca2+ imaging using IP3R-null HeLa cells generated by genome editing revealed that all SCA29 mutations identified within or near the IP3-binding domain of IP3R1 completely abolished channel activity. Among these mutations, R241K, T267M, T267R, R269G, R269W, S277I, K279E, A280D, and E497K impaired IP3 binding to IP3R1, whereas the T579I and N587D mutations disrupted channel activity without affecting IP3 binding, suggesting that T579I and N587D compromise channel gating mechanisms. Carbonic anhydrase-related protein VIII (CA8) is an IP3R1-regulating protein abundantly expressed in cerebellar Purkinje cells and is a causative gene of congenital ataxia. The SCA29 mutation V1538M within the CA8-binding site of IP3R1 completely eliminated its interaction with CA8 and CA8-mediated IP3R1 inhibition. Furthermore, pathological mutations in CA8 decreased CA8-mediated suppression of IP3R1 by reducing protein stability and the interaction with IP3R1. These results demonstrated the mechanisms by which pathological mutations cause IP3R1 dysfunction, i.e., the disruption of IP3 binding, IP3-mediated gating, and regulation via the IP3R-modulatory protein. The resulting aberrant Ca2+ homeostasis may contribute to the pathogenesis of cerebellar ataxia.
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PMID:Aberrant IP3 receptor activities revealed by comprehensive analysis of pathological mutations causing spinocerebellar ataxia 29. 3042 31

Neonatal encephalopathy manifests with altered sensorium, tone abnormalities, and often with abnormal movements and seizures. The causes are heterogeneous and many. We report a late preterm neonate who presented with depressed sensorium, cranial nerve abnormalities, mixed hypertonia and hypotonia, and respiratory failure. Neuroimaging and electrophysiological studies were normal. She had neutropenia and elevated lactates in blood. Her dried blood spot analysis by tandem MS/MS showed normal acylcarnitine and amino acid profile. Plasma and cerebro spinal fluid (CSF) amino acid quantification were inconclusive, CSF folate was normal. Urine organic acid analysis showed elevated lactate. Semi-quantitative analysis of urine showed borderline elevation of 3-methylglutaconic acid. Diagnosis of 3-methylglutaconic aciduria (3MGA) type VIII was suggested by whole-exome sequencing, which revealed a homozygous, likely pathogenic, missense mutation in Exon 2 of HTRA2 gene (chr2.74757898A>C). Her parents were found to be carriers of the same mutation. This underscores the importance of genetic studies in the evaluation of neonatal neuro-metabolic disorders. We report the first case of 3MGA type VIII from our region with a review of already reported 11 cases.
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PMID:3-Methylglutaconic aciduria type VIII in an Indian neonate. 3244 93