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)

MTM1, MTMR2, and SBF2 belong to a family of proteins called the myotubularins. X-linked myotubular myopathy, a severe congenital disorder characterized by hypotonia and generalized muscle weakness in newborn males, is caused by mutations in MTM1 (Laporte et al., 1996). Charcot-Marie-Tooth types 4B1 and 4B2 are severe demyelinating neuropathies caused by mutations in MTMR2 (Bolino et al., 2000) and SBF2/MTMR13 (Senderek et al., 2003), respectively. Although several myotubularins are known to regulate phosphoinositide-phosphate levels in cells, little is known about the actual cellular process that is defective in patients with these diseases. Mutations in worm MTM-6 and MTM-9, myotubularins belonging to two subgroups, disorganize phosphoinositide 3-phosphate localization and block endocytosis in the coelomocytes of Caenorhabditis elegans. We demonstrate that MTM-6 and MTM-9 function as part of a complex to regulate an endocytic pathway that involves the Arf6 GTPase, and we define protein domains required for MTM-6 activity.
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PMID:Disease-related myotubularins function in endocytic traffic in Caenorhabditis elegans. 1456 69

Congenital hypomyelinating neuropathy is a rare condition characterized by prenatal, neonatal or early infantile onset of hypotonia, paresis and areflexia. Most of the few patients described in literature die within the first years of life. Histopathologically there are no or thin myelin sheaths. Mutations have been described in the following genes, MPZ, EGR2, PMP22, and MTMR2. Here we describe a family with a heterozygous mutation in MPZ, confirmed in two generations.
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PMID:Congenital hypomyelinating neuropathy, a long term follow-up study in an affected family. 1782 53

Early onset hereditary motor and sensory neuropathies are rare disorders encompassing congenital hypomyelinating neuropathy with disease onset in the direct post-natal period and Dejerine-Sottas neuropathy starting in infancy. The clinical spectrum, however, reaches beyond the boundaries of these two historically defined disease entities. De novo dominant mutations in PMP22, MPZ and EGR2 are known to be a typical cause of very early onset hereditary neuropathies. In addition, mutations in several other dominant and recessive genes for Charcot-Marie-Tooth disease may lead to similar phenotypes. To estimate mutation frequencies and to gain detailed insights into the genetic and phenotypic heterogeneity of early onset hereditary neuropathies, we selected a heterogeneous cohort of 77 unrelated patients who presented with symptoms of peripheral neuropathy within the first year of life. The majority of these patients were isolated in their family. We performed systematic mutation screening by means of direct sequencing of the coding regions of 11 genes: MFN2, PMP22, MPZ, EGR2, GDAP1, NEFL, FGD4, MTMR2, PRX, SBF2 and SH3TC2. In addition, screening for the Charcot-Marie-Tooth type 1A duplication on chromosome 17p11.2-12 was performed. In 35 patients (45%), mutations were identified. Mutations in MPZ, PMP22 and EGR2 were found most frequently in patients presenting with early hypotonia and breathing difficulties. The recessive genes FGD4, PRX, MTMR2, SBF2, SH3TC2 and GDAP1 were mutated in patients presenting with early foot deformities and variable delay in motor milestones after an uneventful neonatal period. Several patients displaying congenital foot deformities but an otherwise normal early development carried the Charcot-Marie-Tooth type 1A duplication. This study clearly illustrates the genetic heterogeneity underlying hereditary neuropathies with infantile onset.
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PMID:Genetic spectrum of hereditary neuropathies with onset in the first year of life. 2184 Aug 89

Charcot-Marie-Tooth disease (CMT) is a clinically and genetically heterogeneous group of distal symmetric polyneuropathies due to progressive and length-dependent degeneration of peripheral nerves. Cranial nerve involvement has been described in association with various CMT-genes mutations, such as GDAP1, TRPV4, MFN2, MTMR2 and EGR2. Compound heterozygous mutations in the TRIM2 gene, encoding an E3 ubiquitin ligase, were previously identified in two patients with early-onset axonal CMT (CMT2). One of them also had bilateral vocal cord paralysis. The aim of this study is to further delineate the phenotypic and molecular genetic features of TRIM2-related CMT. We studied clinical, genetic and neurophysiological aspects of two unrelated CMT2 patients. Genetic analysis was performed by next generation sequencing of a multigene CMT panel. Patients presented with congenital hypotonia and bilateral clubfoot, delayed motor milestones, and severely progressive axonal neuropathy. Interestingly, along with vocal cord paralysis, they exhibited clinical features secondary to the involvement of several other cranial nerves, such as facial weakness, dysphagia, dyspnoea and acoustic impairment. Genetic analysis revealed two novel TRIM2 mutations in each patient. Our results expand the genotypic and phenotypic spectrum of TRIM2 deficiency showing that cranial nerves involvement is a core feature in this CMT2-subtype. Its finding should prompt physicians to suspect TRIM2 neuropathy. Conversely, patients carrying TRIM2 variants should be carefully evaluated for the presence of cranial nerve dysfunction in order to prevent and manage its impact on auditory and respiratory function and nutrition.
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PMID:Expanding the phenotypic spectrum of TRIM2-associated Charcot-Marie-Tooth disease. 3281 44