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Mutations in ARHGEF6, encoding a guanine nucleotide exchange factor for Rho GTPases, in patients with X-linked mental retardation 总被引:18,自引:0,他引:18
Kutsche K Yntema H Brandt A Jantke I Nothwang HG Orth U Boavida MG David D Chelly J Fryns JP Moraine C Ropers HH Hamel BC van Bokhoven H Gal A 《Nature genetics》2000,26(2):247-250
X-linked forms of mental retardation (XLMR) include a variety of different disorders and may account for up to 25% of all inherited cases of mental retardation. So far, seven X-chromosomal genes mutated in nonspecific mental retardation (MRX) have been identified: FMR2, GDI1, RPS6KA3, IL1RAPL, TM4SF2, OPHN1 and PAK3 (refs 2-9). The products of the latter two have been implicated in regulation of neural plasticity by controlling the activity of small GTPases of the Rho family. Here we report the identification of a new MRX gene, ARHGEF6 (also known as alphaPIX or Cool-2), encoding a protein with homology to guanine nucleotide exchange factors for Rho GTPases (Rho GEF). Molecular analysis of a reciprocal X/21 translocation in a male with mental retardation showed that this gene in Xq26 was disrupted by the rearrangement. Mutation screening of 119 patients with nonspecific mental retardation revealed a mutation in the first intron of ARHGEF6 (IVS1-11T-->C) in all affected males in a large Dutch family. The mutation resulted in preferential skipping of exon 2, predicting a protein lacking 28 amino acids. ARHGEF6 is the eighth MRX gene identified so far and the third such gene to encode a protein that interacts with Rho GTPases. 相似文献
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Mutation of CDH23, encoding a new member of the cadherin gene family, causes Usher syndrome type 1D 总被引:20,自引:0,他引:20
Bolz H von Brederlow B Ramírez A Bryda EC Kutsche K Nothwang HG Seeliger M del C-Salcedó Cabrera M Vila MC Molina OP Gal A Kubisch C 《Nature genetics》2001,27(1):108-112
Usher syndrome type I (USH1) is an autosomal recessive disorder characterized by congenital sensorineural hearing loss, vestibular dysfunction and visual impairment due to early onset retinitis pigmentosa (RP). So far, six loci (USH1A-USH1F) have been mapped, but only two USH1 genes have been identified: MYO7A for USH1B and the gene encoding harmonin for USH1C. We identified a Cuban pedigree linked to the locus for Usher syndrome type 1D (MIM 601067) within the q2 region of chromosome 10). Affected individuals present with congenital deafness and a highly variable degree of retinal degeneration. Using a positional candidate approach, we identified a new member of the cadherin gene superfamily, CDH23. It encodes a protein of 3,354 amino acids with a single transmembrane domain and 27 cadherin repeats. In the Cuban family, we detected two different mutations: a severe course of the retinal disease was observed in individuals homozygous for what is probably a truncating splice-site mutation (c.4488G-->C), whereas mild RP is present in individuals carrying the homozygous missense mutation R1746Q. A variable expression of the retinal phenotype was seen in patients with a combination of both mutations. In addition, we identified two mutations, Delta M1281 and IVS51+5G-->A, in a German USH1 patient. Our data show that different mutations in CDH23 result in USH1D with a variable retinal phenotype. In an accompanying paper, it is shown that mutations in the mouse ortholog cause disorganization of inner ear stereocilia and deafness in the waltzer mouse. 相似文献
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The problem of fault-tolerant controller design for a class of polytopic uncertain systems with actuator faults is studied in this paper. The actuator faults are presented as a more general and practical continuous fault model. Based on the affine quadratic stability (AQS), the stability of the polytopic uncertain system is replaced by the stability at all corners of the polytope. For a wide range of problems including H∞ and mixed H 2 /H∞ controller design, sufficient conditions are derived to guarantee the robust stability and performance of the closed-loop system in both normal and fault cases. In the framework of the linear matrix inequality (LMI) method, an iterative algorithm is developed to reduce conservativeness of the design procedure. The effectiveness of the proposed design is shown through a flight control example. 相似文献
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Yuxing Mao Ching Y.Suen Wei He .State Key Laboratory of Power Transmission Equipment & System Security New Technology Chongqing University Chongqing P.R.China .Centre for Pattern Recognition Machine Intelligence Concordia University Montreal QC HG M Canada 《系统工程与电子技术(英文版)》2011,(6):1003-1009
A new approach to extraction of affine invariant features of contour image and matching strategy is proposed for shape recognition.Firstly,the centroid distance and azimuth angle of each boundary point are computed.Then,with a prior-defined angle interval,all the points in the neighbor region of the sample point are considered to calculate the average distance for eliminating noise.After that,the centroid distance ratios(CDRs) of any two opposite contour points to the barycenter are achieved as the representation of the shape,which will be invariant to affine transformation.Since the angles of contour points will change non-linearly among affine related images,the CDRs should be resampled and combined sequentially to build one-by-one matching pairs of the corresponding points.The core issue is how to determine the angle positions for sampling,which can be regarded as an optimization problem of path planning.An ant colony optimization(ACO)-based path planning model with some constraints is presented to address this problem.Finally,the Euclidean distance is adopted to evaluate the similarity of shape features in different images.The experimental results demonstrate the efficiency of the proposed method in shape recognition with translation,scaling,rotation and distortion. 相似文献
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