Genetic analysis of a four generation Indian family with Usher syndrome: a novel insertion mutation in MYO7A

Kumar, Arun and Babu, Mohan and Kimberling, William J and Venkatesh, Conjeevaram Prabhakaran (2004) Genetic analysis of a four generation Indian family with Usher syndrome: a novel insertion mutation in MYO7A. In: Molecular Vision, 10 . pp. 910-916.

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Abstract

Purpose: Usher syndrome (USH) is a rare autosomal recessive disorder characterized by deafness and retinitis pigmentosa. The purpose of this study was to determine the genetic cause of USH in a four generation Indian family. Methods: Peripheral blood samples were collected from individuals for genomic DNA isolation. To determine the linkage of this family to known USH loci, microsatellite markers were selected from the candidate regions of known loci and used to genotype the family. Exon specific intronic primers for the MYO7A gene were used to amplify DNA samples from one affected individual from the family. PCR products were subsequently sequenced to detect mutation. PCR-SSCP analysis was used to determine if the mutation segregated with the disease in the family and was not present in 50 control individuals. Results: All affected individuals had a classic USH type I (USH1) phenotype which included deafness, vestibular dysfunction and retinitis pigmentosa. Pedigree analysis suggested an autosomal recessive mode of inheritance of USH in the family. Haplotype analysis suggested linkage of this family to the USH1B locus on chromosome 11q. DNA sequence analysis of the entire coding region of the MYO7A gene showed a novel insertion mutation c.2663_2664insA in a homozygous state in all affected individuals, resulting in truncation of MYO7A protein. Conclusions: This is the first study from India which reports a novel MYO7A insertion mutation in a four generation USH family. The mutation is predicted to produce a truncated MYO7A protein. With the novel mutation reported here, the total number of USH causing mutations in the MYO7A gene described to date reaches to 75.

Item Type:	Journal Article
Publication:	Molecular Vision
Publisher:	Molecular Vision
Additional Information:	Copyright for this article belongs to Molecular Vision
Department/Centre:	Division of Biological Sciences > Molecular Reproduction, Development & Genetics
Date Deposited:	25 Nov 2004
Last Modified:	19 Sep 2010 04:17
URI:	http://eprints.iisc.ac.in/id/eprint/2359

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