Publications (6)17.93 Total impact
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Article: Association of pathogenic mutations in TULP1 with retinitis pigmentosa in consanguineous Pakistani families.
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ABSTRACT: To identify pathogenic mutations responsible for autosomal recessive retinitis pigmentosa in 5 consanguineous Pakistani families. Affected individuals in the families underwent a detailed ophthalmological examination that consisted of fundus photography and electroretinography. Blood samples were collected from all participating family members, and genomic DNA was extracted. A genome-wide linkage scan was performed, followed by exclusion analyses among our cohort of nuclear consanguineous families with microsatellite markers spanning the TULP1 locus on chromosome 6p. Two-point logarithm of odds scores were calculated, and all coding exons of TULP1 were sequenced bidirectionally. The results of ophthalmological examinations among affected individuals in these 5 families were suggestive of retinitis pigmentosa. The genome-wide linkage scan localized the disease interval to chromosome 6p, harboring TULP1 in 1 of 5 families, and sequential analyses identified a single base pair substitution in TULP1 that results in threonine to alanine substitution (p.T380A). Subsequently, we investigated our entire cohort of families with autosomal recessive retinitis pigmentosa and identified 4 additional families with linkage to chromosome 6p, all of them harboring a single base pair substitution in TULP1 that results in lysine to arginine substitution (p.K489R). Results of single-nucleotide polymorphism haplotype analyses were suggestive of a common founder in these 4 families. Pathogenic mutations in TULP1 are responsible for the autosomal recessive retinitis pigmentosa phenotype in these consanguineous Pakistani families, with a single ancestral mutation in TULP1 causing the disease phenotype in 4 of 5 families. Clinical and molecular characterization of pathogenic mutations in TULP1 will increase our understanding of retinitis pigmentosa at a molecular level.Archives of ophthalmology 10/2011; 129(10):1351-7. · 3.86 Impact Factor -
Article: Ectopia lentis in a consanguineous pakistani family and a novel locus on chromosome 8q.
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ABSTRACT: To investigate the genetic basis and molecular characteristics of the isolated form of ectopia lentis. We ascertained a consanguineous Pakistani family with multiple individuals with ectopia lentis. All affected as well as unaffected members with isolated ectopia lentis underwent detailed ophthalmologic and medical examination. Blood samples were collected and DNA was extracted. A genome-wide scan was completed with 382 polymorphic microsatellite markers, and logarithm of odds (LOD) scores were calculated. Maximum 2-point LOD scores of 5.68 and 2.88 at theta = 0 were obtained for markers D8S285 and D8S260, respectively, during the genome-wide scan. Additional microsatellite markers refined the disease locus to a 16.96-cM (14.07-Mb) interval flanked by D8S1737 proximally and D8S1117 distally. We report on a new locus for nonsyndromic autosomal recessive ectopia lentis on chromosome 8q11.23-q13.2 in a consanguineous Pakistani family. Clinical Relevance Identification of genetic loci and genes involved in ectopia lentis will enhance our understanding of the disease at a molecular level, leading to better genetic counseling and family screening and possible future development of better treatment.Archives of ophthalmology 08/2010; 128(8):1046-9. · 3.86 Impact Factor -
Article: Mapping of a novel locus associated with autosomal recessive congenital cataract to chromosome 8p.
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ABSTRACT: To identify the disease locus for autosomal recessive congenital cataracts in a consanguineous Pakistani family. All affected individuals underwent a detailed ophthalmologic examination. Blood samples were collected and genomic DNA was extracted. A genome-wide scan was completed with fluorescently-labeled microsatellite markers on genomic DNA from affected and unaffected family members. Logarithms of odds (LOD) scores were calculated under a fully penetrant autosomal recessive model of inheritance. Ophthalmic examination suggested that affected individuals have bilateral cataracts. Linkage analysis localized the critical interval to chromosome 8p with LOD scores of 3.19, and 3.08 at θ=0, obtained with markers D8S549 and D8S550, respectively. Haplotype analyses refined the critical interval to 37.92 cM (16.28 Mb) region, flanked by markers, D8S277 proximally and D8S1734 distally. Here, we report a new locus for autosomal recessive congenital cataract mapped to chromosome 8p in a consanguineous Pakistani family.Molecular vision 01/2010; 16:2911-5. · 2.20 Impact Factor -
Article: Mapping of a new locus associated with autosomal recessive congenital cataract to chromosome 3q.
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ABSTRACT: To localize the disease interval for autosomal recessive congenital cataracts in a consanguineous Pakistani family. All affected individuals underwent detailed ophthalmologic examination. Blood samples were collected and genomic DNA was extracted. A genome-wide scan was performed with fluorescently-labeled microsatellite markers on genomic DNA from affected and unaffected family members and logarithm of odds (LOD) scores were calculated. Clinical records and ophthalmological examinations suggested that affected individuals have bilateral congenital cataracts. Genome-wide linkage analysis localized the critical interval to chromosome 3q with a maximum LOD score of 3.87 at θ=0; with marker D3S3609. Haplotype analyses refined the critical interval to a 23.39 cM (18.01 Mb) interval on chromosome 3q, flanked by D3S1614 proximally and D3S1262, distally. Here, we report a new locus for autosomal recessive congenital cataract localized to chromosome 3q in a consanguineous Pakistani family.Molecular vision 01/2010; 16:2634-8. · 2.20 Impact Factor -
Article: Autosomal recessive congenital cataract in consanguineous Pakistani families is associated with mutations in GALK1.
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ABSTRACT: To identify the pathogenic mutations responsible for autosomal recessive congenital cataracts in consanguineous Pakistani families. All affected individuals underwent detailed ophthalmologic and medical examination. Blood samples were collected and genomic DNA was extracted. A genome-wide scan was performed with polymorphic microsatellite markers on genomic DNA from affected and unaffected family members and logarithm of odds (LOD) scores were calculated. All coding exons of galactokinase (GALK1) were sequenced to identify pathogenic lesions. Clinical records and ophthalmological examinations suggested that affected individuals have nuclear cataracts. Linkage analysis localized the critical interval to chromosome 17q with a maximum LOD score of 5.54 at theta=0, with D17S785 in family PKCC030. Sequencing of GALK1, a gene present in the critical interval, identified a single base pair deletion: c.410delG, which results in a frame shift leading to a premature termination of GALK1: p.G137fsX27. Additionally, we identified a missense mutation: c.416T>C, in family PKCC055 that results in substitution of a leucine residue at position 139 with a proline residue: p.L139P, and is predicted to be deleterious to the native GALK1 structure. Here, we report pathogenic mutations in GALK1 that are responsible for autosomal recessive congenital cataracts in consanguineous Pakistani families.Molecular vision 01/2010; 16:682-8. · 2.20 Impact Factor -
Article: Autosomal recessive retinitis pigmentosa is associated with mutations in RP1 in three consanguineous Pakistani families.
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ABSTRACT: To localize and identify the gene and mutations causing autosomal recessive retinitis pigmentosa in three consanguineous Pakistani families. Blood samples were collected and DNA was extracted. A genome-wide scan was performed by using 382 polymorphic microsatellite markers on genomic DNA from affected and unaffected family members, and lod scores were calculated. A genome-wide scan of 25 families gave an hlod = 4.53 with D8S260. Retinitis pigmentosa in all three families mapped to a 14.21-cM (21.19-Mb) region on chromosome 8 at q11, flanked by D8S532 and D8S260. This region harbors RP1, which is known to cause autosomal dominant retinitis pigmentosa. Sequencing of the coding exons of RP1 showed mutations in all three families: two single-base deletions, c.4703delA and c.5400delA, resulting in a frame shift, and a 4-bp insertion, c.1606insTGAA, all causing premature termination of the protein. All affected individuals in these families are homozygous for the mutations. Parents and siblings heterozygous for the mutant allele did not show any signs or symptoms of RP. These results provide strong evidence that mutations in RP1 can result in recessive as well as dominant retinitis pigmentosa. The findings suggest that truncation of RP1 before the BIF motif or within the terminal portion results in a simple loss of RP1 function, producing a recessive inheritance pattern. In contrast, disruption of RP1 within or immediately after the BIF domain may result in a protein with a deleterious effect and hence a dominant inheritance pattern.Investigative Ophthalmology & Visual Science 08/2005; 46(7):2264-70. · 3.60 Impact Factor
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Institutions
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2010–2011
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University of the Punjab
- Centre for Excellence in Molecular Biology
Lahore, Punjab, Pakistan
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