Article

Genomic structure and organization of the high grade Myopia-2 locus (MYP2) critical region: mutation screening of 9 positional candidate genes

Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
Molecular vision (Impact Factor: 2.25). 03/2005; 11:97-110.
Source: PubMed

ABSTRACT Myopia is a common complex eye disorder, with implications for blindness due to increased risk of retinal detachment, chorioretinal degeneration, premature cataracts, and glaucoma. A genomic interval of 2.2 centiMorgans (cM) was defined on chromosome band 18p11.31 using 7 families diagnosed with autosomal dominant high myopia and was designated the MYP2 locus. To characterize this region, we analyzed 9 known candidate genes localized to within the 2.2 cM interval by direct sequencing.
Using public databases, a physical map of the MYP2 interval was compiled. Gene expression studies in ocular tissues using complementary DNA library screens, microarray experiments, reverse transcription techniques, and expression data identified in external databases aided in prioritizing gene selection for screening. Coding regions, intron-exon boundaries and untranslated exons of all known genes [Clusterin-like 1 (CLUL1), elastin microfibril interfacer 2 (EMILIN2), lipin 2 (LPIN2), myomesin 1 (MYOM1), myosin regulatory light chain 3 (MRCL3), myosin regulatory light chain 2 (MRLC2), transforming growth beta-induced factor (TGIFbeta), large Drosophila homolog associated protein 1 (DLGAP1), and zinc finger protein 161 homolog (ZFP161)] were sequenced using genomic DNA samples from 9 affected and 6 unaffected MYP2 pedigree members, and from 5 external controls (4 unaffected and 1 affected). Gene sequence changes were compared to known variants from public single nucleotide polymorphism (SNP) databases.
In total, 103 polymorphisms were found by direct sequencing; 10 were missense, 14 were silent, 26 were not translated, 49 were intronic, 1 insertion, and 3 were homozygous deletions. Twenty-seven polymorphisms were novel. Novel SNPs were submitted to the public database; observed frequencies were submitted for known SNPs. No sequence alterations segregated with the disease phenotype.
Mutation analysis of 9 encoded positional candidate genes on MYP2 loci did not identify sequence alterations associated with the disease phenotype. Further studies of MYP2 candidate genes, including analysis of putative genes predicted in silico, are underway.

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    • "All genes that map within the MYP2 critical region are candidate disease genes based on position. Coding regions, intron-exon boundaries and untranslated exons of Clusterin-like 1 (CLUL1), elastin microfibril interfacer 2 (EMILIN2), lipin 2 (LPIN2), myomesin 1 (MYOM1), myosin regulatory light chain 3 (MRCL3), myosin regulatory light chain 2 (MRLC2), transforming growth β-induced factor (TGIFβ), large Drosophila homolog associated protein 1 (DLGAP1), and zinc finger protein 161 homolog (ZFP161) were sequenced, but mutation analysis did not identify sequence alterations associated with high myopia [11]. The direct analysis of sequence within a critical region can be the most accurate, precise and efficient approach to disease gene identification. "
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    ABSTRACT: High myopia is a severe hereditary ocular disease leading to blindness. LAMA1 (alpha subunit of laminin) is a promising candidate gene for high myopia present in the MYP2 (myopia 2) region. The purpose of this study was to determine if high myopia is associated with single nucleotide polymorphism (SNP) variants in LAMA1 in Chinese subjects. Ninety-seven Chinese subjects with high myopia and ethnically and sexually matched 103 normal controls were enrolled. Genomic DNA was prepared from peripheral blood. The 5 SNPs of LAMA1 were analyzed using PCR and SNaPshot. Allele frequencies were tested for Hardy-Weinberg disequilibrium. The genotype and allele frequencies were evaluated using the χ(2) tests or the Fisher exact tests. One of the 5 SNPs showed a significant difference between patients and control subjects (rs2089760: p(genotype)=0.005, p(allel)=0.003). There were no statistically significant differences between patients and control subjects for the other four SNPs: rs566655, rs11664063, rs607230, and rs3810046. Our results indicate that the polymorphism of rs2089760, located in the promoter region of LAMA1, may be associated with high myopia in the Chinese population and should be investigated further.
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    • "Emilin2 mRNA expression has been reported in spleen and uterus (Braghetta et al. 2004); fetal heart, lung, placenta, and peripheral leukocytes (Doliana et al. 2001); cochlear basement membrane (Amma et al. 2003); and optic tissues (Scavello et al. 2005). Emilin2 is expressed in the vasculature and heart in zebrafish during embryonic development and in adults (Milanetto et al. 2008). "
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    • "1 (CLUL1), elastin microfi brial interfacer 2 (EMILIN2), lipin 2 (LPIN2), myomesin 1 (MYOM1), myosin regulatory light chain 3 (MIRCL3), myosin regulatory light chain 2 (MRLC2), transforming growth β-induced factor (TGIFβ), large Drosophila homolog association protein 1 (DLGPA1), and zinc fi nger protein 161 homolog (ZFP161). Scavello et al (2005) "
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    ABSTRACT: Although a myopia susceptibility gene has not yet been elucidated, ten candidate regions (MYP1-MYP10) have been associated with myopia by linkage analysis employing large pedigrees. We report herein on the results of our analysis pertaining to polymorphisms of LAMA1 (alpha subunit of laminin), a promising candidate gene for high myopia present in the MYP2 region of Japanese subjects with high myopia. Three hundred and thirty Japanese subjects with high myopia at a level of greater than -9.25 D and ethnically and sex matched 330 normal controls without high myopia was enrolled in this study. The thirteen SNPs located on the LAMA1 gene were analyzed using PCR and SNP-specific fluorogenic probes. Two of the SNPs were monomorphic and none of the 11 SNPs showed statistically significant association with high myopia in the Japanese population. There is no convincing evidence to prove a connection between nucleotide sequence variations in LAMA1 and high myopia. The pairwise linkage disequilibrium (LD) mapping disclosed a strong value (D' > 0.8) and narrow ranged block within these SNPs.
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