Mutation Analysis of the ADAR1 Gene in Dyschromatosis Symmetrica Hereditaria and Genetic Differentiation from both Dyschromatosis Universalis Hereditaria and Acropigmentatio Reticularis

Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Journal of Investigative Dermatology (Impact Factor: 7.22). 07/2005; 124(6):1186-92. DOI: 10.1111/j.0022-202X.2005.23732.x
Source: PubMed


Dyschromatosis symmetrica hereditaria (DSH) (also called "reticulate acropigmentation of Dohi") is a pigmentary genodermatosis of autosomal dominant inheritance. We have clarified for the first time four pathological mutations of the double-stranded RNA-specific adenosine deaminase gene (ADAR1 or DSRAD) in four DSH pedigrees. In this paper, we report 16 novel mutations containing six missense substitutions (p.V906F, p.K1003R, p.G1007R, p.C1036S, p.S1064F, p.R1078C), two splice site mutations (IVS2+2T>G, IVS8+2T>A), six frameshift mutations (p.H216fs, p.K433fs, p.G507fs, p.P727fs, p.V955fs, p.K1201fs), and two nonsense mutations (p.R426X, p.Q600X) found in Japanese patients with DSH. We did not establish any clear correlation between the clinical phenotypes and the genotypes of ADAR1 gene mutations in our examination of 16 cases plus four pedigrees. None of the different mutations identified in our studies of 20 cases suggested any founder effect. Furthermore, we did not identify any mutations in the ADAR1 gene of three patients with dyschromatosis universalis hereditaria or three patients with acropigmentatio reticularis, indicating that the two diseases are completely different from DSH, although they have sometimes been suggested to be phenotypical variations of DSH.

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Available from: Kazuyoshi Fukai, Apr 08, 2014
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    • "Driven by different promoter, ADAR1 has been characterized into two isoforms, an interferon-inducible 150 kDa protein (p150) and a constitutively-expressed 110 kDa protein (p110), in mammalian cells [1,2]. The p150 isoform, translated from the methionine initiation codon, is the full length protein mainly distributed in cytosol while the p110 isoform initially translates from the AUG at codon 296 and locates in the nucleus [28]. Till now, including p.Gln186X identified in our study, four mutations of ADAR1 have been reported at the 5′ side of codon 296 [2,29]. "
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    ABSTRACT: Background Dyschromatosis symmetrica hereditaria (DSH) is an autosomal dominantly inherited skin disease associated with mutations of ADAR1, the gene that encodes a double-stranded RNA-specific adenosine deaminase. The purpose of this study was to investigate the potential mutations in ADAR1 in seven Chinese families with DSH. Methods All the coding exons including adjacent intronic as well as 5′ and 3′ untranslated region (UTR) of ADAR1 were screened by direct sequencing. Moreover, quantitative reverse-transcription polymerase chain (qRT-PCR) and Western blot were applied to determine the pathogenic effects associated with the mutations. Results Molecular genetic investigations detected five novel mutations (c.556C > T, c.3001C > T, c.1936_1937insTG, c.1065_1068delGACA and c.1601G > A resulting in p.Gln186X, p.Arg1001Cys, p.Phe646LeufsX16, p.Asp357ArgfsX47 and p.Gly471AspfsX30 protein changes, respectively) as well as two previously reported (c.2744C > T and c.3463C > T causing p.Ser915Phe and p.Arg1155Trp protein changes, respectively). Among them, we found that the substitution c.1601G > A at the last nucleotide of exon 2 compromised the recognition of the splice donor site of intron 2, inducing an aberrant transcript with 190-bp deletion in exon 2 and causing an approximately 50% reduction of ADAR1 mRNA level in affected individual. In addition, consistent with the predicted results, the expression patterns of other novel mutations were detected by Western blot. Conclusion We identified five novel and two recurrent mutations of the ADAR1 gene in seven Chinese families with DSH and investigated potential effects of the novel mutations in this study. Our study expands the database on mutations of ADAR1 and for the first time, demonstrates the importance of exonic nucleotides at exon-intron junctions for ADAR1 splicing.
    Full-text · Article · Jun 2014 · BMC Medical Genetics
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    • "The two mutations of p.Q102fs reported in this study and p.H216fs reported previously (Suzuki et al., 2005) are located at the 5 0 side of codon 296 which is the translation initiation codon for hADAR1-p110 (Figure 1). Therefore, they must cause frameshift changes in the synthesis of hADAR1-p150, "
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    ABSTRACT: Dyschromatosis symmetrica hereditaria (DSH) is a pigmentary genodermatosis of autosomal-dominant inheritance. We have reported 20 different mutations of the adenosine deaminase acting on RNA 1 gene (ADAR1) in patients with DSH since we had clarified that the disease is caused by a mutation of the ADAR1 gene in 2003. In this study, we report 10 novel mutations responsible for DSH: p.Q102fsX123, p.T369fsX374, p.S664fsX677, p.R892L, p.I913R, p.R916Q, p.P990fsX1016, p.C1081S, p.C1169F, and p.K1187X.
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