Clinical features of children with atopic dermatitis according to filaggrin gene variants

Background: Filament aggregating protein (Filaggrin) is a skeletal cell component that provides a protective function for the epidermis. Mutations of the filaggrin gene (FLG) cause a loss of filaggrin protein. These mutations are seen in 50% of atopic dermatitis (AD). The aim of the study was to investigate the polymorphisms and mutations of the FLG in Iranian children with AD. Materials and methods: This project was a case-controlled study with 25 children diagnosed with AD as the case group and 25 healthy children as the control group. Demographic data, clinical manifestations, and filaggrin single nucleotide polymorphisms (SNPs) and mutations were recorded. Blood samples were collected for the immunoglobulin E (IgE) assay and complete blood count tests. Results: We found a significant association between the presence of polymorphism (rs66831674) and patients’ age, and polymorphism (rs41267154) and early onset of AD. We found no significant differences between the FLG polymorphisms with respect to the severity of AD, ethnicity, concurrent allergic diseases, eosinophilia, and IgE serum levels. Conclusion: Interestingly, FLG variants (rs66831674 and rs41267154) were associated with age and early onset of AD. However, additional studies are required to confirm these results on a large scale of Iranian population. Moreover, establishing a cohort prospective study is suggested to assess the progression of other atopic disorders based on FLG polymorphisms (AU)

Identification of eleven different mutations including six novel, in the arylsulfatase B gene in Iranian patients with mucopolysaccharidosis type VI.

Mucopolysaccharidosis VI is a rare autosomal recessive disorder caused by the deficiency of enzyme Arylsulfatase B. The enzyme deficiency leads to the accumulation of dermatan sulfate in connective tissue which causes manifestations related to MPS VI. Up to now, three different disease causing variants are reported in Iranian patients. In this study, we scanned ARSB gene of 13 Iranian patients from 12 families in whom all parents were consanguineous and from the same ethnicity except one family that were not consanguineous but co-ethnic. We found six not previously reported disease causing variants. We extracted DNA from peripheral blood samples of patients that were previously confirmed as MPS VI by clinical, biochemical and enzymatic assays including berry-spot test and fluorimetry, followed by PCR and direct sequencing. Computational approaches were used to analyze novel variants in terms of their impact on the protein structure. 11 disease causing variants and 15 polymorphisms were found. Six disease causing variants were novel and five were previously reported of which three were in Iranian population. Four of patients, who were unrelated, two by two had the same disease causing variant and polymorphisms, which indicates a possible founder effect. Our study also implicates genotype-phenotype correlation. Computational structural modeling indicated these disease causing variants might affect structural stability and function of the protein. Data of this study confirms the existence of mutational heterogeneity in the ARSB between Iranian patients. Disease causing variants with high frequency can be used in the prenatal diagnosis and genetic counseling. Also, the existence of the same variants and polymorphisms in some of the unrelated patients indicates a possible founder effect.

Genetic Analysis of 13 Iranian Families With Leukocyte Adhesion Deficiency Type 1.

BACKGROUND AND AIM: Leukocyte adhesion deficiency type 1 is a rare, autosomal recessive disorder that results from mutations in the ITGB2 gene. This gene encodes the CD18 subunit of ß2 integrin leukocyte adhesion cell molecules. Leukocyte adhesion deficiency type 1 is characterized by recurrent bacterial infections, impaired wound healing, inadequate pus formation, and delayed separation of the umbilical cord. MATERIALS AND METHODS: Blood samples were taken from 13 patients after written consent had been obtained. Genomic DNA was extracted, and ITGB2 exons and exon-intron boundaries were amplified by polymerase chain reaction. The products were examined by Sanger sequencing. RESULTS: In this study, 8 different previously reported mutations (intron7+1G>A, c.715G>A, c.1777 C>T, c.843del C, c.1768T>C, c.1821C>A, Intron7+1G>A, c.1885G>A) and 2 novel mutations (c.1821C>A; p.Tyr607Ter and c.1822C>T; p.Gln608Ter) were found. CONCLUSIONS: c.1821C>A (p.Tyr607Ter) and c.1822C>T (p.Gln608Ter) mutations should be included in the panel of carrier detection and prenatal diagnosis.

Filaggrin gene polymorphisms in Iranian ichthyosis vulgaris and atopic dermatitis patients.

BACKGROUND: Filaggrin is a key structural epidermal protein in terminal differentiation and formation of skin barrier. The important role of filaggrin and its effects in various cutaneous and noncutaneous disorders initiated a cascade of considerable research in recent years. Loss-of-function mutations in FLG, the human gene encoding profilaggrin/filaggrin, is the cause of the common skin condition ichthyosis vulgaris (IV) and major genetic predisposing factor for atopic dermatitis (AD). Several null mutations in the FLG gene that lead to a decrease or absence of filaggrin in skin and predispose these conditions have been described. OBJECTIVE: The aim of this study was to investigative genetic polymorphism of FLG in Iranian patients with IV and AD. METHODS: In the current study, we carried out full sequencing of the entire FLG coding region in 30 IV patients and 30 AD patients, and also 60 healthy controls. RESULTS: In our research, we identified 43 variants reported previously and two novel variants. CONCLUSION: In our study, in the AD and IV patients, loss-of-function FLG mutation was not found. This means that another mechanism other than FLG nonsense mutation is involved in the pathogenesis of these patients.

Characterization of 4 New Mutations in the CYBB Gene in 10 Iranian Families With X-linked Chronic Granulomatous Disease.

Chronic granulomatous disease (CGD) is an inherited disease of the innate immune system that results from defects in 1 of the 5 subunits of nicotinamide adenine dinucleotide phosphate oxidase complex and leads to life-threatening infections with granuloma formation. During 3 years of study, we recognized 10 male patients with X-linked CGD from a tertiary referral center for immune deficiencies in Iran. The CGD patients were diagnosed according to clinical features and biochemical tests, including nitroblue tetrazolium and dihydrorhodamine-1, 2, 3 tests, performed on patients and their mothers. In all patients, Western blot analysis showed a gp91 phenotype. Mutation screening by single strand conformation polymorphism and multiplex ligation-dependent probe amplification analysis of the CYBB gene encoding gp91, followed by sequencing, showed 9 different mutations, 4 of them novel as far as we know.

Mutation characterization and heterodimer analysis of patients with leukocyte adhesion deficiency: Including one novel mutation.

BACKGROUND AND AIM: Leukocyte adhesion deficiency type 1 (LAD-I) is a rare, autosomal recessive disorder of neutrophil migration, characterized by severe, recurrent bacterial infections, inadequate pus formation and impaired wound healing. The ITGB2 gene encodes the ß2 integrin subunit (CD18) of the leukocyte adhesion cell molecules, and mutations in this gene cause LAD-I. The aim of the current study was to investigate the mutations in patients diagnosed with LAD-I and functional studies of the impact of two previously reported and a novel mutation on the expression of the CD18/CD11a heterodimer. MATERIALS AND METHODS: Blood samples were taken from three patients who had signed the consent form. Genomic DNA was extracted and ITGB2 exons and flanking intronic regions were amplified by polymerase chain reaction. Mutation screening was performed after Sanger sequencing of PCR products. For functional studies, COS-7 cells were co-transfected with an expression vector containing cDNA encoding mutant CD18 proteins and normal CD11a. Flow cytometry analysis of CD18/CD11a expression was assessed by dimer-specific IB4 monoclonal antibody. RESULTS: Two previously reported mutations and one novel mutation,p. Cys562Tyr, were found. All mutations reduced CD18/CD11 heterodimer expression. CONCLUSION: Our strategy recognized the p.Cys562Tyr mutation as a pathogenic alteration that does not support CD18 heterodimer formation. Therefore, it can be put into a panel of carrier and prenatal diagnosis programs.

BAK, BAX, and NBK/BIK proapoptotic gene alterations in Iranian patients with ataxia telangiectasia.

INTRODUCTION: Ataxia telangiectasia (AT) is an autosomal recessive multisystem disorder characterized by variable immunodeficiency, progressive neurodegeneration, occulocutaneous telangiectasia, and an increased susceptibility to malignancies. This study was designed to study the role of proapoptotic BAK, BAX, and NBK/BIK genes in a group of patients with AT to elucidate the possible role of these genes in progression of malignancies in this disease. MATERIALS AND METHODS: Fifty Iranian patients with AT were investigated in this study. The entire coding regions of the BAK gene (exons 2-6), NBK/BIK gene (exons 2-5), and BAX gene (exons 1-7) were amplified using polymerase chain reaction (PCR). The PCR products were separated by 2% agarose gel electrophoresis, and all positive samples were verified by direct sequencing of PCR products using the same primers used for PCR amplification, BigDye chemistry, and Avent 3100 Genetic Analyzer following the manufacturer's instructions (Applied Biosystems). RESULTS: Eight of fifty Iranian AT patients (16%) exhibited a C > T transition in exon 2 (c342C > T) of the BAK gene, while none of the healthy controls had such alteration (P = 0.0001). Higher frequency of another nucleotide substitution in the noncoding region of exon 7 in BAX gene (6855G > A) was also identified in 68% of the patient group versus 24% in the controls (P < 0.0001). Sequence alteration in intronic region of the NBK/BIK gene IVS4-12delTC was observed in 52% of AT patients, which was significantly higher than 20% in the control group (P = 0.0023). Another variant IVS1146C > T in the intronic region of the BAX gene was found in 78% of patients, which was significantly higher than 10% in the controls (P < 0.0001). Frequency of alteration in intronic region of exon 3 of the BAX gene (IVS3 + 14A > G) was also significantly higher in the AT patients (P < 0.0001). DISCUSSION: Several alterations in the proapoptotic genes BAK, NBK/BIK, and BAX were found in our study, which could elucidate involvement of the mitochondrial pathway mediated apoptosis in accelerating and developing of cancers and in immunopathogenesis of AT. Such altered apoptosis in AT could play some roles in developing cancers in this group of patients.

Use of D11S2179 and D11S1343 as markers for prenatal diagnosis of ataxia telangiectasia in Iranian patients.

Ataxia telangiectasia (AT) is an autosomal recessive disorder with an estimated prevalence of 1/40,000 to 1/100,000 in reported populations. There is a 25% possibility for having an affected child when parents are carriers for the ATM gene mutation. There is no cure available for this disease and prenatal testing is strongly recommended for prevention of this disease. Although the preferred method is the direct mutation analysis of the ATM gene, the large size of the ATM gene with 63 exons and the large number of possible mutations in patients considerably limit efficiency of mutation analysis as a diagnostic choice. Indirect method is a better tool when parents are not carriers of founder mutation and pass different mutations to their children. Indirect molecular diagnosis using ATM-related molecular markers facilitates prenatal diagnosis of AT children. In this study, four molecular markers: D11S2179, D11S1787, D11S535, D11S1343 are genotyped in 19 unrelated families from different regions of Iran. Those markers are amplified using extracted sequence primers from the Gene Bank with their described PCR conditions. Amplified products were separated using denaturing PAGE gels, and data were analyzed to detect their pattern of inheritance in each family. In all families, segregation of alleles was according to Mendelian inheritance, and affected chromosomes were distinguishable from unaffected ones. All carriers and affected patients were diagnosed accurately. Thus, this method is effectively useful in prenatal diagnosis of AT.

DNA banking of primary immunodeficiency disorders in iran.

Primary immunodeficiency disorders are a heterogeneous group of genetic disorders, with different modes of inheritance, consisting of more than 100 different types. We constructed the DNA banking of primary immunodeficiency disorders for the first time in Iran. The DNA of 31 immunodeficient patients and their families (total of 92 samples) were collected, as the first step for construction of DNA banking. DNA was isolated from whole blood by salting out method. Among our patients, Common variable immunodeficiency was the most common disorder, followed by X-linked agammaglobulinemia, Ataxia-telangiectasia, Chronic granulomatous disease, Severe combined immunodeficiency, Hyper IgM syndromes, and Leukocyte adhesion defects. DNA banking is a useful method for further detection of mutation in immunodeficient patients and prenatal diagnosis for presence or absence of the disorder in the fetus which can be confirmed by molecular genetics testing.

ATM Gene Mutations Detection in Iranian Ataxia-Telangiectasia Patients.

Ataxia-Telangiectasia (AT) is an autosomal recessive disorder involving cerebellar degeneration, immunodeficiency, radiation sensitivity and cancer predisposition. The ATM gene on human chromosome 11q22.3 has recently been identified as the gene responsible for ataxia-telangiectasia (AT). The gene mutated in AT, which has been designated as the ATM gene, encodes a large protein kinase with a PI-3 kinase-related domain. More than 100 mutations are broadly distributed throughout the ATM gene. The large size of the ATM gene (66 exons spanning ~150kb of genomic DNA) together with the diversity and broad distribution of mutations in AT patients, greatly limits the utility of direct mutation screening as a diagnostic tool. In this study, 20 families with at least one affected child clinically suspected to have ataxia-telangiectasia were examined and their DNA was extracted and amplified with standard methods. Sequencing methods were used to detect the new point mutation. Four exons which were hot spots for point mutations in ATM gene were detected by PCR-SSCP or PCR-RFLP.

Comparison of two proliferation assays MTT and ltt in immunodeficient patients.

MTT assay is designed for spectrophotometric quantification of cell growth and viability without using the radiactive isotopes. The aim of this study is comparison of LIT and MTT as sensitive poliferation assays in imrnunodeficient patients. 20 immunodeficient and 20 healthy subjects were selected in this study. All of them had normal lymphocytes count, normal CD3 and negative DIR reaction to PPD, DT and candida. The immunodeficient patients regularly suffered from herpes, candida and staph abscess. The lymphocytes of inimunodeficient control groups were treated with PHA as mitogen. The lymphocyte proliferation was evaluated by MTT and LTT. The results showed a strong correlation between LTT and MITT between immunodeficient patients and healthy controls. The sensitivity test for MTT was 90%, and the sensitivity test for LTT was 98%. MTT method can be considered as a non-radiactive evaluation of cell proliferation. Detecting cell proliferation with accurate, sensitive, fast, easy and safe method is more preferable than LTT.