Background: IFN-&lambda3 (IL-28B) is a new cytokine from the type III interferons. Its role in several biologic activities, such as regulation of immune responses, tumor and metastasis, or its functions in HBV and HCV diseases, has been shown. The present study evaluated the frequency of rs8099917 allele polymorphism in IFN-&lambda3 gene in Iranian population.

Materials and Methods: In this laboratory-experimental study, after collecting blood samples from 118 unrelated Iranian subjects, DNA extraction was performed according to the kit protocols. Evaluation of rs8099917 allele polymorphism was done by Nested-PCR and RFLP method using BsrDI and Tsp451 restriction enzymes.

Results: After running the tests and data analysis, the frequencies of GG genotype (2.5%), GT genotype (31.4%), and TT genotype (66.1%) were obtained. Allele frequencies were 71.22% for G allele and 81.78% for T allele.

Conclusion: The results of this study showed that TT genotype and T allele are the dominant frequencies of rs8099917 allele of IFN-&lambda3 gene in Iranian population. Regarding the different established functions of IFN-&lambda3, frequency determination of this variant can be helpful in different studies, designs, evaluations, and treatment procedures in some diseases, such as tumors and hepatitis, in Iranian patients.

Background: Niemann-Pick disease (NPD) refers to a group of lysosomal storage diseases that causes abnormal metabolism of lipids. One of the genes that play a role in the pathogenesis of this disease is SMPD1. To date, more than hundred disease- causing mutations have been identified in SMPD1 gene. Due to the large number of mutations in this gene, direct analysis of the mutations is costly and time-consuming. Therefore, indirect linkage analysis using polymorphic markers as an alternative method for molecular diagnosis of the mutations has been recommended. In the present study, allele frequency of rs1542705 genetic marker was analyzed in the Iranian population. The aim was to determine the polymorphic information content (PIC) and the possibility of its application in indirect diagnosing of NPD.

Materials and Methods: After bioinformatics analysis of the SMPD1 gene region, rs1542705 marker was selected for genotyping in Isfahan population. In order to calculate the allele and genotype frequency of the marker, molecular tests were done on 113 DNA samples of unrelated healthy individuals by using ARMS-PCR technique. Finally, the information related to the genotype of the individuals was statistically analyzed using Powermarker and Genepop software.

Results: The analyses showed that the studied population was in accordance with Hardy-Weinberg equilibrium. Allele frequency of rs1542705 marker for T and C alleles was 71.24% and 28.76%, respectively, and the heterozygosity of the marker was 43.36%. Also, polymorphic information content (PIC) was 0.325.

Conclusion: The results of this study showed that rs1542705 marker could be considered as an informative marker for molecular diagnosis of Niemann- Pick disease using linkage analysis in the studied population.