Analysis of Genetic Variation of rs1542705 Marker in SMPD1 Gene Region as an Informative Marker for Molecular Diagnosis of Niemann-Pick Disease in Isfahan Population

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.
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.
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.
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.