Introduction: Tay-Sachs is a genetic disorder with autosomal recessive inheritance affecting the central nervous system. The disorder mainly results from mutations in the HEXA gene on chromosome 15. Sequencing is used to detect mutations and sequence variations in the HEXA gene, which is expensive and time consuming. Alternatively, linkage analysis of polymorphic markers such as single nucleotide polymorphism (SNP) could be used in heterozygous carrier detection and prenatal diagnosis of the disease in families with an affected individual.

Materials & methods: A large number of SNP markers have been introduced for the HEXA gene in the electronic databases. In the present study the genotype and informative situation of rs2288258 genetic marker in HEXA gene region was investigated using Tetra-primer ARMS PCR technique with newly designed primers in Isfahan population. Estimation of allelic frequency, genotype frequency, presence of Hardy Weinberg Equilibrium (HWE) and the amount of polymorphism information content (PIC) was computed by Power Marker software.

Findings: The results indicated 9.12% minor allele frequency (MAF) and PIC=0.1520 for rs2288258 marker in the Isfahan population. Also, analysis of Hardy-Weinberg Equilibrium showed the presence of equilibrium for this marker in the mentioned population.

Discussion & conclusions: The results indicated 9.12% minor allele frequency (MAF) and PIC=0.1520 for rs2288258 marker in the Isfahan population. Also, analysis of Hardy-Weinberg Equilibrium showed the presence of equilibrium for this marker in the mentioned population. Totally, according to the results of this study rs2288258 genetic marker could be introduced as an SNP marker for linkage analysis in carrier detection and prenatal diagnosis of HEXA mutations in Isfahan population.

Introduction: Niemann Pick Disease (NPD) is a lipid storage disorder with an autosomal recessive inheritance. The disease occurs mainly due to defects in SMPD1 gene (11p15.4), encoding sphingomyelinase. Disruption of this enzyme leads to the accumulation of sphingomyelin in brain and liver resulting in dysfunction or damage of the brain tissues.
 
Polymorphic markers such as Single Nucleotide Polymorphisms (SNPs) are used in molecular diagnosis of genetic disease through linkage analysis or homozygosity mapping. The allele frequency and degree of heterozygosity of the markers are usually population dependent. The aim of this study was to investigate the allele frequency and degree hetereozygosity of rs67992843 marker located in the SMPD1 gene region in the Iranian population.
 
Materials & methods: 113 unrelated individuals were selected for this study. The marker was genotyped using ARMS PCR with newly designed primers. The results were analyzed by Genepop database and Power Marker software to estimate allelic frequency, heterozygosity rate, presence of Hardy Weinberg Equilibrium (HWE) and polymorphism information content (PIC).
 
Findings: The data showed 31.42% Minor Allele Frequency (MAF), 39.82% heterozygosity rate and PIC 0.338 for rs67992843 marker in the Iranian population.
 
Discussion & conclusions: The results of this study showed that rs67992843 marker could be suggested for linkage analysis and molecular diagnosis of SMPD1 gene in the Iranian population.