Human genetics is one of the most fascinating studies that provide the better understanding towards human beings. The study of human genetics unveils the factors responsible for human diseases. In recent times, scientists have overcome the complexity of some rare genetic disorders. Several genes seem to be involved in genetic diseases. In order to correlate genotype with phenotype of genetic disorders, studies were carried out to determine nucleotide diversity among individuals. Variation in the DNA sequence of a gene is one of the several factors held responsible for rare diseases and they arise due to the mutations.
While mutation is defined by alteration in DNA sequence that changes the function of the gene, single nucleotide polymorphism (SNP) is the most common form of genetic variation that occurs 1 in 1000 base pairs in which nucleotide differs only at one position of the DNA sequence. Till now, approx. 11 million SNPs have been reported in the human genome. Out of these, around 60,000 are found to be present in coding and regulatory regions. They may alter the structure or function of DNA by influencing the promoter activity or conformation of pre-mRNA. SNPs might play a direct or indirect role in genetic disorder.