Myopia is described as the common cause of impaired vision and visual disability. In this disease the image is not focused sharply on the retina causing a blur vision to be formed and this condition of eye is referred as myopia. It is highly prevalent eye disease with its prevalence estimated to be I trillion throughout the world and approximately four billion in Pakistan. It is multi factorial disease with 19 loci identified up to date. Five myopic families were identified and selected for this study from different areas of Lahore. Linkage analysis of these families was done by MYP3, MYP4 and MYP5 loci (each consisting of a set of 3 microsatellite markers) of myopia that were selected from the panel of 19 loci. A total number of 9 microsatellite markers were used to analyze 24 samples from five families. After DNA extraction and PCR amplification, linkage analysis was carried out by genotyping through PAGE and haplotypes were constructed for the families.

Through the haplotype analysis of pedigree it was found that none of the families was found linked on any of the loci. The comparison of linkage analysis past studies with this study yielded no evidence for the presence of linkage in any of the family genotypes on the three loci. Also the LOD score calculation suggested that as all the pedigrees were found to be unlinked, the LOD score values calculated was less than 1 which suggests that markers also do not support the linkage. This may be due to the less availability of normal samples and total number of affected samples.

Moreover according to clinical factors, the individuals selected had low cylindrical component which suggest that these individuals are having simple to moderate myopia. Whereas, increase in spherical component with age shifts the lens more towards positive value (hyperopia) was also observed.

It is concluded from this study that no linkage was identified in any of the family. Both clinical and genetic factors are involved in development of myopia. Further detail study on the loci of myopia is required especially focusing the families with consanguineous marriages. Because in such families the probability of presence of linkage is more as the chances of transmission of disease allele are more in cousin marriages. From the presence of unlinked pedigrees it can also be proposed that any novel locus is present and through the identification of this novel locus, a novel gene can also be identified. Moreover, there is a probability that through genome wide screening, any other loci on any other families of Lahore may show an inherited pattern.