Primary microcephaly (MCPH) is neurological disorder. It exhibits genetic heterogeneity. The genes identified in MCPH are Microcephalin gene at MCPH1 locus, WDR62 at MCPH2, CDK5RAP2 gene at MCPH3 locus, CEP152 at MCPH4, ASPM at MCPH5 locus, CENPJ at MCPH6 locus and STIL/SIL at MCPH7 locus. The objective of this study was to identify families from Punjab and to perform homozygosity mapping and DNA sequencing for mutation detection. We reported c.3978GA; p.W1326X mutation in ASPM gene of MCPH families from Punjab. This is the most prevalent gene investigated for mutations in Pakistan. The identification of common mutation in ASPM gene in families with primary microcephaly analyzed in this study from Punjab and several other families of an apparently different ethnic group (Pashtun) revealed most probable involvement of common ancestry for this variant in these MCPH families. Further data should be explored so that centres for genetic counseling could be established to guide the people for avoiding blood relation marraiges.