Gharaibeh et al. (2014) studied 50 consecutive patients with retinitis pigmentosa and 50 controls matched by age and gender to determine the prevalence of thrombophilic factors. Among patients/controls they found the PAI-1 4G/5G (40/48) and PAI-1 GA844 (50/52) heterozygous mutations. Gharaibeh et al. (2014) concluded that the difference between patients with retinitis pigmentosa and the control group was not statistically significant for the prevalence of this studied factor.

Mammo et al. (2007) reported the incidences of five prothrombotic gene polymorphisms among Saudi Arabians. The data for this study came from the Saudi Thrombosis and Familial Thrombophilia Registry. The subjects were healthy consenting donors from different regions, tribes, and origins in Saudi Arabia. Between 2001 and 2005, DNA samples from 902 Saudis (793 men and 109 women) were collected and genotyped. The PAI-1 4G/5G mutation was tested in 651 of these subjects. Heterozygous carrier rate for this mutation was found to be 51%, while 10% of the subjects were homozygous rare allele carriers. The incidence of the rare allele was 61% (frequency 36%).

The 4G/4G polymorphism of plasminogen activator inhibitor (PAI1) gene, which is associated with higher plasma PAI1 activity, is a genetic risk factor of coronary heart disease. This may contribute for the high prevalence of cardiovascular death in patients with progressive renal disease. This triggered Al-Muhann et al. (2008) to determine the prevalence of this polymorphism in Saudi patients with end-stage renal disease (ESRD) on hemodialysis. The control group only included people with no past, present or family history of renal disease. The allele frequency and homozygous genotype of 4G/4G of the PAI1 gene polymorphism were 46% and 5% respectively in patients compared to 57% and 32% respectively in the control group. The prevalence of PAI-1 4G/4G polymorphism in ESRD patients was lower than the control group, and, hence, it may play a part in the abovementioned cardiovascular complications.