PROS1 and hyperinsulinemic hypoglycemia, familial, 4: This is similar to the finding of a higher incidence of protein S deficiency among patients with CD4 cell counts of < 200 cells/μL in a study by Lijfering et al.19 Ahonkai et al. also reported an increased prevalence of deep venous thrombosis in HIV-infected subjects with CD4 cell counts of < 500 cells/μL.20 These findings suggest that continuous viral replication in treatment-naïve HIV-infected individuals may increase the risk of venous thrombosis.21