introduction : according to drug gateway theory, smoking cigarette, especially, low onset age of smoking, is one of the risk factors for future use. objective the present study deals with comparison of nicotine addicts and opiate addicts in order to identify that what differences in personality traits and onset age of smoking exist in these two groups that cause some individuals to appeal to ot...

OBJECTIVE To calculate age at onset curves of retinitis pigmentosa (RP) to resolve the difficulty in calculating the recurrence risk in a family. Retinitis pigmentosa is a common hereditary retinal disease that leads to blindness. It is a slow-onset disease, and family members of patients sometimes develop RP later. METHODS We studied 370 patients with typical RP. The age at onset was defined...

one of the most striking features in autosomal dominant polycystic kidney disease (adpkd) is the difference at onset age of end-stage renal disease (esrd). modifier genes may play a role in this phenotypic variability. the mutated nitric oxide synthase 3 gene (nos3), have a modifier effect on the severity of adpkd by impairment of nos3 activity and decreasing of renal vascular nitric oxide prod...