THE RISK OF DEVELOPING CREUTZFELDT-JAKOB-DISEASE IN SUBJECTS WITH THEPRNP GENE CODON-200 POINT MUTATION

We determined the penetrance of the PRNP 200(Lys) mutation in the larg e cluster of Creutzfeldt-Jakob disease (CJD) cases among Jews of Libya n-Tunisian origin living in Israel, utilizing data from 52 carriers wi th definite or probable CJD and 34 unaffected mutation carriers. A lif e table analysis was carried out with development of CJD as the end po int. The probability of developing CJD rose with age, fitting a second -order regression curve (R = 0.97, p < 0.001). The cumulative penetran ce reached 50% at the age of 60 and 80% at 80 years. Including seven e lderly possible CJD patients in the analysis made the penetrance appro ach 100% by age eighty. The penetrance of the mutation is high, and al though age is a predominant influencing factor, other factors, such as gender, may also play a role.