Complete penetrance of Creutzfeldt-Jakob disease in Libyan Jews carrying the E200K mutation in the prion protein gene.
BACKGROUND
Creutzfeldt-Jakob disease (CJD) is a prion disease which is manifest as a sporadic, inherited, and transmissible neurodegenerative disorder. The mean age at onset of CJD is approximately 60 years, and as such, many people destined to succumb undoubtedly die of other illnesses first. The delayed onset of CJD has complicated the analysis of inherited forms of the illness and led to the suggestion that mutations in the prion protein (PrP) gene are necessary but not sufficient for prion disease despite genetic linkage; indeed, an environmental factor such as a ubiquitous virus has been proposed as a second necessary factor.


METHODS
To examine what appeared to be incomplete penetrance, we applied a life-table analysis to clinical and pedigree data from a cluster population of Libyan Jews in which the E200K mutation is prevalent. The study population included 42 affected and 44 unaffected members of 13 Libyan Jewish families, all of whom possessed the E200K mutation.


RESULTS
The calculated value using life table analysis is 0.77 at age 70 which increases to 0.89 if a mutation carrier survives to age 80 and 0.96 if age 80 is surpassed.


CONCLUSIONS
These data argue that the E200K mutation alone is sufficient to cause prion disease and does so in an age-dependent manner.
Spudich
S
S
Department of Neurology, University of Calfornia, San Francisco 94143-0518, USA.
Mastrianni
J A
JA
Wrensch
M
M
Gabizon
R
R
Meiner
Z
Z
Kahana
I
I
Rosenmann
H
H
Kahana
E
E
Prusiner
S B
SB
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D007562:Creutzfeldt-Jakob Syndrome / Q000453:epidemiology* / Q000235:genetics* / Q000401:mortality; D006580:Genetic Carrier Screening; D008040:Genetic Linkage; D006801:Humans; D007585:Jews / Q000235:genetics*; D008002:Libya / Q000208:ethnology; D015993:Life Tables; D008875:Middle Aged; D017354:Point Mutation; D011328:Prions / Q000235:genetics*; D011336:Probability
D011328:Prions