Genetic Risk Factors of Creutzfeldt-Jakob Disease in the Population of Newborns in Slovakia

The most frequent human prion disease is Creutzfeldt–Jakob disease (CJD). It occurs as sporadic (sCJD), genetic (gCJD), iatrogenic (iCJD) form and as variant CJD. The genetic form represents about 10–15% of confirmed cases worldwide, in Slovakia as much as 65–75%. Focal accumulation of gCJD was confirmed in Orava region. The most common point mutation of the prion protein gene (PRNP) is E200K. CJD has a long asymptomatic phase and it is not known when the carriers of the mutation E200K become infectious. Precautions to prevent iCJD are focused especially on clinical CJD cases, but asymptomatic CJD-specific mutation carriers cannot be excluded, and represent a potential genetic CJD-risk group. The aim of this study was to determine the occurrence, frequency and geographic distribution of the E200K mutation among the newborns, comparing the areas of focal accumulation of gCJD with extra-focal ones, as well as distribution of the polymorphism M129V of the PRNP gene. A total of 2915 samples of dry blood spots from anonymous newborns were analyzed. We used RealTime PCR method to determine the presence of the E200K mutation and the M129V polymorphism. Genetic testing revealed 13 carriers of the E200K mutation. Investigation of the M129V polymorphism affirmed higher representation of methionine homozygotes (48% MM, 44% MV, 8% VV). Achieved results fully confirmed our previous observations concerning both the specific and nonspecific genetic CJD risk among the Slovak general population. The 48% of methionine homozygotes and 4 carriers of the E200K mutation among 1000 live-born children in Slovakia underline the benefits of genetic testing.