Association between the prion protein gene polymorphisms and incidence of fatal familial insomnia: a casecontrol study in a Chinese population

This study aimed to explore the association between the prion protein gene (PRNP) polymorphisms and incidence of fatal familial insomnia (FFI) in a Chinese population. Twenty FFI patients were chosen as the case group and forty healthy individuals as the control group. PRNP gene polymorphism sites were screened out, and M129V and E219K were identified as the polymorphic sites. Peripheral blood was extracted from all subjects for PRNP detection and genotyping using polymerase chain reaction restriction fragment length polymorphism. Epidemiological case investigation was conducted in the FFI patients to collect related information. Multivariate logistic regression analysis was employed to screen independent risk factors of FFI and SHEsis online software was used to analyze the haplotypes of M129V and E219K sites of PRNP. Family history, body weight and sleep duration were significantly different in the case group. The M/M, M/V genotypes and M allele at the M129V of PRNP gene could increase the risks of FFI, indicating that carrying 129M/M and 129M/V genotypes were more likely to suffer from FFI than those with 129V/V genotype. The M/M genotype in M129V was significantly correlated with the natural history, disease progression, neurological and pathological changes, loss of weight, electroencephalogram abnormality and sleep time. Multivariate logistic regression analysis indicated that the M/M, M/V genotypes at M129V of PRNP gene, FFI family history, body weight loss and sleep duration < 3 h were all risk factors of FFI. Additionally, VE haplotype might be a potential protective haplotype for FFI (OR = 0.293, 95% CI = 0.093 similar to 0.919). These results collectively indicated that the PRNP M129V polymorphisms may be associated with the incidence of FFI.