Significant changes in the tau A0 and A3 alleles in progressive supranuclear palsy and improved genotyping by silver detection.

BACKGROUND

Progressive supranuclear palsy (PSP) is characterized by intraneuronal inclusions of neurofibrillary tangles formed by aggregated tau protein. A significant association between the tau gene A0/A0 genotype and PSP recently has been reported.

OBJECTIVES

To determine if a significant association between the tau gene A0/A0 genotype and PSP could be found in an independent population with a genetic background different from that in which the initial association was reported, and to standardize a nonradioactive method for tau gene genotyping.

SETTING

Hospital and university research laboratories.

SUBJECTS AND METHODS

To facilitate genotyping of the tau gene, we standardized the conditions for silver-based detection of the tau gene dinucleotide polymorphism. Thirty patients from Spain clinically diagnosed as having probable PSP were included in the study and compared with different control groups.

RESULTS

A highly significant overrepresentation of the A0/A0 genotype (P<.001) and a decrease in the frequency of the A0/A3 genotype were found in the Spanish patients with PSP compared with the control group. A method based on silver detection was standardized for the genotyping of the tau gene.

CONCLUSIONS

The detection of a significant association between the tau gene A0/A0 genotype and PSP in 2 independent populations rules out genetic stratification as an explanation for the association and indicates that the presence of the tau A0/A0 genotype is a risk factor for developing PSP independent of genetic background. Alternatively, the results could be interpreted as a protective effect of the A3 allele.