Gene specific effects on brain volume and cognition of in frontotemporal lobar degeneration.

BACKGROUND AND OBJECTIVES

has been proposed as a modifier of disease risk in FTLD-TDP, particularly in mutation carriers. Furthermore, has been investigated as a disease modifier in the context of healthy aging and across multiple neurodegenerative diseases. The objective of this study is to evaluate and compare the effect of on gray matter volume and cognition in each of the common genetic FTD groups and in sporadic FTD patients.

METHODS

Participants were enrolled through the ARTFL/LEFFTDS Longitudinal Frontotemporal Lobar Degeneration (ALLFTD) study, which includes symptomatic and presymptomatic individuals with a pathogenic mutation in , symptomatic non-mutation carriers, and non-carrier family controls. All participants were genotyped for the rs1990622 SNP. Cross-sectionally, linear mixed-effects models were fitted to assess an association between and genetic group interaction with each outcome measure (gray matter volume and UDS3-EF for cognition), adjusting for education, age, sex and CDR+NACC-FTLD sum of boxes. Subsequently, associations between and each outcome measure were investigated within the genetic group. For longitudinal modeling, linear mixed-effects models with time by predictor interactions were fitted.

RESULTS

The minor allele of rs1990622, linked to a decreased risk of FTD, associated with greater gray matter volume in mutation carriers under the recessive dosage model. This was most pronounced in the thalamus in the left hemisphere, with a retained association when considering presymptomatic mutation carriers only. The minor allele of rs1990622 also associated with greater cognitive scores among all mutation carriers and in presymptomatic mutation carriers, under the recessive dosage model.

DISCUSSION

We identified associations of with gray matter volume and cognition in the presence of and mutations. This further supports as modifier of TDP-43 pathology. The association of with outcomes of interest in presymptomatic and mutation carriers could additionally reflect TMEM106B's impact on divergent pathophysiological changes before the appearance of clinical symptoms.