Background:

Adults with Down syndrome (DS) are at very high risk for Alzheimer’s disease (AD). Neurofilament light (NF-L) has emerged as a potential blood-based biomarker of neurodegeneration due to AD.

Objective:

To understand the relationship between plasma NF-L with age, brain amyloid, and tau pathology, neurodegeneration as well as cognitive and functional performance.

Methods:

We analyzed imaging data as well as cognitive measures in relation to plasma NF-L in adults with DS, ages 30 to 60 who were enrolled in the Down Syndrome Biomarker Initiative.

Results:

We found significant correlations between NF-L plasma concentrations and amyloid pathology (r = 0.73, p = 0.007, p_a = 0.041) and significant inverse correlations with regional glucose metabolism in 5 of 6 regions examined, which were Anterior cingulate (r = –0.55, p = 0.067, p_a = 0.067), Posterior cingulate r = –0.90, p < 0.001, p_a < 0.001), Lateral Temporal (r = –0.78, p = 0.004, p_a = 0.012), Frontal cortex (r = –0.90, p < 0.001, p p_a < 0.001), Parietal cortex (r = –0.82, p = 0.002, p_a = 0.008), Precuneus (r = –0.73, pa = 0.010, p_a = 0.020), and with hippocampal volume (r = –0.52, p = 0.084, p_a = 0.084); and an inverse correlation with direct measures of cognition: CAMCOG (r = –0.66 p = 0.022, p_a = 0.066) and positive correlation with CANTAB Paired Associates Learning (PAL) error rate (r = 0.68, p = 0.015, p_a = 0.060). Finally, we found inverse relationships with informant-based functional measures (r = –0.57, p = 0.059, p_a = 0.084) and OMQ-PF (r = –0.74, p = 0.008, p_a = 0.041).

Conclusion:

Plasma NF-L is associated with progressive neurodegeneration as well as with declines in cognitive and functional measures in adults with DS.