APP and Alzheimer disease: The AD genotype had no effect on circulating leptin (APP+/+ × PS1+/+ 81 ± 12 ng/mL, n = 12 F/26 M vs. APPΔNL/ΔNL× PS1P264L/P264L 99 ± 12 ng/mL, n = 15 F/23 M; p = 0.3).