SLC16A7 and early-onset autosomal dominant Alzheimer disease: For instance, one of the earliest symptoms in preclinical Alzheimer’s disease (AD) is excessive daytime sleepiness and difficulty in maintaining long periods of consolidated wakefulness55,56 resembling the fragmented waking pattern we identified in our transgenic mice lines after deleting astrocytic MCT4 and orexinergic MCT2 in the LH.