RELN and early-onset autosomal dominant Alzheimer disease: A possible interaction between reelin and Aβ was first shown by adding synthetic Aβ42 to cultured SH-SY5Y neuroblastoma cells, causing a dose-dependent increase of the 180-kDa reelin fragment without changing reelin messenger RNA levels.49 Further studies on Alzheimer’s disease-subjects revealed that reelin extracted from cortex tends to be of higher molecular mass than the active, signalling-competent form,50 and that oligomeric Aβ and reelin co-immunoprecipitate.51