When APP mice are crossed with the leptin-deficient ob/ob model they showed no change in Aβ burden, however both amyloid angiopathy and angiitis were increased together with exacerbated cognitive dysfunction [66], while in contrast when Tg2576 mice are crossed with Irs2-/- insulin resistant mice show reduced Aβ pathology and cognitive improvement [24]. The gene discussed is IRS2; the disease is vasculitis.