In addition, neuronal deficiency of presenilin 1, whose mutations trigger the dominant form of the disease [51], causes accumulation of autophagosomes and MVBs [52, 53], while conditional knockout mice for presenilin 1 accumulate autophagosomes in the brain [54], indicating a link between abnormal processing of presenilin substrates and abnormalities in those pathways. Here, PSEN1 is linked to hyperinsulinemic hypoglycemia, familial, 4.