PIDD1 and intellectual disability, autosomal recessive: Intriguingly, another study on autosomal recessive intellectual disability identified a loss-of-function mutation in the PIDD1 death domain in two unrelated Pakistani families [95], and additional novel mutations in PIDD1 were identified and are currently characterized (John Vincent, personal communication, 2020), supporting the idea that PIDDosome formation is required for brain development or proper function.