Isolated duplications of PAFAH1B1 have been associated with mild developmental delay and hypotonia, while isolated duplications of YWHAE have been associated with autism.
PAFAH1B1/LIS1 and YWHAE, which were deleted in isolated lissencephaly (PAFAH1B1/LIS1 alone) and Miller-Dieker syndrome (both genes), were found to be duplicated in patients with developmental delay.
While deletion of chromosome 17p13.3 (encompassing PAFAH1B1 and YWHAE genes) is known to result in Miller-Dieker syndrome (OMIM 247200), 17p13.3 microduplication gives rise to a condition commonly associated with developmental delay and autism spectrum disorder.