Mechanism of KMT5B haploinsufficiency in neurodevelopment in humans and mice.

Pathogenic variants in KMT5B, a lysine methyltransferase, are associated with global developmental delay, macrocephaly, autism, and congenital anomalies (OMIM# 617788). Given the relatively recent discovery of this disorder, it has not been fully characterized. Deep phenotyping of the largest (n = 43) patient cohort to date identified that hypotonia and congenital heart defects are prominent features that were previously not associated with this syndrome. Both missense variants and putative loss-of-function variants resulted in slow growth in patient-derived cell lines. KMT5B homozygous knockout mice were smaller in size than their wild-type littermates but did not have significantly smaller brains, suggesting relative macrocephaly, also noted as a prominent clinical feature. RNA sequencing of patient lymphoblasts and Kmt5b haploinsufficient mouse brains identified differentially expressed pathways associated with nervous system development and function including axon guidance signaling. Overall, we identified additional pathogenic variants and clinical features in KMT5B-related neurodevelopmental disorder and provide insights into the molecular mechanisms of the disorder using multiple model systems

Preschool children's persuasion knowledge: The contribution of theory of mind

Two studies investigate the influence of developmental variables on the emergence of persuasion knowledge in children ages three to five years. Theory of mind (a form of social development) consistently explains a significant amount of variance in children's persuasion knowledge. Theory of mind is a well-researched variable in the developmental psychology literature. This form of social development enables a child to understand the mental states of others and to use that mental state understanding to predict others' future behavior. The results of the current study indicate that before theory-of-mind development, children are unable to recognize persuasion in advertising, most likely because they cannot think about the intentions of the advertiser. The findings are important to the development of child consumer literacy and contribute to the extant literature by demonstrating that developmental factors can explain how persuasion knowledge develops. The authors discuss theoretical, practical, and public policy implications