Neurological conditions account for over 6% of the global disease burden. There are more than 600 neurological disorders, and cognitive dysfunction, also referred to as intellectual disability (ID), occupies a prominent position in this list. Cognitive dysfunction arises from the failure of neuronal cells to organize into a complex network and remodel this network in response to learning and experience. It is manifested by deficits in adaptive behaviors in everyday social and practical skills. Due to its high prevalence and the lifetime cost of care per individual, in the range of $1-2 million in United Sates (CDC), it presents a significant health burden. Genetic and functional studies of the genes and protein determinants of ID have helped to elucidate the molecular pathways of human brain development in health and disease. However, the identity of a large number of essential molecular and cellular components still remain elusive. The objectives of our study are to expand the genetic repertoire of causal ID genes and characterize their role in neuronal structure and cognitive function. The rationale is that identification and functional elucidation of causative gene variants that lead to cognitive dysfunction will be essential for understanding brain function and for developing improved diagnostic tools and efficacious preventive and therapeutic agents for neurological disorders, including ID. There are 3 aims of our comprehensive research program: 1) Ascertain and clinically phenotype members of extended families segregating autosomal recessive intellectual disability (ARID); 2) identify new ARID genes and gene products; and 3) determine the functions of prioritized novel ARID genes using multifaceted approaches, including analysis of spatiotemporal expression patterns in mouse brain, targeting in cultured rat hippocampal neurons, effects on cell morphology and synapse abundance, synaptic transmission and plasticity in neuronal cells by electrophysiology and live-cell imaging assays. The project will advantageously combine human clinical assessment, genetic and functional analyses relevant to brain development and function. Impact: Execution of the proposed studies will generate new knowledge that is clinically relevant, with high potential to impact ID molecular diagnosis, prognoses, and identify novel therapeutic targets to slow progression, delay onset, and possibly devising precision medicine approaches for ID.

Genetics and Functional Studies of Autosomal Recessive Neurological Disorders