# Shared Disease Mechanisms in Neurodevelopmental Disorders: A Cellular and Molecular Biology Perspective

## TL;DR

This paper explores shared disease mechanisms in neurodevelopmental disorders like epilepsy and autism to better understand how genetic changes affect brain development and inform future treatments.

## Contribution

The paper identifies common genetic and molecular mechanisms across neurodevelopmental disorders, focusing on genes like CDKL5, TSC1/2, SCN1a, and TANC2.

## Key findings

- Genes such as CDKL5, TSC1/2, SCN1a, and TANC2 are linked to epilepsy, ASD, and other NDDs through various cellular and molecular pathways.
- Different pathogenic variants in the same gene can lead to distinct phenotypic outcomes in neurodevelopmental disorders.
- Understanding genotype–phenotype relationships may help develop targeted treatments for these disorders.

## Abstract

Neurodevelopmental disorders (NDDs) are defined as a group of conditions that result from impaired brain development. Disorders that are commonly classified under NDDs include intellectual disability (ID), autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), communication and learning disorders, developmental delay (DD), brain malformations, cerebral palsy, Down syndrome, schizophrenia, and childhood epilepsies. A significant hinderance in the development of targeted treatments for NDDs are gaps in understanding how underlying genetic changes alter cellular physiology and how these changes may converge or diverge across NDDs with similar symptoms. Here, we focus on the genetic overlap between epilepsy, ASD, and other NDDs to identify common cellular and molecular mechanisms that may inform future treatments for each of these disorders individually or together. We describe several genes—including CDKL5, TSC1/2, SCN1a, and TANC2—that have been associated with epilepsy, ASD, or other NDD phenotypes that play a critical role in regulating one or more stages of brain development or function but differ widely in their disease-causing mechanisms. We also describe genotype–phenotype relationships. Finally, how a gene may cause NDDs through distinct functional pathways, or where different types of pathogenic variants within the same gene can have significantly different phenotypic outcomes is detailed.