Distinct Pathogenic Genes Causing Intellectual Disability and Autism Exhibit a Common Neuronal Network Hyperactivity...

Area of Science:

• Neuroscience
• Genetics
• Developmental Biology

Background:

• Pathogenic mutations in EHMT1, MBD5, MLL3, or SMARCB1 cause Kleefstra syndrome spectrum (KSS).
• KSS is a neurodevelopmental disorder characterized by intellectual disability (ID) and autism spectrum disorder (ASD).
• Understanding the molecular basis for the convergence of KSS phenotypes is crucial.

Purpose of the Study:

• To investigate how loss-of-function mutations in KSS genes impact neuronal network development.
• To identify molecular, cellular, and network-level changes in KSS-gene-deficient neurons.
• To elucidate the convergent mechanisms underlying KSS pathophysiology.

Main Methods:

• Utilized a loss-of-function approach in neuronal cultures.
• Assessed molecular, single-cell, and network activity levels.
• Analyzed transcriptional data and gene functions.

Main Results:

• KSS-gene-deficient neuronal networks exhibited hyperactivity and altered network organization.
• An imbalance in the excitatory-inhibitory (E-I) ratio was observed in affected networks.
• Despite distinct transcriptional regulation, KSS target genes converge on neuronal excitability and synaptic function, linked to ID and ASD.

Conclusions:

• KSS genes converge at the level of neuronal network communication.
• This convergence provides insights into the pathophysiology of KSS and related neurodevelopmental disorders.
• Shared functional targets of KSS genes explain the phenotypic overlap in ID and ASD.