Autism and Neurodegeneration: Distinct Disorders or a Shared Biological Continuum?

Area of Science:

• Neuroscience
• Genetics
• Epidemiology

Background:

• Autism spectrum disorder (ASD) is a neurodevelopmental condition, while neurodegenerative diseases involve progressive neuronal decline.
• Traditional separation of these conditions may overlook shared biological mechanisms.
• Emerging evidence suggests potential overlap in underlying biology across the lifespan.

Purpose of the Study:

• To evaluate if ASD and neurodegenerative disorders are distinct entities or linked by shared mechanisms.
• To synthesize evidence across genetic, molecular, cellular, circuit, and epidemiological studies.
• To examine these links within a lifespan-oriented framework.

Main Methods:

• Narrative review of existing literature.
• Synthesis of genetic, molecular, cellular, and circuit-level studies in ASD and neurodegenerative diseases (Alzheimer's, Parkinson's, ALS).
• Analysis of epidemiological data on co-occurrence and risk.

Main Results:

• ASD and neurodegenerative diseases share overlapping mechanisms: mitochondrial dysfunction, impaired proteostasis, neuroimmune alterations, and network instability.
• Genetic and molecular pathways influence both early neurodevelopment and later neuronal resilience.
• Epidemiological data show increased dementia/parkinsonian risk in autistic adults, suggesting latent vulnerabilities.

Conclusions:

• ASD and neurodegenerative diseases are distinct but share biological substrates.
• Lifespan convergence model: early alterations may create vulnerabilities intersecting with later neurodegeneration.
• Integrated research and clinical approaches are needed, viewing brain health as a continuous lifespan process.