The autism spectrum phenotype in ADNP syndrome

Area of Science:

• Neurogenetics
• Developmental Neuroscience
• Autism Spectrum Disorders Research

Background:

• Pathogenic disruptions to the activity-dependent neuroprotector homeobox (ADNP) gene are common genetic mutations linked to autism spectrum disorders (ASDs).
• Individuals with ADNP disruptions exhibit a range of features including ASD, intellectual disability (ID), dysmorphic features, and hypotonia.
• The specific ASD phenotype in ADNP disruptions may differ from other genetic causes of ASD.

Purpose of the Study:

• To examine the distinct autism spectrum disorder (ASD) phenotype in youth with ADNP gene disruptions.
• To compare the ASD characteristics of individuals with ADNP mutations to those with CHD8 mutations, other ASD-associated gene mutations, and idiopathic ASD.
• To investigate the relationship between verbal intelligence and social impairment in individuals with ADNP disruptions.

Main Methods:

• A cohort of 116 youth (ages 4-22) with ASD was analyzed.
• Participants included a group with ADNP mutations (n=11), CHD8 mutations (n=11), other gene mutations (n=53), and idiopathic ASD (n=41).
• ASD phenotypes, including social affect symptoms, intellectual disability, and restricted/repetitive behaviors, were compared across groups.

Main Results:

• Individuals with ADNP disruptions showed higher rates of intellectual disability (ID) but less severe social affect symptoms compared to CHD8 and idiopathic ASD groups.
• Verbal intelligence explained more variance in social impairment in the ADNP group than in comparison groups.
• Restricted and repetitive behaviors in the ADNP group were characterized by high levels of stereotyped motor behaviors, contrasting with restricted interests in the idiopathic ASD group.

Conclusions:

• The ADNP gene plays a significant role in cognitive functioning, particularly learning and memory.
• Social impairments in ADNP syndrome are closely related to the severity of verbal deficits.
• These findings highlight the importance of understanding gene-specific phenotypes within the broader spectrum of autism.