How does 15q11–13 duplication change gene expression in autism?

PostedNovember 19, 2025

UpdatedNovember 19, 2025

ByMy Patient Advice

Author: Lucia Alvarez, MSc | Reviewed by: Dr. Rebecca Fernandez, MBBS

The 15q11–13 duplication is one of the most frequently identified genetic changes linked to autism, and it has a profound effect on gene expression in the developing brain. This specific duplication occurs on chromosome 15 and involves an extra copy of a region containing several genes that regulate neural function, especially those related to GABA signalling, a system crucial for balancing brain activity.

When this region is duplicated, the additional gene copies can lead to an overexpression of key proteins, particularly those involved in inhibitory neurotransmission. This can disrupt the delicate balance of excitation and inhibition in the brain, contributing to traits such as sensory sensitivities, social challenges and repetitive behaviours commonly seen in autism. The 15q11–13 duplication is also associated with a subtype of autism that often includes developmental delay, seizures and intellectual disability, making it a significant area of study in both research and clinical genetics.

The Effects of 15q11–13 Duplication on Brain Function

Here are two key ways this duplication alters gene expression in autism:

Increases dosage of GABA-related genes

This region includes genes like GABRB3, which affect how neurons calm down after firing. Too much of this activity can interfere with brain circuit development and may reduce flexibility in learning and behaviour.

Disrupts genetic balance and regulatory control

Having extra copies of genes can overwhelm normal regulatory systems, leading to widespread changes in how genes are expressed across the brain. These effects contribute to the neurological differences seen in some autistic individuals.

Understanding the impact of 15q11–13 duplication on gene expression is vital for recognising distinct autism subtypes and guiding targeted support. Visit providers like Autism Detect for personal consultations and further guidance on screening and support.

For a deeper dive into the science, diagnosis and full treatment landscape, read our complete guide to Genetic Influences.

Lucia Alvarez, MSc

Author

Lucia Alvarez is a clinical psychologist with a Master’s in Clinical Psychology and extensive experience providing evidence-based therapy and psychological assessment to children, adolescents, and adults. Skilled in CBT, DBT, and other therapeutic interventions, she has worked in hospital, community, and residential care settings. Her expertise includes grief counseling, anxiety management, and resilience-building, with a strong focus on creating safe, supportive environments to improve mental well-being.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the author's privacy.

Dr. Rebecca Fernandez, MBBS

Reviewer

Dr. Rebecca Fernandez is a UK-trained physician with an MBBS and experience in general surgery, cardiology, internal medicine, gynecology, intensive care, and emergency medicine. She has managed critically ill patients, stabilised acute trauma cases, and provided comprehensive inpatient and outpatient care. In psychiatry, Dr. Fernandez has worked with psychotic, mood, anxiety, and substance use disorders, applying evidence-based approaches such as CBT, ACT, and mindfulness-based therapies. Her skills span patient assessment, treatment planning, and the integration of digital health solutions to support mental well-being.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the reviewer's privacy.