MECP2 duplication syndrome: A rare X-linked neurodevelopmental disorder primarily affecting boys
MECP2 duplication syndrome (MDS) is a rare, X-linked neurodevelopmental disorder caused by the duplication of the MECP2 gene. Unlike Rett syndrome, MDS most often affects boys. Children and adults with MDS commonly experience severe intellectual disability, developmental delay, seizures, recurrent infections, and difficulties with movement and communication.
Despite its discovery nearly two decades ago, much remains unknown about how the disorder progresses over time. Our research team is working to change that.
The International MECP2 Duplication Database (MDBase)
To better understand the natural history of MDS, we established the International MECP2 Duplication Database (MDBase) in 2020. This global registry collects information directly from families and caregivers about the health, development, and wellbeing of individuals with MDS.
Through MDBase, families worldwide are helping to:
- Identify common medical comorbidities and developmental patterns
- Understand how MDS changes with age
- Support the design of future clinical trials and therapies
Our research is conducted entirely online—families can participate from anywhere in the world. If you would like to register or learn more, please visit the registration page.
Our Publications
Our work on MDS and the MDBase has resulted in several key papers advancing knowledge of MDS:
- Giudice-Nairn et al. (2019) – The incidence, prevalence and clinical features of MECP2 duplication syndrome in Australian children
Provided the first population-based estimates of how common MDS is in Australian children, detailing early clinical signs to support earlier diagnosis.
Read here - Ta et al. (2022) – A brief history of MECP2 duplication syndrome: 20 years of clinical understanding
Summarised two decades of international research, highlighting the evolution of knowledge about symptoms, mechanisms, and management.
Read here - Ta et al. (2022) – Medical comorbidities in MECP2 duplication syndrome: Results from the International MECP2 Duplication Database
Provided the first large-scale, data-driven characterisation of the medical profile of MECP2 duplication syndrome, revealing that recurrent respiratory infections and epilepsy are among the most prevalent and life-limiting complications in affected individuals.
Read here - Ta et al. (2022) – Development of an International Database for a Rare Genetic Disorder: The MECP2 Duplication Database (MDBase)
Described how MDBase was created with global family and clinician input, outlining its structure, data collection methods, and international reach.
Read here - Cherian et al. (2023) – Quality of life and wellbeing in families of children with MECP2 duplication syndrome
Explored caregiver wellbeing and family coping strategies, providing the first insights into psychosocial impacts of caring for a person with MDS.
Read here - Ta et al., (in press, 2025) – Functional skills in MECP2 duplication syndrome: Developmental dynamics and regression
(Accepted for publication in the Orphanet Journal of Rare Diseases – not yet publicly available)
This study of 160 individuals provides the first comprehensive mapping of how gross motor, fine motor, and communication skills develop and regress in MDS. It highlights gender differences, associations with seizure activity, and the impact of duplication size on walking and communication outcomes.
(Full text will be linked once published.)