Peters, S.U., Hundley, R.J., Wilson, A.K., Carvalho, C.M.B., Lupski, J.R., & Ramocki, M.B. (2013). Brief Report: Regression Timing and Associated Features in MECP2 Duplication Syndrome. Journal of Autism and Developmental Disorders, Published online, 2 March 2013.The researchers tested for signs of regression in language and other skills of 17 boys ranging from 3 to 10 years old. They found evidence of language development regression in 8 (47%) of the 17 boys and evidence of other regression in 7 (41%) of 17 boys. Among those who did regress, the average age of regression was 39 months for language skills and 55 months for other skills. The ranges and standard deviations were very large for both types of regression.
This study makes a valuable contribution and does help us understand the phenomenon of regression in boys with MECP2 Duplication syndrome. However, considering the size of the sample the age ranges included, and variability in the results there are some serious limitations on interpreting the results. For example, the average age for regression in other skills (about 55 months) was older than the ages of some of the participants in the study, and the oldest participant was only ten years old. This means that it is likely that some, likely many, and possibly all participants who had not yet shown signs of regression, will do so in the future.
Nevertheless, the study makes it clear that regression affects many of the individuals with MECP2 Duplication Syndrome, that it is highly variable, it may start at an early age, and it sometimes but not always appears along with the advent of seizures.