Research published in December 2016 provides a bit more information about seizure disorders in MECP2 duplication syndrome, particularly as they compare to seizure disorders in Rett syndrome. In general, this is a great piece of research as it describes the course of seizure disorders in Rett syndrome over a period of years. It emerged from the earlier natural history study. Unfortunately from the the perspective of MECP2 duplication syndrome, this publication is a bit disappointing, not because of any weakness in the sturdy or the reporting, but merely because the number of participants with MECP2 duplication and the number of observations in the study was relatively small, which only permitted a very limited picture of this group. If there is a lesson for the MECP2 duplication syndrome study to be learned from this study, it may be the importance of participation in the current natural history study in order for researchers to be able to glean useful information.
Nevertheless this study did briefly report some general observations relevant to MECP2 duplication syndrome:
Males with MECP2 duplication, a small group of particular clinical interest, had higher point prevalence of seizures than any Rett syndrome group. However, the age of seizure onset was generally later in MECP2 duplication than in Rett syndrome, and the cumulative prevalence was only 70%.
This is consistent with an earlier parent survey conducted through this blog shat showed great variability in the age of onset of seizures in MECP2 duplication with some individuals having onset in adolescence or adulthood, but approaching 100% having some seizures be age 25.
Another issue of interest addressed in this publication though not specifically in regard to MECP2 duplication syndrome is regrading seizure like neurologically driven behaviour that may not be accompanied by the seizure like brainwave activity. It is clear that individuals with MECP2 duplication typically have a wide variety of unusual motor activity including a wide variety of atonic, tonic, myoclonic, and other seizure types, and it is clear that most have or develop abnormal brain wave patterns. Anecdotal reports, however, suggest that some electrographic brainwave patterns that appear to be characteristic of seizures produce no observable motor responses, and some apparent motor spasms or loss of tone are not accompanied by corresponding EEG changes. This raises numerous questions that need to be explored. If some of the seizure-like motor behaviours are not seizures, what are they? Can they be treated and should they? These and many more questions need to be answered.
Tarquinio, Hou,Berg et al.(2016). Longitudinal course of epilepsy in Rett
syndrome and related disorders, Brain, doi:10.1093/brain/aww302