New insight into Rett syndrome severity
A research collaboration between Australia and Israel has identified a genetic variation that influences the severity of symptoms in Rett syndrome.
The finding is published in the latest edition of the international journal Neurology.
Dr Helen Leonard, who heads the Australian Rett Syndrome Study at The Kids for Child Health Research, said the finding was exciting in that it identifies a potential new target for treatment of the debilitating neurological disorder.
"We know that there is a wide range in the onset and severity of symptoms in patients with Rett syndrome but it has been difficult to give families a firm idea of how the disorder would progress," Dr Leonard said.
"This information is potentially helpful in predicting the clinical progression, but importantly, gives us another area to explore for potential therapies."
In the study, clinical information and DNA samples were gathered from 125 patients from the Australian Rett Syndrome Database and an Israeli cohort coordinated by Dr Bruria Ben Zeev at the Safra Pediatric Hospital, Sheba Medical Centre, Sackler School of Medicine, Tel Aviv. The genetic testing was undertaken by Professor John Christodoulou, from the NSW Centre for Rett Syndrome Research at the Children's Hospital at Westmead in Sydney and Dr Eva Gak from the Sagol Neuroscience Center at the Sheba Medical Centre.
Professor Christodoulou said while it has been established that Rett syndrome is caused by mutations in the MECP2 gene, these new findings have established a correlation between the severity of clinical symptoms and a common brain-derived neurotrophic factor (BDNF) polymorphism.
"Those patients with the normal BDNF genetic variant had less severe symptoms, with later onset and frequency of seizures," Dr Christodoulou said.
"We know that BDNF plays a major role in the development, survival and function of brain cells. What we now have to establish is the nature of the interaction between MECP2 and BDNF."
"It may be that if we can stimulate BDNF within patients with Rett syndrome, there is a chance that we can delay the onset of seizures and reduce some of the more debilitating aspects of the disorder."
The research was supported by funding from the National Institutes of Health (USA), the National Health and Medical Research Council (Australia), the International Rett Syndrome Foundation and the Rett Syndrome Australian Research Fund.
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About Rett Syndrome
Rett syndrome is a relatively rare neurological disorder that usually affects girls. The clinical diagnosis has often been uncertain in early childhood as the symptoms may be confused with those occurring in other disorders such as autism, cerebral palsy and developmental delay. Rett syndrome affects around one in every 8,500 female births. Mutations in the MECP2 gene on the X chromosome have been identified as a cause of Rett syndrome. There is no known cure.