The diagnosis of autism in a female: could it be Rett syndrome?
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The overlap between autism and Rett syndrome clinical features has led to many cases of Rett syndrome being initially diagnosed with infantile autism or as having some autistic features. Both conditions seriously disrupt social and language development and are often accompanied by repetitive, nonpurposeful stereotypic hand movements. The aims of this study were to compare the early and subsequent clinical courses of female subjects with Rett syndrome categorised by whether or not a diagnosis of autism had been proposed before Rett syndrome had been diagnosed and compare the spectrum of methyl-CpG binding protein 2 (MECP2) mutations identified among the two groups. This study made use of a total of 313 cases recorded in two databases: the Australian Rett Syndrome Database (ARSD) and the International Rett Syndrome Phenotype Database (InterRett). Cases with an initial diagnosis of autism had significantly milder Rett syndrome symptoms and were more likely to remain ambulant, to have some functional hand use and not to have developed a scoliosis. Females with the p.R306C or p.T158M mutations in the MECP2 gene were more likely to have an initial diagnosis of autism, and the specific Rett syndrome symptoms were noted at a later age. We recommend that females who are initially considered to have autism be carefully monitored for the evolution of the signs and symptoms of Rett syndrome.
KeywordsMECP2 Rett syndrome Autistic spectrum disorders Autism
The authors would like to acknowledge the National Institute of Child Health and Human Development (USA) for its current funding of the Australian Rett Syndrome Study under NIH grant number 1 R01 HD 43100-01A1. We would also like to acknowledge the International Rett Syndrome Association for its funding of InterRett. DJY is funded by NIH grant R01 HD 43100-01A1, HL and NDK are funded by NHMRC program grant number 003209 and WEK by NIH grant P01 HD 24448. We would like to thank the Australian clinicians who have reported cases and particularly the families for their ongoing support and participation in our study. We would also like to acknowledge the support of the Rett Syndrome Association of Australia, the Australian Paediatric Surveillance Unit and the Rett Syndrome Australian Research Fund. The authors are also grateful for the genotyping of the Australian Rett syndrome cases by Dr. Mark Davis, Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Perth, WA, Australia, and Dr. John Christodoulou, Dr. Linda Weaving and Ms. Sarah Williamson, Western Sydney Genetics Program, the Children’s Hospital at Westmead, Sydney, NSW, Australia.
All data collected for the purposes of the Australian Rett Syndrome Register and the International Rett Syndrome Study Register have been monitored and approved by the Princess Margaret Hospital for Children Human Ethics Committee and performed in accordance with the ethical standards laid down by the Declaration of Helsinki, Fifth Revision, http://www.bmj.com/cgi/content/full/321/7266/913.
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