Article Title
Young, DJ, Bebbington, A, Anderson, A, Ravine, D, Ellaway, C, Kulkarni, A, de Klerk, N, Kaufmann, WE & Leonard, H 2008. The diagnosis of autism in a female: could it be Rett syndrome. Download snapshot, see journal abstract.
Background
Many girls with Rett syndrome initially show autistic-like symptoms and therefore, may be diagnosed with infantile autism. Autism is one of the most common misdiagnoses in Rett syndrome.
What did we do
We wanted to compare the symptoms and genetic characteristics of girls with Rett syndrome who were initially diagnosed with autism compared to those who had not previously been diagnosed with autism.
This study used information provided by families to the Australian Rett Syndrome study and to the International Rett Syndrome Database (InterRett). Data from 313 families with a child with Rett syndrome ranging from 1.5 to 45 years of age who had been found to have a mutation in the MECP2 gene were included in this study.
What we found
Of these, 55 families (17.6%) had reported an initial diagnosis of autism for their daughter. One of the eight common mutations (or mutation grouping) in the MECP2 gene (p.T158M, p.R168X, p.R294X, p.R270X, C-terminal deletions, R133C, R306C, R255X) was present in 212 girls (~70%), with the remaining girls having other types of mutations.
We found that girls with a p.R306C or a p.T138M mutation were more likely to be initially diagnosed with autism as were girls who developed the characteristics of Rett syndrome later. These girls also tended to have milder symptoms overall when compared to girls that did not receive a diagnosis of autism.
What does it mean
Although the features of Rett syndrome are quite different to that of autism, it is still likely that some girls with Rett syndrome may be misdiagnosed as autism. This could be a problem because the true diagnosis is important for ongoing management and support. It is still unclear if the milder presentation of the group of girls diagnosed with autism was due to their mutation type or to behavioural intervention programs that they may have received. We recommend that girls who are diagnosed with autism be closely monitored for features of Rett syndrome that may later develop.