Early Communicative Functions and Later Autism

This study is a de-identified retrospective review of previously collected clinical data. The aim of the study is to compare acquisition of early communication skills between individuals with fragile X syndrome (FXS) with and without a later diagnosis of autism spectrum disorder (ASD). Retrospective data from 150 participants in the KKI’s Fragile X Clinic will be utilized. Research questions that this study will try to answer are following:

1) What is the distribution (mean and range) of age of onset first words?
2) Have the participants, and if so how many, exhibited a developmental platou of either verbal (speech and language) or non-verbal communication skills?
3) Is there a difference between groups (i.e., FXS with ASD and FXS without ASD) in terms of presence of a developmental plateau in the communication skills?
4) Is there a relationship between ASD status and its severity (PDD NOS vs. autism) and reports of delayed verbal skills (i.e., speech, language)?
5) Does the age of acquisition of first words predict ASD status and its severity (PDD NOS vs. autism) using a logistic regression model?
6) Does “a developmental plateau” moderate the relationship between age of onset of using first words and presence or absence of ASD?

Our hypothesis is that a late onset of using first words will lead to a diagnosis of ASD if the participant experienced a developmental plateau.