Objectives: The aim of the present study was to determine if individuals with maternal interstitial 15q duplications class I and II have phenotypic differences in language and neuropsychological evaluations.
Methods: ADOS/ADI-R were used for autism diagnosis. Peabody Picture vocabulary test four edition (PPVT-4) was done to evaluate receptive vocabulary. The neuropsychological tests done, were IQ and Vineland-II.
Results: Nine patients were recruited through the IDEAS parent support group (www.idic15.org): 4 class I and 3 class II were available for the analysis. All subjects scored as ASD upon ADOS/ADI-R analysis. In the neuropsychological evaluations 2/5 subjects had a low average IQ score, 3/5 were borderline. Most of the subjects had a low-moderate adaptive functioning score on the Vineland II evaluation with no differences among groups. All subjects performed below age corrected average for receptive vocabulary (PPVT-IV) but we found a significant difference (pval<0.03) between class I and class II subjects.
Conclusions: Language trends will require more subjects to be accurately described. Interestingly there are no major phenotypic differences in maternal deletion subjects (Angelman syndrome), except for the lack of verbal language in Class I patients, so it will be important to determine the roll in language of those four extra genes duplicated/deleted in Class I patients.