Abstract Duplications of chromosome 15 may be one of the most common single genetic causes of autism spectrum disorders (ASD), aside from fragile X. Most of the cases are associated with maternally derived interstitial duplication involving 15q11-13. This case report describes a female proband with a maternally derived interstitial duplication of proximal 15q. She did not exhibit any symptoms of ASD apart from some developmental delay. By adolescence, she showed mild dysmorphism, a discrepant profile on the Wechsler Intelligence Scale for Children (Verbal IQ = 87; Per- formance IQ = 65) and a major deficit in visual-spatial abilities affecting fine motor skills, mathematical rea- soning, visual memory and some global reading tasks. This is one of the first reports of a child with a maternal duplication who exhibits a visual-spatial deficit without ASD. Keywords Chromosome 15 Æ Prader-Willi/Angelman Syndrome critical region Æ Maternally derived interstitial duplication Æ Pervasive developmental disorder Æ Visual-spatial deficit Introduction According to several authors (e.g. Cook, 2001; Schroer et al., 1998), duplications of chromosome 15 may be one of the most common single genetic causes of aut- ism, aside from Fragile X. It is also the most frequent non-X-linked cause reported in the literature (Lauris- ten, Mors, Mortensen, & Ewarld, 1999). However, in most genetic abnormalities linked to autism, the autism phenotype or syndrome is not always present and is most likely a secondary phenomenon (Cohen et al., 2005). Duplications of chromosome 15 involved in autistic syndrome are located in the Angelman-Prader- Willi region (15q11-q13). Duplications may result from partial trisomy 15 (presenting an extra marker chro- mosome visible with conventional cytogenetics, which must be confirmed as 15q11-q13 derivative by Fluo- rescent in situ hybridization, or FISH), or from D. Cohen (&) Æ C. Martel Æ N. De ´ chambre Æ C. Amy Æ L. Duverger De ´ partement de Psychiatrie de l’Enfant et de l’Adolescent, Universite ´ Pierre et Marie Curie, Groupe Hospitalier Pitie ´- Salpe ´ trie `re, AP-HP, 47 bd de l’Ho ˆ pital, 75013 Paris, France e-mail: david.cohen@psl.aphp.fr M. Plaza Æ D. Cohen Æ J.-M. Guile CNRS, ‘‘Cognition et comportement’’, Universite ´ Paris V, Boulogne, France A. Wilson Æ L. Cohen INSERM-CEA Unit 562 ‘‘Cognitive Neuroimaging’’, Service Hospitalier Fre ´de ´ ric Joliot, CEA-DRM-DSV, Orsay, France J.-M. Guile De ´ partement de Psychiatrie, Universite ´ de Montre ´ al, Montre ´ al, Canada E. Pipiras Æ B. Benzacken Service de Cytoge ´ne ´ tique, Groupe Hospitalier Jean Verdier, Bondy, France H. Cave ´ Service de Biochimie ge ´ne ´ tique, Groupe Hospitalier Robert Debre ´ , Paris, France D. He ´ ron Fe ´de ´ration de Ge ´ne ´ tique, Groupe Hospitalier Pitie ´- Salpe ´ trie ` re, Paris, France J Autism Dev Disord DOI 10.1007/s10803-006-0228-5 123 BRIEF REPORT Brief Report: Visual-Spatial Deficit in a 16-year-old Girl with Maternally Derived Duplication of Proximal 15q David Cohen Æ Claire Martel Æ Anna Wilson Æ Nicole De ´ chambre Æ Ce ´line Amy Æ Ludovic Duverger Æ Jean-Marc Guile Æ Eva Pipiras Æ Brigitte Benzacken Æ He ´le `ne Cave ´ Æ Laurent Cohen Æ Delphine He ´ron Æ Monique Plaza Ó Springer Science+Business Media, Inc. 2006