Mosaic partial trisomy 19p12-q13.11 due to a small supernumerary marker chromosome: a locus associated with Asperger syndrome?

In the neurodevelopmentally impaired population the frequency of small supernumerary marker chromosomes (sSMC) is about 0.3%. To find the origin of a sSMC in a 4-year-old boy with Asperger syndrome (AS) a microarray-based comparative genomic hybridization (aCGH), using a 135K-feature whole-genome microarray, and Metaphase FISH analysis, was performed. The sSMC was characterized as being composed of 18.4 Mb from 19p12q13.11. Based on the size and genic content, it is expected that the partial trisomy detected is responsible for the characteristics observed in the patient. In that case it could be an indication of a novel locus associated with AS.