Developing an Animal Counting Game in Second Life for a Young Adult with Down Syndrome.

Down syndrome is caused by trisomy of all or part of human chromosome 21 (HSA21) and is the most common genetic cause of significant intellectual disability. It is the most common chromosome abnormality in humans, occurring in about one per 1000 babies born each year. It is typically associated with physical growth delays, characteristic facial features, and mild to moderate intellectual disability [1].