High-level language competencies and Theory of Mind in a group of children with Klinefelter syndrome.

Klinefelter syndrome (KS) is a genetic anomaly involving the presence of one or more supernumerary X chromosomes in male individuals. In the cognitive profile of these individuals, strengths are found in nonverbal abilities, whereas weaknesses are observed in executive function, language, and academic performance. Our study is based on a comparison between eight children diagnosed with KS (47,XXY) (age range: 9-13 years; IQ range: 80-123), with no delay in language development, and eight typically developing (TD) controls.