Klinefelter's syndrome (KS) is due to the presence of one or more supernumerary X chromosomes. Aneuploidy 47,XXY is the most common abnormality of sex chromosomes in humans, with an incidence of 1/500 male live births. Only one-third of subjects with KS is, however, diagnosed. The aim of this work is to present a review of current literature about neurogenetic functions in KS, referring to both clinical and therapeutics aspects. If it is well known that the majority of subjects with 47,XXY karyotype have a normal intellectual level, the identification of strengths and weaknesses of their intellectual functioning is important for the purpose of planning early psycho-educational interventions. Language difficulties are one of the more distinctive traits in cognitive functioning of people with KS. It has also been suggested that the limitations in communication markedly affect social adaptation and behavioral aspects, as well as the development of personality. Moreover, difficulties in learning language appear to be related to an altered functional lateralization; therefore, KS subjects are a suitable model for studying genetic abnormalities of lateralization. In this, perspective psychopathological risk is analyzed. Early recognition of this aspect is needed to address the educational and therapeutic perspectives for KS subjects.