Open AccessThe cognitive phenotype in Klinefelter syndrome: A review of the literature including genetic and hormonal factors
Author(s) -
Boada Richard,
Janusz Jennifer,
HutaffLee Christa,
Tartaglia Nicole
Publication year - 2009
Publication title -
developmental disabilities research reviews
Language(s) - English
Resource type - Journals
eISSN - 1940-5529
pISSN - 1940-5510
DOI - 10.1002/ddrr.83
Subject(s) - klinefelter syndrome , neuropsychology , cognition , psychology , clinical psychology , developmental psychology , medicine , pediatrics , psychiatry
Abstract Klinefelter syndrome (KS) or 47,XXY occurs in ∼1 in 650 males. Individuals with KS often present with physical characteristics including tall stature, hypogonadism, and fertility problems. In addition to medical findings, the presence of the extra X chromosome can lead to characteristic cognitive and language deficits of varying severity. While a small, but significant downward shift in mean overall IQ has been reported, the general cognitive abilities of patients with KS are not typically in the intellectual disability range. Most studies support that males with KS have an increased risk of language disorders and reading disabilities. Results of other studies investigating the relationship between verbal and nonverbal/spatial cognitive abilities have been mixed, with differing results based on the age and ascertainment method of the cohort studied. Executive function deficits have been identified in children and adults with KS, however, the research in this area is limited and further investigation of the neuropsychological profile is needed. In this article, we review the strengths and weaknesses of previous cognitive and neuropsychological studies in males with KS in childhood and adulthood, provide historical perspective of these studies, and review what is known about how hormonal and genetic factors influence cognitive features in 47,XXY/KS. © 2009 Wiley‐Liss, Inc. Dev Disabil Res Rev 2009;15:284–294.