Update On The Clinical Perspectives And Care Of The Child With 47,XXY (Klinefelter Syndrome).

47,XXY (Klinefelter syndrome [KS]) is the most common sex chromosomal aneuploidy (1:660), yet, despite this, only 25% of the males are ever diagnosed. Males with 47,XXY present with characteristic symptoms throughout their lifetime with typical physical and neurodevelopmental manifestations focused in growth, cognitive development, endocrine function, and reproduction. Studies have demonstrated that optimal outcomes are dependent on early detection combined with consistent and targeted neurodevelopmental treatment throughout the lifespan. During infancy and into the preschool years, individuals with 47,XXY commonly face deficits in growth and development in the areas of early hormonal, motor, speech, and behavioral development. As they transition into school, the primary neurodevelopmental concerns include language difficulty, executive dysfunction, behavior, and learning and reading deficits. Adults with 47,XXY often present with taller than average height, low levels of fertility, azoospermia, and elevated gonadotropin levels. These presentations may persist from early childhood through adulthood but can be mitigated by appropriate interventions. Early neurodevelopmental and hormonal treatment has been shown to have a minimizing effect on the physical and neurodevelopmental manifestations in individuals with 47,XXY. With innovative and current research studies, the features common to the neurodevelopmental profile of 47,XXY have been further expanded and defined. Further research is necessary to elucidate and understand the relationship between the brain, behavior, and the phenotypic profile of 47,XXY.