[Retardation of psychomotor development and tremor in a boy with 48,XXYY karyotype].

We report a seven-year-old boy with 48,XXYY karyotype, presenting with tremor and a slight retardation of psychomotor development. Although the physical phenotype is similar to 47,XXY, 48,XXYY is associated with additional medical problems and more significant neurodevelopmental and psychological features. Increased awareness of such features is important to facilitate timely diagnosis and initiation of appropriate screenings and treatments. Karyotyping should be considered in individuals presenting with tremor and a history of develop-mental delay, learning disabilities, tall stature or micro-orchidism.