Blondeau and Dellu-Hagedorn
(pages 1340–1350) investigated new rodent models for subtypes of ADHD, based on behavioral differences between animals in their levels of attention, impulsiveness and motor activity. Four distinct subgroups were demonstrated that parallel those observed in humans: efficient, middle, inattentive and inattentive-impulsive/hyperactive. The study of these subgroups may help to better understand their biological bases and to explain therapeutic effects specific to ADHD subtypes.
Females with Turner Syndrome (TS), a developmental disorder in which one X chromosome is missing or aberrant, exhibit abnormalities in attention as a consequence of reduced X-linked gene dosage. Davies et al.
(pages 1351–1360) show that these abnormalities can be recapitulated in a mouse model of TS, and that they may be alleviated by the addition of a small number of X-linked genes, including steroid sulfatase (Sts
). These data raise important questions about the role of the X chromosome in attention.