Two studies of neuroimaging findings in 47,XXX females are currently available, both of adult subjects who had been identified as part of birth cohort studies (for details see description under 47,XXY studies in previous section). Imaging data were acquired from 12 47,XXX females (mean age 21.6 years, SD 3.1 years) who had participated in the Edinburgh birth cohort [Warwick et al., 1999]. The 47,XXX women had significantly lower IQ than controls (47,XXX: mean NART IQ 82.5, SD 7.7; controls 102.8, SD 7.0, P < .0001), and significantly increased scores in three domains of the SIS: introversion, magical thinking, and impulsivity. Whole brain volumes were significantly smaller in the 47,XXX women, as were several regional volumes, although the latter were no longer statistically significant after differences in total brain volume were taken into account. There were also no systematic volumetric asymmetries found between the groups. White matter hyperintensities were found in three of the 47,XXX subjects and none of the healthy controls. There were no correlations between SIS scores and brain volumes, or between IQ and brain volumes within diagnostic groups, although there was a correlation between measures of IQ and total brain volume across females as a whole.
