Effects of X-monosomy and X-linked imprinting on superior temporal gyrus morphology in turner syndrome

Background: Turner syndrome (TS) results from complete or partial monosomy X. The cognitive phenotype of TS involves preservation of verbal skills with visuospatial functioning deficits. The superior temporal gyrus (STG), which is involved in language capacities, has not been investigated in TS. Methods: The STG was measured in 30 female subjects (mean age = 14.73 ± 6.41; range = 7.56-33.30) with TS and 30 age-matched control subjects (mean age = 14.63 ± 5.90; range = 6.35-32.65) using volumetric magnetic resonance imaging analyses. Results: Right STG, including both gray and white matter volumes, was significantly larger in TS compared with control subjects. Overall left STG volume was not significantly different between groups, although left white matter volume was increased in the TS subjects. The TS subgroup with a maternally derived X chromosome (Xm) demonstrated more aberrant STG volumes compared with subjects with a paternally (Xp) derived X and control subjects. The difference in STG volumes between Xm and control subjects involved both white and gray matter. The Xm subjects differed from Xp subjects only in terms of gray matter. Conclusions: These findings suggest that X-monosomy and X-linked imprinting negatively affect STG development, possibly by disrupting neural pruning mechanisms.