Effect of Growth Hormone on Early Brain Development in Girls With Turner Syndrome

• Total brain volume [ Time Frame: Change in volume from 12 months of age scan in 24 months of age scan ] [ Designated as safety issue: No ]
  Percent change in total brain volume as determined by magnetic resonance imaging (MRI)
  
  

• Volume of brain lobes [ Time Frame: Change in volume from 12 months of age scan in 24 months of age scan ] [ Designated as safety issue: No ]
  Percent change in volumes of occipital lobes as determined by MRI.
  
  
• White matter tracts [ Time Frame: Change in volume from 12 months of age scan in 24 months of age scan ] [ Designated as safety issue: No ]
  Change in the fractional anisotropy of white matter tracts using Diffusion Tensor Imaging (DTI)
  
  
• Volume of brain lobes [ Time Frame: Change in volume from 12 months of age scan in 24 months of age scan ] [ Designated as safety issue: No ]
  Percent change in volumes of prefrontal lobes as determined by MRI.
  
  
• Volume of brain lobes [ Time Frame: Change in volume from 12 months of age scan in 24 months of age scan ] [ Designated as safety issue: No ]
  Percent change in volumes of frontal lobes as determined by MRI.
  
  
• Volume of brain lobes [ Time Frame: Change in volume from 12 months of age scan in 24 months of age scan ] [ Designated as safety issue: No ]
  Percent change in volumes of temporal lobes as determined by MRI.
  
  
• Volume of brain lobes [ Time Frame: Change in volume from 12 months of age scan in 24 months of age scan ] [ Designated as safety issue: No ]
  Percent change in volumes of parietal lobes as determined by MRI.
  
  

Studies in older children and adults have found that IQ in individuals with Turner syndrome (TS) and the general population are similar. However, many individuals with TS have a nonverbal learning disability which may cause problems with imagining and working with objects in space (for example: building blocks, working puzzles, copying designs, driving a car) as well as problems in planning, paying attention, and getting along with people their own age. Studies of brain structure have found changes in the size and function of specific areas of the brain that are involved in these nonverbal processes. However, there are no data published on brain structure or function in girls with Turner Syndrome in the first few years of life when brains are learning and growing most rapidly.

In a recent study, very young, short girls with Turner Syndrome (TS)(averaging 2 years in age) were treated with Growth Hormone (GH) and almost reached an average height after 2 years. The risks of GH for the young girls in that study appeared to be the same as those for older girls. Therefore, it is now recommended that GH therapy be considered as soon as a child with TS has growth failure. Growth failure often occurs during infancy; therefore, more children with TS are now receiving GH therapy as young as 12 months of age. In this study, the investigators wish to start understanding what effect GH has on learning and brain growth when given between the ages of 12 and 24 months. In this study, the girls with TS will have developmental studies, a physical examination, magnetic resonance imaging (MRI), and blood drawn at one and two years of age. Some of the girls in this study will receive GH from 12 until 24 months of life, while others will not. Brain growth and development will be compared between those who have been treated with GH and those who have not. This is a pilot study in which the investigators will gather data to design a larger study that can answer these questions.