In cells taken from affected individuals, a fragile site can be visualised near the tip of Xq if the cells are cultured in a low-folate medium.
Major chromosomal abnormalities are detectable using the light microscope. If a disease occurs in association with such a cytogenetic abnormality then it may suggest that the disease gene is in the region involved. For example, the gene involved in fragile-X mental retardation is situated at the "fragile-site" near the tip of the X chromosome.
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In cells taken from affected individuals, a fragile site can be visualised near the tip of Xq if the cells are cultured in a low-folate medium. |
Families have been reported in which a cytogenetic abnormality cosegregates with mental illness, and some cytogenetic abnormalities are associated with high rates of psychosis, so these may point to regions of interest.