What fragile X condition requires a folic acid deficient medium for culture?

The fragile X condition specifically requires a folic acid deficient medium for culture due to the unique characteristics of the chromosomes in individuals affected by this condition. Fragile X syndrome is linked to a mutation in the FMR1 gene, which is associated with the repeat expansion of the CGG sequence. When cultured in a folic acid deficient medium, cells exhibit the characteristic fragile site on the X chromosome, allowing for the visualization of these chromosomal abnormalities.

This culturing technique leverages the fact that the fragile site on the X chromosome becomes more apparent under such conditions, making it easier to diagnose fragile X syndrome. The use of a folic acid deficient medium is particularly important because it induces the expression of the fragile site, which may not be noticeable in a standard growth medium where folic acid is present.

The other options, while they pertain to different cytogenetic phenomena, do not involve the specific requirement for a folic acid deficient medium for culturing cells to visualize conditions or abnormalities associated with them. Thus, the specific need for folic acid deficiency in the culture of cells for the diagnosis of fragile X syndrome distinguishes it as the correct answer.