The most common fragile site in man is 3p14

Area of Science:

• Human Genetics
• Cytogenetics
• Molecular Biology

Background:

• A common fragile site (CFS) is known to occur at the 3p14 chromosomal region in humans.
• Understanding the expression and variability of this fragile site is crucial for comprehending chromosomal instability.

Purpose of the Study:

• To investigate the expression of the common fragile site at 3p14 in a cohort of healthy individuals.
• To explore factors influencing the variability of 3p14 fragility expression.

Main Methods:

• Examined chromosome breaks, chromatid breaks, and gaps at 3p14 in 70 normal healthy subjects.
• Utilized fluorescence studies to assess breakage in chromosome No. 3 polymorphisms.
• Analyzed data for influences of sex, age, and environmental factors (methotrexate, fluorodeoxyuridine).

Main Results:

• Fragility at 3p14 was observed in all subjects, with a mean expression of 4% of cells.
• Both copies of chromosome No. 3 showed similar susceptibility to breakage.
• Significant inter-individual and intra-individual variation in 3p14 expression was noted, independent of sex or age.
• High 3p14 fragility correlated with increased lesions at other chromosomal sites.
• Methotrexate and fluorodeoxyuridine significantly enhanced 3p14 and other fragile site expressions.

Conclusions:

• The chromosomal region 3p14 represents the most common fragile site in humans.
• The expression of this common fragile site is influenced by a combination of heritable and environmental factors.
• Further research into 3p14 fragility may provide insights into chromosomal instability syndromes.