Fragile X full mutations are more similar in siblings than in unrelated patients: further evidence for a familial factor in CGG repeat dynamics.

PURPOSE: We sought to compare patterns of full mutation repeat-length variability in the peripheral blood DNA of patients with fragile X syndrome to determine whether siblings possess mutation patterns more similar than those of unrelated patients. METHODS: Mutation patterns were visualized by Southern blot analysis and captured digitally with a phosphor imager. Novel comparison strategies based on overlapping profile plots and calculation of weighted mean CGG repeat values were used to assess mutation pattern similarity. RESULTS: Within the population that we analyzed of 56 patients with full mutation, mutation patterns were found to be more similar in siblings than in unrelated patients. CONCLUSION: These results indicate that repeat-length variability may be generated in a nonrandom manner and that familial factors influence this process.

Deoxyribonucleic acid (DNA) analysis by restriction fragment length polymorphisms of blood and other body fluid stains subjected to contamination and environmental insults.

Deoxyribonucleic acid (DNA) restriction fragment length polymorphism (RFLP) profile results were obtained from bloodstains and other body fluid stains subjected to mixture with other body fluids, environmental insults (sunlight and temperature), different substrates (cotton, nylon, blue denim, glass, aluminum, and wood), and contaminants (gasoline, bleach, sodium hydroxide, soil, motor oil, detergent, phosphate salt, glacial acetic acid, and microorganisms). Of the samples that produced profile results, all had profiles that were consistent with those of untreated control samples.