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


CONCLUSIONS
These results indicate that repeat-length variability may be generated in a nonrandom manner and that familial factors influence this process.
Department of Molecular and Medical Genetics, Oregon Health Sciences University, Portland 97201, USA.
R W
RW
Burman
K S
KS
Anoe
B W
BW
Popovich
D015139:Blotting, Southern; D005192:Family Health; D005600:Fragile X Syndrome / Q000235:genetics*; D014644:Genetic Variation; D006801:Humans; D015233:Models, Statistical; D009154:Mutation; D009679:Nuclear Family; D010375:Pedigree; D018911:Trinucleotide Repeats