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Pulsed-field gradient-gel studies around the fragile site
1New York State Institute for Basic Research In Developmental Disabilities, Staten Island 10314.
American Journal of Medical Genetics
|May 1, 1988
Summary
Structural differences were found between fragile X (fra(X)) chromosomes, potentially explaining linkage heterogeneity with coagulation factor IX (F9). Further analysis is needed to confirm if this is a population variant or linked to fra(X) syndrome.
Area of Science:
- Genetics
- Molecular Biology
- Human Disease Genetics
Background:
- Fragile X syndrome is a genetic disorder with variable expression.
- Linkage heterogeneity between fragile X chromosomes and coagulation factor IX (F9) has been observed.
Purpose of the Study:
- To investigate structural differences in fragile X chromosomes.
- To determine if observed structural variations explain linkage heterogeneity with F9.
Main Methods:
- Pulsed-field gradient-gel electrophoresis (PFGE) was used.
- Analysis involved restriction fragment patterns of large DNA segments.
Main Results:
- A structural difference exceeding 200 kb was identified in the interval between fra(X) and F9 near the DXS105 locus.
- Specific restriction enzyme analyses (Sfi I, Mlu I, Nru I, Sst II) revealed allelic differences.
Conclusions:
- The study identified significant structural variations in fragile X chromosomes.
- These variations may contribute to the observed linkage heterogeneity between fra(X) and F9 loci.
- Further studies are required to ascertain if these differences represent normal population variants or are causative for linkage heterogeneity.