Incomplete EcoRI digestion may lead to false diagnosis of fragile X syndrome.
Molecular diagnosis of fragile X syndrome is usually performed using Southern blot analysis of DNA digested with EcoRI. In the course of diagnostic studies, we observed that a specific EcoRI restriction site in the fragile X gene (FMR1) is sometimes refractory to digestion, generating additional fragments on a Southern blot suggestive of a full mutation in FMR1. This may lead to a false-positive diagnosis of fragile X syndrome. Such additional bands are avoided by the use of HindIII instead of EcoRI. Therefore, we recommend the use of HindIII for the molecular diagnosis of fragile X syndrome.
Storm
K
K
Department of Medical Genetics, University of Antwerp, Belgium.
Handig
I
I
Reyniers
E
E
Oostra
B A
BA
Kooy
R F
RF
Willems
P J
PJ
D015139:Blotting, Southern / Q000379:methods; D015246:Deoxyribonuclease EcoRI / Q000378:metabolism*; D015247:Deoxyribonuclease HindIII / Q000378:metabolism; D005189:False Positive Reactions; D005600:Fragile X Syndrome / Q000175:diagnosis* / Q000235:genetics*; D006801:Humans; D009154:Mutation; D015183:Restriction Mapping / Q000379:methods
D015246:Deoxyribonuclease EcoRI; D015247:Deoxyribonuclease HindIII