Linkage analysis of the fragile X syndrome using a new DNA marker U6.2 defining locus DXS304.
A new RFLP marker U6.2 defining the locus DXS304 was recently mapped to the distal long arm of the X chromosome. In the present study we report the results of genetic linkage analysis of 13 fragile X [fra(X)] families that were informative for the new marker. Analysis of the recombinants for F9-FRAXA, DXS105-FRAXA, DXS98-FRAXA, DXS52-FRAXA, DXS15-FRAXA, and F8C-FRAXA, places DXS304 distal and near to the FRAXA locus. Combined with results from previous studies, our results support the order Xcen.-F9-DXS105-DXS98-FRAXA-DXS304-DXS5 2-DXS15-F8C-Xqter. Close linkage was observed between DXS304 and the disease locus with a peak lod score of 5.12 at theta = 0.04 from the present study and, with a peak lod score of 17.45 at theta = 0.035 when our data are combined with published data from 2 other studies. The present study confirms that U6.2 is useful for prenatal diagnosis and carrier testing in families affected by fra(X) syndrome.
Goonewardena
P
P
Department of Pediatrics, North Shore University Hospital-Cornell University Medical College, Manhasset, N.Y. 11030.
Brown
W T
WT
Gross
A C
AC
Ferrando
C
C
Dobkin
C
C
Romano
V
V
Bosco
P
P
Ceratto
N
N
Pettersson
U
U
Dahl
N
N
D015342:DNA Probes; D005260:Female; D005600:Fragile X Syndrome / Q000235:genetics*; D005819:Genetic Markers; D006801:Humans; D008126:Lod Score; D008297:Male; D010375:Pedigree; D012150:Polymorphism, Restriction Fragment Length; D011995:Recombination, Genetic; D012306:Risk; D012984:Software
D015342:DNA Probes; D005819:Genetic Markers