Fragile X syndrome: diagnosis using highly polymorphic microsatellite markers.
We describe two highly polymorphic microsatellite AC repeat sequences, VK23AC and VK14AC, which are closely linked to the fragile X at Xq27.3. Both VK23AC (DXS297) and VK14AC (DXS292) are proximal to the fragile site. Two-point linkage analysis in 31 fragile X families gave (a) a recombination frequency of 1% (range 0.00%-4%) with a maximum lod score of 32.04 for DXS297 and (b) a recombination frequency of 7% (range of 3%-15%) with a maximum lod score of 12.87 for DXS292. Both of these polymorphisms are applicable to diagnosis by linkage in families with fragile X syndrome. A multipoint linkage map of genetic markers at Xq27.3 was constructed from genotyping these polymorphisms in the CEPH pedigrees. The DXS292 marker is in the DXS98-DXS297 interval and in 3 cM proximal to DXS297.
Richards
R I
RI
Department of Cytogenetics and Molecular Genetics, Adelaide Children's Hospital, North Adelaide, South Australia.
Shen
Y
Y
Holman
K
K
Kozman
H
H
Hyland
V J
VJ
Mulley
J C
JC
Sutherland
G R
GR
D000483:Alleles; D001345:Autoradiography; D001483:Base Sequence; D004247:DNA / Q000235:genetics*; D004276:DNA, Satellite; D005600:Fragile X Syndrome / Q000235:genetics*; D008040:Genetic Linkage; D005819:Genetic Markers; D006801:Humans; D008126:Lod Score; D008969:Molecular Sequence Data; D010375:Pedigree; D011110:Polymorphism, Genetic; D012091:Repetitive Sequences, Nucleic Acid
D004276:DNA, Satellite; D005819:Genetic Markers; D004247:DNA