Association of double NOR variant with Turner syndrome.
A study was made of the possible association of double nucleolus organizers (dNORs) with Turner syndrome. Occurrence of dNORs was determined using the silver staining method of Goodpasture and Bloom [1975]. In 45 control subjects, the incidence of dNORs was 8.8%. Studies were done on 33 Turner syndrome patients. In 28 cases with 45,X or 45,X/46,XX karyotypes, the incidence of the dNOR variant was 50%. Five cases of Turner syndrome with X rings or X isochromosomes were negative for dNORs. Analysis of the data indicates an association between the dNOR variant and the occurrence of Turner syndrome. It is proposed that the presence of the dNOR variant can increase the rate of nondisjunction of the X chromosome in meiosis or in mitotic divisions during early gestation.
Jones
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Department of Pediatrics, University of Illinois, Chicago 60612.
Ahmed
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I
Cummings
M R
MR
Rosenthal
I M
IM
D002869:Chromosome Aberrations; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008540:Meiosis; D008938:Mitosis; D009697:Nucleolus Organizer Region / Q000473:pathology*; D014424:Turner Syndrome / Q000235:genetics*