[Analysis of the small supernumerary marker chromosome in Turner syndrome with 45, X/46, X, + mar karyotype].
OBJECTIVE
To identify the origin and study the morphology of small supernumerary marker chromosome (sSMC) in Turner syndrome with 45, X/46, X, + mar karyotype.


METHODS
Using the conventional chromosome G-banding technique, 10 cases of Turner syndrome with 45, X/46, X, + mar chromosome karyotype were obtained, dual-color fluorescence in situ hybridization was applied to study the origin and morphology of the sSMC.


RESULTS
In the 10 cases of Turner syndrome with 45, X/46, X, + mar karyotype, the sSMC of 7 cases was derived from X chromosome [sSMC(X)], the sSMC of 2 cases was derived from Y chromosome [sSMC(Y)] and the remaining 1 case was derived from the autosome. There were 4 cases of ring(r) chromosomes and 3 of centric minutes (min) in the 7 sSMC (X) cases. In the 2 sSMC(Y), one case was dicentric (dic) and the other was centric minute (min). The sSMC originated from the autosome was a centric minute (min).


CONCLUSIONS
The origin of sSMC of Turner syndrome with 45, X/46, X, + mar karyotype was almost all from sex chromosomes, and rarely from autosomes. sSMC can exist as isodicentric, ring, or centric minute. The molecular cytogenetic features of the sSMC can provide useful information for genetic counseling, prenatal diagnosis and treatment of the Turner syndrome patients with a 45, X/46, X, + mar karyotype.
Ye
Zhi-chun
ZC
Institute of Pediatrics, Children's Hospital of Hunan Province, Changsha, Hunan, 410007, P.R. China. greenzhichun@163.com
Cai
Jian-guang
JG
Zhu
Xing-yuan
XY
Zhao
Rui
R
He
Xin-yu
XY
Zhong
Yan
Y
Liu
Kang-xiang
KX
Zhu
Yi-min
YM
D000293:Adolescent; D002648:Child; D002871:Chromosome Banding; D041321:Chromosomes, Human, X / Q000235:genetics*; D041322:Chromosomes, Human, Y / Q000235:genetics; D005260:Female; D005819:Genetic Markers; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D014424:Turner Syndrome / Q000235:genetics*
D005819:Genetic Markers