Santos Mònica, Mrasek Kristin, Rigola Maria Angels, Starke Heike, Liehr Thomas, Fuster Carme
Unitat de Biologia Cellular i Genètica Mèdica, Facultat de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain.
Fertil Steril. 2007 Oct;88(4):969.e11-7. doi: 10.1016/j.fertnstert.2006.12.073. Epub 2007 Apr 23.
To characterize the small supernumerary marker chromosomes (sSMCs) present in the female member of an infertile couple who has no further clinical symptoms.
Case report.
SETTING(S): Faculty of medicine and institute of human genetics and anthropology.
PATIENT(S): A young, healthy, nonconsanguineous couple asked for genetic evaluation for infertility.
INTERVENTION(S): Intracytoplasmic sperm injection, conventional and molecular cytogenetic analyses.
MAIN OUTCOME MEASURE(S): We characterized the sSMCs present in a woman, who was a member of an infertile couple, by molecular cytogenetic techniques.
RESULT(S): The G-banding technique showed that a marker chromosome was present in some of the examined cells describing the 47,XX,+mar[30]/46,XX[70] karyotype. Subsequently, using new fluorescence in situ hybridization (FISH) techniques, four distinguishable sSMCs (cryptic mosaicism), all derived from chromosome 9, were observed, including minute and ring chromosomes. This heterogeneity was impossible to detect by the conventional G-banding technique or conventional FISH technique that were used before the new FISH techniques (subcentromere-specific multicolor-FISH [subcenM-FISH]) and specific probe for the 9q12 band. In each metaphase with sSMCs, only one or two markers were observed. On the basis of the FISH analyses, the patient's karyotype was defined as 47,XX,+min(9)(:p12-->q12:)/47,XX,+min(9)(:p12-->q12::q12-->p12:)/47,XX,+r(9)(::p12-->q12::)/47,XX,+r(9)(::p12-->q12::p12-->q12::)x2/46,XX.
CONCLUSION(S): The presence of sSMCs derived from chromosome 9 could influence the couple's infertility. The new subcenM-FISH techniques are very useful in the characterization of cryptic mosaicisms of marker chromosomes. Additionally, the hypothesis that the 9p12 chromosomal band is an euchromatic variant region without any phenotypic impact other than possible infertility is supported by this case study since the woman shows a normal phenotype.
对一对不育夫妇中女方所携带的小额外标记染色体（sSMC）进行特征分析，该女方无其他临床症状。
病例报告。
医学院以及人类遗传学与人类学研究所。
一对年轻、健康、非近亲结婚的夫妇因不育前来进行遗传评估。
胞浆内单精子注射、传统及分子细胞遗传学分析。
我们运用分子细胞遗传学技术对一名不育夫妇中的女方所携带的sSMC进行特征分析。
G显带技术显示，在部分检测细胞中存在一条标记染色体，核型描述为47,XX,+mar[30]/46,XX[70]。随后，采用新的荧光原位杂交（FISH）技术，观察到4条可区分的sSMC（隐匿性嵌合体），均源自9号染色体，包括微小染色体和环状染色体。这种异质性无法通过传统的G显带技术或新FISH技术（着丝粒下特异性多色FISH [subcenM-FISH]）及9q12带特异性探针之前所使用的传统FISH技术检测到。在每个含有sSMC的中期相中，仅观察到一两条标记染色体。基于FISH分析，患者的核型定义为47,XX,+min(9)(:p12-->q12:)/47,XX,+min(9)(:p12-->q12::q12-->p12:)/47,XX,+r(9)(::p12-->q12::)/47,XX,+r(9)(::p12-->q12::p12-->q12::)x2/46,XX。
源自9号染色体的sSMC的存在可能影响这对夫妇的不育情况。新的subcenM-FISH技术在标记染色体隐匿性嵌合体的特征分析中非常有用。此外，本病例研究支持了这样一种假设，即9p12染色体带是一个常染色质变异区域，除了可能导致不育外，没有任何表型影响，因为该女性表现出正常的表型。
