Double aneuploidy involving trisomy 7 with Potter sequence.

We report a prenatal case of double aneuploidy (consisting of chromosome 7 and X) with the features of Potter sequence. Of the stillborn fetus, skin fibroblast cultures were performed and fluorescence in situ hybridization (FISH) technique was also used for further investigation. On physical examination; the fetus was found to have malformed ears, micrognatia, hypertelorism, abnormal extremities, rocker-bottom feet and abnormal external genitalia and polycystic right kidney was seen after an extensive autopsy. As amniocentesis and cordocentesis materials revealed X chromosome mosaicism, trisomy 7 was detected in the skin fibroblast culture of the ex fetus and karyotype evaluated as composite; 46~47,X,+7,-X[cp18]. FISH results confirmed the double aneuploidy and also revealed XX and XXXX cell lines. Comparison with the previously reported cases of trisomy 7 with Potter syndrome suggests a possible link (if not coincidental) between trisomy 7 and Potter syndrome in our case. This is the first reported case of double aneuploidy involving trisomy 7 with the features of Potter syndrome.

Determination of a translocation chromosome by atomic force microscopy.

Atomic force microscopy (AFM) has been used to study the translocation involving chromosomes 11 and 13. An amniocentesis procedure was performed at 18 weeks of pregnancy on a familial balanced translocation carrier mother whose karyotype was 46,XX,t(11;13) (q23;q34). After harvesting the tissue cultures, light microscopy studies (LM) have indicated that the fetus had the same translocation. A 0.3 microm gap region on the derivative chromosome 13 was determined by AFM; it was equivalent to a mid-sized G-band. The enhanced resolution of AFM with respect to its line measure analysis and three-dimensional image capture capability has allowed an extension and reconsideration of conclusions about chromosomal aberrations based on the study of LM preparations. In this manner, chromosomal disorders will be studied at nanoscale to help in the planning of new therapy strategies.