Prenatal diagnosis of trisomy 9 mosaicism: Two new cases

Abstract

We present two prenatal cases of trisomy 9 mosaicism, both of which presented intrauterine growth retardation (IUGR) and other abnormal ultrasound findings. In case A, mosaicism was found in amniotic fluid cell cultures, of which 65 per cent were trisomic cells, on average. In case B, trisomic cells were present in amniotic fluid cell cultures (12 per cent) but none were found in fetal cord blood. After autopsy, cytogenetic findings were confirmed in different tissue cultures. It is concluded that echographic indicators are a very useful tool for a correct prenatal diagnostic interpretation of trisomy 9. Suspected trisomy 9 mosaicism always requires further investigation and fetal cord blood cytogenetic analysis may not be considered as providing an accurate diagnosis of fetal trisomy 9.

Discrepancies in cytogenetic results between amniocytes and postnatally obtained blood: trisomy 9 mosaicism

“…Eleven of the 12 cases exhibited a mosaic karyotype on peripheral blood analysis. However, like the present case, one of the 12 cases reportedly had a normal fetal cord blood karyotype, and analyzes of the skin and lung tissues revealed a mosaic karyotype 47,XY, + 9[17]/46,XY[83] and 47,XY, + 9[14]/46,XY[86], respectively (Merino et al 1993). Moreover, one of the 11 cases had an almost normal fetal cord blood karyotype of 47,XX, + 9[1]/ 46,XX[99], whereas cytogenetic studies of cell cultures obtained at autopsy from several fetal tissues demonstrated trisomy 9 ranging from 12 to 24% (Schwartz et al 1989).…”

“…Eleven of the 12 cases exhibited a mosaic karyotype on peripheral blood analysis. However, like the present case, one of the 12 cases reportedly had a normal fetal cord blood karyotype, and analyzes of the skin and lung tissues revealed a mosaic karyotype 47,XY, + 9[17]/46,XY[83] and 47,XY, + 9[14]/46,XY[86], respectively (Merino et al . 1993).…”

“…Based on the observation reported here, together with those made in two other cases (Schwartz et al . 1989; Merino et al . 1993), we concluded that it is important to be aware of the possibility that the patient can have a normal postnatal blood karyotype and an abnormal phenotype with multiple malformations when mosaic trisomy 9 is detected prenatally.…”

Prenatal confirmation of true fetal trisomy 22 mosaicism by fetal skin biopsy following normal fetal blood sampling

“…Before skin biopsy can be included in the routine evaluation of amniotic fluid mosaicism, there are H Kosztolanyi et al, 1976;Neu et al, 1969;Schinzel et al, 1974;DeBray-Ritzen et al, 1974;Meisel-Stoisiek et al, 1983 9 4 [1] -H Sherer et al, 1992;Merino et al, 1993;Saura et al, 1995;Schwartz et al, 1989 12 2 (1) 2 H Cartolano et al, 1993;von Koskull et al, 1989;Aughton et al, 1996;Patel et al, 1996 15 1 H Pletcher et al, 1994;Lindor et al, 1993;Gilbertson et al, 1990;Hsu et al, 1996 17 1 1 Kingston et al, 1993;Shaffer et al, 199618 -1 Pagon et al, 1979 1 - Hsu et al, 1987 21 -7 [3] 5 Yokoyama et al, 1992;Pagon et al, 1979;Warkany et al, 1964;Ridler et al, 1965;Zellweger et al, 1966;Haberlandt, 1973;Ladda et al, 1977 22 (1) 7 H Our case; Pagon et al, 1979;Wertelecki et al, 1986;Lessick et al, 1988;Lund et al, 1990;Desilets et al, 1996X 1 -Schlesinger et al, 1990 [ ]=Low-level mosaicism present in lymphocytes (<5 per cent); high level present in fibroblast (>50 per cent). ( )=Complete in utero evaluation including amniocentesis, cordocentesis, and skin biopsy.…”

Prenatal diagnosis of trisomy 9: cytogenetic, FISH, and DNA studies

“…Sometimes it poses a serious problem for genetic counselling, since we must distinguish between mosaicism, pseudomosaicism, CPM, and true trisomy 9 (Hsu and Perlis, 1984;Pfeiffer et al, 1984;Appelman et al, 1991;Saura et al, 1995). Prenatal detection of trisomy 9 mosaicism in amniotic fluid can be complicated by the absence of the trisomic cell line in different tissues and the subsequent lack of fetal anomalies in some cases (Hsu and Perlis, 1984;Merino et al, 1993;Pfeiffer et al, 1984). These authors suggested that the trisomic cells may be limited to fetal membranes.…”