Validation of primed in situ labeling for interphase analysis of chromosomes 18, X, and Y in uncultured amniocytes.
OBJECTIVE
Primed in situ labeling (PRINS) is an interesting alternative to the traditional fluorescence in situ hybridization (FISH) for the in situ detection of specific sequences in chromosome anomalies. It combines the sensitivity and specificity of the polymerase chain reaction with the specific in situ signal detection capability of FISH.


METHODS
We performed PRINS on uncultured amniocytes and compared the results with standard cytogenetic analysis. In a prospective study, a total of 262 independent samples were analyzed for numerical aberrations of chromosome 18.


RESULTS
In more than 95% of the cases PRINS reactions were successfully achieved. Neither false-positive nor false-negative results were obtained. 62 of the 262 cases were in parallel examined for chromosome 18 aneuploidies by FISH. Although there were significant differences in signal distribution, these did not lead to a different overall classification of the respective cases, i.e., the end results of disomic and trisomic cases for chromosome 18 were identical between FISH and PRINS. In 205 of 262 cases PRINS was performed for chromosomes X and Y. 97.6% of these samples were properly sex differentiated.


CONCLUSIONS
The PRINS assay is a simple and cheap alternative to detect numerical aberrations of chromosome 18. However, the rate of false-positive results for chromosome X was calculated as 1% and the rate of false-negative ones for chromosome Y as 2%. Further investigations are required to transform PRINS into an alternative to conventional methods for routine rapid prenatal diagnosis of gonosomes.
Mennicke
Kirsten
K
Department of Human Genetics, University of Lübeck, Germany. mennicke@medinf.mu-luebeck.de
Yang
Jianbin
J
Hinrichs
Frauke
F
Müller
Andreas
A
Diercks
Petra
P
Schwinger
Eberhard
E
D000650:Amnion / Q000166:cytology* / Q000502:physiology; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics*; D041321:Chromosomes, Human, X / Q000235:genetics*; D041322:Chromosomes, Human, Y / Q000235:genetics*; D005260:Female; D006801:Humans; D007399:Interphase / Q000235:genetics*; D008297:Male; D010865:Pilot Projects; D011247:Pregnancy; D020401:Primed In Situ Labeling / Q000379:methods*