Premium
MISDIAGNOSIS OF HOMOZYGOUS ALPHA‐THALASSAEMIA 1 MAY OCCUR IF POLYMERASE CHAIN REACTION ALONE IS USED IN PRENATAL DIAGNOSIS
Author(s) -
KO TSANGMING,
TSENG LIHUI,
HWA HSIAOLIN,
HSU PIMEI,
LI SHWUFAN,
CHU JOYU,
LU PEIJEN,
LEE TZUYAO,
CHUANG SOUMING
Publication year - 1997
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/(sici)1097-0223(199706)17:6<505::aid-pd104>3.0.co;2-r
Subject(s) - polymerase chain reaction , prenatal diagnosis , fetus , heterozygote advantage , contamination , biology , microbiology and biotechnology , dna , gene , genetics , pregnancy , genotype , ecology
The polymerase chain reaction (PCR) is a quite sensitive diagnostic tool but its specificity may be hampered because of contamination of foreign DNA. In order to determine the diagnostic accuracy of PCR in diseases due to gross gene deletion, a total of 180 fetuses at risk of homozygous South‐East Asian deletion (SEA) of alpha‐globin genes were included for study. Both PCR and Southern hybridization (SH) were performed. By PCR, three of 43 affected fetuses were misdiagnosed as heterozygotes; four of 50 normal fetuses were misdiagnosed as heterozygotes; and four of 87 heterozygotes were misdiagnosed, two as normal and two as affected. Misdiagnosis in affected and normal fetuses was most likely due to maternal DNA contamination, while misdiagnosis in heterozygotes was probably due to a failed PCR. In the experiments with PCR in which we added DNA from a carrier woman to an affected or a normal fetus, a level of 1/64 and 1/16 contamination resulted in the appearance of normal and SEA breakpoint sequences, respectively. In the SH experiments using artificially contaminated DNA, a level of 1/4 contamination showed the normal and SEA bands, respectively, while a contamination level lower than 1/8 and 1/16 respectively did not reveal contamination bands. The high sensitivity of PCR makes it easier to amplify contaminated DNA. For accurate prenatal diagnosis, PCR should be performed very carefully and SH seems to be a useful back‐up. © 1997 John Wiley & Sons, Ltd.