Dc. Chu et al., Non-radioactive Southern hybridization for early diagnosis of alpha-thalassemia with Southeast Asian-type deletion in Taiwan, AM J MED G, 95(4), 2000, pp. 332-335
alpha -Thalassemia has been estimated to account for over 60% of hydrops fe
talis cases in Taiwan, The most common genotypic lesion found in ol-thalass
emia-l cases in Taiwan is deletion of a large segment of the ac-globin gene
cluster, termed the Southeast Asian-type deletion (-(SEA)/; further referr
ed to as SEA-type deletion), Seven chorionic villus samples (CVS) from preg
nancies of couples both heterozygous for SEA-type deletion were studied. No
n-radioactive Southern-blot hybridization using the digalkaline phosphatase
detection system was developed to fulfill this purpose. The results were c
ompared with corresponding polymerase chain reaction (PCR) data to elucidat
e the effectiveness of these two protocols in the diagnosis of the SEA-type
deletion. The data showed that of the seven CVS, three demonstrated a dist
inctive band pattern, indicating their homozygous status of SEA-type deleti
on, whereas two showed heterozygous patterns, and the other two were free o
f the deletion, Homozygosity of the deletion was confirmed by Southern-blot
hybridization performed on DNA samples extracted from the abortus tissue.
However, two of the three cases with SEA-type deletion showed heterozygous
PCR results. Maternal cell contamination could be responsible for the artif
acts in the PCR results, but the influence due to the contamination is mini
mal in non-radioactive Southern-blot hybridization, We concluded that PCR i
s suitable for screening of carrier adults with SEA-type deletion, and non-
radioactive Southern hybridization is ideal for early prenatal diagnosis of
the SEA-type deletion. (C) 2000 Wiley Liss, Inc.