The amplification refractory mutation system (ARMS): a rapid and direct prenatal diagnostic technique for beta-thalassaemia in Singapore.
beta-Thalassaemia major patients have chronic anaemia and since 3-4 per cent of Singaporeans carry the beta-gene, prenatal diagnosis is essential. We evaluated the amplification refractory mutation system (ARMS) technique as a routine test for prenatal diagnosis of beta-major. Six mutations along the beta-gene were studied--41-42 (-TCTT), IVSII #654 (C-T), 17 beta (A-T), -28 TATA (A-G), IVSI #5 (G-C), and IVSI #1 (G-T). Our results indicate that prenatal diagnosis using these mutations can be offered to 90 per cent (35/39) of our Chinese couples and 54.6 per cent (12/22) of our Malay couples at risk. Confirmation of ARMS results was carried out using allele-specific oligonucleotide hybridization. Prenatal diagnosis using ARMS was successfully carried out in nine cases which included a set of triplets and twins. The triplets were diagnosed with the beta-trait carrying the 41-42 mutation. The couple with twins possessed the #654 mutation and one twin was diagnosed with the beta-trait and the other with #654 homozygosity. Genomic sequencing of the undefined mutations in the Chinese couples revealed rarer mutations at -29 and an ATG-AGG base substitution at the initiation codon for translation. In the Malay couples, genomic sequencing detected mutations at codon 15 (TGG-TAG) and codon 26 (GAG-AAG). We conclude that ARMS with its direct detection of amplified products by gel electrophoresis provides an accurate, rapid, and simpler method for our beta-thalassaemia prenatal diagnosis programme in Singapore.
Tan
J A
JA
Department of Paediatrics, National University of Singapore.
Tay
J S
JS
Lin
L I
LI
Kham
S K
SK
Chia
J N
JN
Chin
T M
TM
Aziz
N B
NB
Wong
H B
HB
D001345:Autoradiography; D004252:DNA Mutational Analysis; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D016133:Polymerase Chain Reaction; D011296:Prenatal Diagnosis / Q000379:methods*; D012846:Singapore / Q000453:epidemiology; D017086:beta-Thalassemia / Q000175:diagnosis* / Q000453:epidemiology