A molecular epidemiologic study of thalassemia using newborns' cord blood in a multiracial Asian population in Singapore: results and recommendations for a population screening program.
DNA technology provides a new avenue to perform neonatal screening tests for single-gene diseases in populations of high frequency. Thalassemia is one of the high-frequency single-gene disorders affecting Singapore and many countries in the malaria belt. The authors explored the feasibility of using PCR-based diagnostic screening on 1,116 unselected sequential cord blood samples for neonatal screening. The cord blood samples were screened for the most common reported alpha- and beta-thalassemia mutations in each ethnic group (Chinese, Malays, and Indians) in a multiracial population. The carrier frequency for alpha-thalassemia mutations was about 6.4% in the Chinese (alpha deletions = 3.9%, alpha deletions = 2.5%), 4.8% in Malays, and 5.2% in Indians. Only alpha deletions were observed in the Chinese. The carrier frequency for beta-thalassemia mutations was 2.7% in the Chinese, 6.3% in Malays, and 0.7% in Indians. Extrapolating to the population distribution of Singapore, the authors found a higher overall expected carrier frequency for alpha- and beta-thalassemia mutations of 9% compared with a previous population study of 6% by phenotype. The highly accurate results make this molecular epidemiologic screening an ideal method to screen for and prevent severe thalassemia in high-risk populations.
Kham
S K
SK
Department of Pediatrics, National University of Singapore, Singapore 119074.
Yin
Shirley Kham Kow
SK
Quah
Thuan Chong
TC
Loong
Ai Mei
AM
Tan
Poh Lin
PL
Fraser
Angus
A
Chong
S S
SS
Chuan
Samuel Chong Siong
SC
Yeoh
A E
AE
Eng-Juh
Allen Yeoh
AY
D002681:China / Q000208:ethnology; D004252:DNA Mutational Analysis; D005006:Ethnicity; D005260:Female; D005312:Fetal Blood; D005838:Genotype; D006801:Humans; D007194:India / Q000208:ethnology; D007231:Infant, Newborn; D008296:Malaysia / Q000208:ethnology; D008297:Male; D015997:Neonatal Screening; D010641:Phenotype; D016133:Polymerase Chain Reaction; D012846:Singapore / Q000453:epidemiology; D017085:alpha-Thalassemia / Q000453:epidemiology* / Q000208:ethnology / Q000235:genetics*; D017086:beta-Thalassemia / Q000453:epidemiology* / Q000208:ethnology / Q000235:genetics*