title: 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.
abstract: 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.
authors.affiliation: Department of Pediatrics, National University of Singapore, Singapore 119074.
authors.forename: S K
authors.initials: SK
authors.lastname: Kham
authors.forename: Shirley Kham Kow
authors.initials: SK
authors.lastname: Yin
authors.forename: Thuan Chong
authors.initials: TC
authors.lastname: Quah
authors.forename: Ai Mei
authors.initials: AM
authors.lastname: Loong
authors.forename: Poh Lin
authors.initials: PL
authors.lastname: Tan
authors.forename: Angus
authors.initials: A
authors.lastname: Fraser
authors.forename: S S
authors.initials: SS
authors.lastname: Chong
authors.forename: Samuel Chong Siong
authors.initials: SC
authors.lastname: Chuan
authors.forename: A E
authors.initials: AE
authors.lastname: Yeoh
authors.forename: Allen Yeoh
authors.initials: AY
authors.lastname: Eng-Juh
mesh_terms: 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*