Application of an optimized interpretation model in capillary hemoglobin electrophoresis for newborn thalassemia screening.

INTRODUCTION: Newborn screening is an important supplement to thalassemia control and prevention. Capillary electrophoresis (CE) technology has several advantages for thalassemia screening but with low sensitivity, especially for thalassemia carriers. This study aims to illustrate the application of an optimized interpretation model in newborn thalassemia screening by capillary hemoglobin electrophoresis. METHODS: Two thousand, two hundred fifty-eight neonates selected from four regions in China were enrolled and were screened for α-thalassemia and ß-thalassemia by capillary electrophoresis. Results were interpreted based on an optimized model integrated with multiple parameters. Molecular analysis was carried out in synchrony and used as the gold standard for the screening performance assessment. The consistency among different regions and thalassemia genotypes were also investigated. RESULTS: Among the 2258 neonates, 485 were identified to have a likely diagnosis of thalassemia, and 422 α-thalassemia, 80 ß-thalassemia, and 21 α/ß-thalassemia cases were confirmed by molecular analysis, including 277 α-thalassemia silent carriers, 135 α-thalassemia trait carriers, 10 Hemoglobin H disease, and 80 ß-thalassemia trait carriers. The screening sensitivity, specificity, positive, and negative predictive value for α-thalassemia and ß-thalassemia were 84.83%, 99.14%, 95.98%, 96.41%, and 88.75%, 98.73%, 76.34%, and 99.48%, respectively. The optimized interpretation model showed higher performance for thalassemia carriers, though some neonates with silent α-thalassemia genotypes (-α3.7 /αα, -α4.2 /αα, and αWS α/αα) and ß-28 /ßN genotype were still missed. The screening performance among different regions was comparable. CONCLUSIONS: Capillary hemoglobin electrophoresis with the optimized interpretation model shows reliable performance for newborn thalassemia screening. It is applicable to large-scale population screening.

[Epidemiological analysis of selected congenital limb malformations in Hengyang].

OBJECTIVE: To describe the epidemiological characteristics of selected congenital limb malformations (CLM) in newborns of Hengyang. METHODS: During the period of 2008-2010, cluster sampling survey was adopted to investigate the congenital limb malformations of neonates born to women resident in Hengyang, including Nanyue District, Zhuhui District, Changning City and Hengshan County. Each newborn was examined for the screening of CLM after birth. Limb malformations were grouped into the isolated (ILM) and the syndromic (SLM) form, depending on associated malformations of the affected. Prevalence rates, CLM spectrum and clinical manifestations were analyzed. RESULTS: A total of 170 CLM cases were identified among 52,307 newborns during the study period, resulting overall rate of 32.50/10(4). The rates for isolated and syndromic CLM were 28.29 and 4.21 per 10 000 births respectively. The rates for polydactyly, congenital talipes equinovarus, syndactyly and limb reduction defects were 13.00/10(4), 9.56/10(4), 5.16/10(4) and 3.63/10(4), respectively. No significant difference in rates of overall CLM or specified CLM was observed across urban-rural, gender and maternal age groups. Of the cases affected by polydactyly, syndactyly and limb reduction defects, malformation involved upper limbs, lower limbs and the both accounted for 68.14%, 14.16% and 17.70%. Preterm birth, low birth-weight, still birth and neonatal death were observed more frequently in syndromic cases than in isolated patients. CONCLUSION: The high CLM prevalence rate and fatality rate in Hengyang suggest that effective measures should be taken to prevent malformations and to improve survival of the affected.