ObjectiveTo reveal the familial prevalence and molecular variation of α- and β-globin gene mutations in Guangdong Province.MethodsA total of 40,808 blood samples from 14,332 families were obtained and analyzed for both hematological and molecular parameters.ResultsA high prevalence of α- and β-globin gene mutations was found. Overall, 17.70% of pregnant women, 15.94% of their husbands, 16.03% of neonates, and 16.83% of couples (pregnant women and their husbands) were heterozygous carriers of α- or β-thalassemia. The regions with the highest prevalence were the mountainous and western regions, followed by the Pearl River Delta; the region with the lowest prevalence was Chaoshan. The total familial carrier rate (both spouses were α- or β-thalassemia carriers) was 1.87%, and the individual carrier rates of α- and β-thalassemia were 1.68% and 0.20%, respectively. The total rate of moderate-to-severe fetal thalassemia was 12.78% among couples in which both parents were carriers.ConclusionsThere was a high prevalence of α- and β-thalassemia in Guangdong Province. This study will contribute to the development of thalassemia prevention and control strategies in Guangdong Province.

BackgroundThe identification of cell-free fetal DNA (cffDNA) facilitated non-invasive prenatal screening (NIPS) through analysis of cffDNA in maternal plasma. However, challenges regarding its clinical implementation become apparent. Factors affecting fetal fraction should be clarified to guide its clinical application.ResultsA total of 13,661 pregnant subjects with singleton pregnancies who undertook NIPS were included in the study. Relationship of gestational age, maternal BMI, and maternal age with the cffDNA fetal fraction in maternal plasmas for NIPS was investigated. Compared with 13 weeks (12.74%) and 14–18 weeks group (12.73%), the fetal fraction in gestational ages of 19–23 weeks, 24–28 weeks, and more than 29 weeks groups significantly increased to 13.11%, 16.14%, and 21.17%, respectively (P < 0.01). Compared with fetal fraction of 14.54% in the maternal BMI group of < 18.5 kg/m2, the percentage of fetal fraction in the group of 18.5–24.9 kg/m2 (13.37%), 25–29.9 kg/m2 (12.20%), 30–34.9 kg/m2 (11.32%), and 35–39.9 kg/m2 (11.57%) decreased significantly (P < 0.01). Compared with the fetal fraction of 14.38% in the group of 18–24 years old, the fetal fraction in the maternal age group of 25–29 years old group (13.98%) (P < 0.05), 30–34 years old group (13.18%) (P < 0.01), 35–39 years old group (12.34%) (P < 0.01), and ≥ 40 years old (11.90%) group (P < 0.01) decreased significantly.ConclusionsThe percentage of fetal fraction significantly increased with increase of gestational age. Decreased fetal fraction with increasing maternal BMI was found. Maternal age was also negatively related to the fetal fraction.

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