Aims: Thalassemia is one of the most prevalent inherited disorders in south China. However, there still has no comprehensive research on molecular characterisation of α-thalassemia and β-thalassemia in the Quanzhou region of Fujian province, a city with high incidence of thalassemia in Southeast China. Methods: A total of 11 668 cases were collected in Quanzhou region from January 2013 to June 2019. The deletions of α-thalassemia were detected by Gap-PCR, α-thalassemia and β-thalassemia mutations were detected by DNA reverse dot blot hybridisation. Rare thalassemia gene testing and DNA sequencing were performed to detect rare and novel thalassemia mutation for suspected rare thalassemia carriers. Results: Among 11 668 subjects, 4796 (41.10%) subjects were diagnosed with thalassemia. 3298 (28.27%) subjects were α-thalassemia carriers, 26 types of α-thalassemia mutations were identified, with the common α-thalassemia genotypes being --^SEA/αα (71.47%), -α^3.7/αα (17.13%) and -α^4.2/αα (3.49%). 1407 (12.06%) subjects were β-thalassemia carriers, 18 types of β-thalassemia mutations were identified. The common five genotypes of β-thalassemia were β^IVS-II-654/β^N (36.53%), β^CD41-42/β^N (30.28%), β^CD17/β^N (17.13%), β^CD26/β^N (5.12%) and β^-28/β^N (4.62%). Additionally, 91 (0.78%) subjects with composite α-thalassemia and β-thalassemia were identified. Furthermore, 9 α-thalassemia and β-thalassemia gene mutations (CAP +40–43 (-AAAC), IVS-I-1 (G>T), IVS-I-5 (G>C), SEA-HPFH, CD53 (-T), CD37 (A>G), −90 (C>T), CD3 (T>C), -α^6.9) were identified for the first time in the region. Among them, CD53 (-T), CD37 (A>G) and −90 (C>T) mutations were identified for the first time in Fujian province. Moreover, CD3 (T>C), -α^6.9 mutations were first identified in Chinese individual. Conclusions: Quanzhou region of South China has high incidence of thalassemia mutations. In this study, several cases of rare thalassemia mutations have been identified, providing reference for clinical consultation. The completion of this study is of great significance to strengthen the prevention and control of thalassaemia in the Quanzhou region.

Background: An increase in pathogenic copy number variants (pCNVs) has been recognized to associate with fetal growth restriction (FGR). Here, we aim to explore the application value of chromosomal microarray analysis (CMA) in prenatal diagnosis of FGR.Methods: Prenatal ultrasound was applied to identify FGR. A total of 149 pregnant women with FGR were enrolled in our study. All subjects underwent karyotype analysis and CMA to reveal the chromosomal abnormalities.Results: In this study, all subjects were successfully detected by karyotype and CMA analyses. Of these subjects, the chromosomal abnormalities detection rate was 5.37% (8/149) for karyotyping and 13.42% (20/149) for CMA, respectively. Among them, an 8.05% (12/149) incremental yield of CMA over karyotype analysis was observed (p = 0.004). In addition, a significant difference of pCNV detection rate was observed between the groups with different high-risk factors (p = 0.005). The FGR with structural anomalies group showed the highest pCNV detection rate (33.33%), followed by the FGR with non-structural anomalies group (8.77%) and the isolated FGR group (8.06%).Conclusion: In conclusion, CMA technology showed an effective application value in etiology diagnosis of FGR. We believe that CMA should be recommended as first-line detection technology for prenatal diagnosis in FGR.

Background: Copy number variations (CNVs) can contribute to human phenotype, phenotypic diversity and disease susceptibility, while others may benign. In the current study, an attempt to investigate the pathogenicity of CNVs in chromosome Xp22.31 was explored. Methods: G-banding and SNP-array techniques were used to analyze chromosome karyotypes and CNVs in fetuses. Parents associate with five different pedigrees possessing high risk factors in pregnancy were considered with such parameters as advanced age, high risk of serological screening and ultrasound abnormalities. Results: The fetuses’ amniotic fluid karyotypes were 46, XX and those of their parents with the five pedigrees revealed no abnormalities. Here, we noticed a series of individuals with Xp22.31 duplications ranging from 534.6 kb to 1.6 Mb. It was detected through SNP array that the fetuses in Pedigree 1 and 2 had ~ 600 kb duplications in the Xp22.31 region of their X chromosomes which contained two OMIM genes, HDHD1 (OMIM: 306480) and part of STS (OMIM: 300747). The fetuses of Pedigrees 3, 4 and 5 had 1.6 Mb duplication in the same chromosome which contained four OMIM genes: HDHD1 (OMIM: 306480), STS (OMIM: 300747), PNPLA4 (OMIM: 300102) and VCX (OMIM: 300229). The duplications in the fetuses of Pedigrees 1 and 5 were inherited from the non-phenotypic parents. Pedigrees 3 and 4 refused to perform parental verification. Finally, four of the five pedigrees continue towards pregnancy with no abnormalities being observed during followed-ups. Conclusion: Our study first showed duplications of Xp22.31 in Chinese population. Clinical and genetic investigation on five different pedigrees, we consider the duplication of these fragments as likely benign copy number variants (CNVs). We suggest that the duplications of Xp22.31 with recurrent duplication as a benign CNVs .

Background: An increasing number of techniques have been used for prenatal diagnosis of genetic abnormalities. Our initial objective was to explore the value of the BACs-on-Beads (BoBs) assay for the prenatal diagnosis of aneuploidies and microdeletion/microduplication syndromes in Quanzhou, Southeast China. Methods: A total of 1409 pregnant women with high-risk factors for chromosomal abnormalities admitted to Quanzhou Women’s and Children’s Hospital were enrolled in this study. BoBs assays and karyotype analyses were conducted for all subjects. Subsequently, chromosome microarray analysis (CMA) or fluorescence in situ hybridization (FISH) was performed to validate the findings. Results: In this study, karyotype analysis and BoBs assay failed in 4 cases, and 2 cases, respectively. A total of 1403 cases were successfully analyzed, with success rates of 99.72% (1405/1409) and 99.85% (1407/1409) for karyotype analysis and Bobs assay, respectively. BoBs assay rapidly detected chromosomal aneuploidies in line with the karyotyping data. Additionally, 23 cases of microdeletions/microduplications were detected by BoBs assay but missed by karyotyping, including 22q11.2 microdeletions/microduplications, 5p15.32p15.33 microdeletion, Xp22.31 microdeletions/microduplications, Xq27.3 microdeletion, and Yp11.2 and Yq11.22q11.222 microduplication. In comparison with karyotyping, fewer mosaicisms were identified by BoBs assay. A high detection rate of chromosomal abnormalities was observed in the high-risk group during noninvasive prenatal testing (NIPT) (41.72%) and the abnormal ultrasound group (13.43%). Conclusions: BoBs assay can be used for the rapid and efficient prenatal diagnosis of common aneuploidies and microdeletion/microduplication syndromes. Moreover, the combined use of BoBs assay and karyotyping in prenatal diagnosis may allow for a more effective detection of chromosomal abnormalities.

Third-generation sequencing (TGS) based on long-read technology has been gradually used in identifying thalassemia and hemoglobin (Hb) variants. The aim of the present study was to explore genotype varieties of thalassemia and Hb variants in Quanzhou region of Southeast China by TGS. Included in this study were 6,174 subjects with thalassemia traits from Quanzhou region of Southeast China. All of them underwent common thalassemia gene testing using the DNA reverse dot-blot hybridization technology. Subjects who were suspected as rare thalassemia carriers were further subjected to TGS to identify rare or novel α- and β-globin gene variants, and the results were verified by Sanger sequencing and/or gap PCR. Of the 6,174 included subjects, 2,390 (38.71%) were identified as α- and β-globin gene mutation carriers, including 40 carrying rare or novel α- and β-thalassemia mutations. The αCD30(−GAG)α and Hb Lepore-Boston-Washington were first reported in Fujian province Southeast China. Moreover, the βCD15(TGG> TAG), βIVS−II−761, β0-Filipino(~ 45 kb deletion), and Hb Lepore-Quanzhou were first identified in the Chinese population. In addition, 35 cases of Hb variants were detected, the rare Hb variants of Hb Jilin and Hb Beijing were first reported in Fujian province of China. Among them, one case with compound αααanti3.7 and Hb G-Honolulu variants was identified in this study. Our findings may provide valuable data for enriching the spectrum of thalassemia and highlight the clinical application value of TGS-based α- and β-globin genetic testing.