Regulation of N6-methyladenosine modification in erythropoiesis and thalassemia.

In eukaryotic RNA, N6-methyladenosine (m6A) is a prevalent form of methylation modification. The m6A modification process is reversible and dynamic, written by m6A methyltransferase complex, erased by m6A demethylase, and recognized by m6A binding proteins. Through mediating RNA stability, decay, alternative splicing, and translation processes, m6A modification regulates gene expression at the post-transcriptional level. Erythropoiesis is the process of hematopoietic stem cells undergoing proliferation, a series of differentiation and maturation to form red blood cells (RBCs). Thalassemia is a common monogenic disease characterized by excessive production of ineffective RBCs in the peripheral circulation, resulting in hemolytic anemia. Increasing evidence suggests that m6A modification plays a crucial role in erythropoiesis. In this review, we comprehensively summarize the function of m6A modification in erythropoiesis and further generalize the mechanism of m6A modification regulating ineffective erythropoiesis and fetal hemoglobin expression. The purpose is to improve the understanding of the pathogenesis of erythroid dysplasia and offer new perspectives for the diagnosis and treatment of thalassemia.

Peripheral blood circular RNA circ-0008102 may serve as a novel clinical biomarker in beta-thalassemia patients.

Circular RNA circ-0008102 has previously been found dysregulated in ß-thalassemia (ß-thal) in circRNAs microarray (GSE196682 and GSE241141). Our study is aimed at identifying whether circ-0008102 could be a novel biomarker in ß-thal. The peripheral blood of pediatric ß-thal patients with (n = 39) or without (n = 20) blood transfusion and healthy controls (n = 30) was selected. qRT-PCR, ROC curve analysis, Spearman correlation analysis, and FISH were used to analyze clinical value of circ-0008102. qRT-PCR confirmed that circ-0008102 expression in pediatric ß-thal patients without blood transfusion was significantly higher. ROC curves analysis showed that the AUC of circ-0008102 for differentiating patients without blood transfusion from patients with blood transfusion and healthy controls with an AUC of 0.733 and 0.711. Furthermore, circ-0008102 expression was positively correlated with the levels of RBC, HbF, ß-globin, and γ-globin mRNA, but was negatively corrected with the levels of HbA and Cr. circ-0008102 was mainly located in the cytoplasm. circ-0008102 could induce the activation of γ-globin and negatively regulate the expression of the five highest-ranking candidate miRNAs (miR-372-3p, miR-329-5p, miR-198, miR-152-5p, and miR-627-3p) in K562 cells. CONCLUSION: We demonstrate that peripheral blood upregulated circ-0008102 may serve as a novel clinical biomarker for pediatric ß-thal without blood transfusion. WHAT IS KNOWN: • CircRNAs are known to be involved in various human diseases, and several circRNAs are regarded as a class of promising blood-based biomarkers for detection of ß-thal. • CircRNAs exert biological functions by epigenetic modification and gene expression regulation, and dysregulated circRNAs in ß-thal might be involved in the induction of HbF in ß-thal. WHAT IS NEW: • Peripheral blood circ-0008102 maybe serve as a novel clinical biomarker for detection of pediatric ß-thal without blood transfusion. • Circ-0008102 participates in the pathogenesis of ß-thal through regulating γ-globin expression, and negatively regulates the expression of miR-372-3p, miR-329-5p, miR-198, miR-152-5p and miR-627-3p.

First Report of Filipino ß0-Thalassemia/ß-Thalassemia in a Chinese Family.

A pregnant woman living in Fujian Province, southeastern China, presented due to a risk of having a baby with ß-thalassemia major, during her second pregnancy, since she and her husband were suspected as ß-thalassemia carriers and their affected daughter was a transfusion-dependent patient. Using the common α-thalassemia and ß-thalassemia genotypes test, the pregnant woman was diagnosed as a ß-thalassemia carrier with ßIVS-2 - 654 (C→T)/ßN genotype and her daughter had a homozygosity for IVS - 2 - 654 (C→T) mutation, however, no abnormalities were detected in her husband. SMRT identified a Filipino ß0-deletion in her husband, and MLPA also revealed an unknown deletion in the HBB gene. Electrophoresis showed approximately 350 bp of the PCR product, and the ß-Filipino genotype presented novel fracture fragments ranging from 5,112,884 to 5,231,358 bp, and lacked a 118,475 bp fragment relative to the wild-type sequence. The daughter was therefore diagnosed with the ßIVS-2 - 654 (C→T)/ßFilipino genotype. Prenatal diagnosis with umbilical cord blood at 27th week of gestation showed heteroztgosity for IVS - 2 - 654 (C→T) mutation in the fetus and continued pregnancy was recommended. In conclusion, we identified the Filipino ß0-deletion in a Chinese family, from Fujian area, for the first time, during prenatal screening.

[Advance of research on the role of BCL11A in the occurrence and treatment of ß-Thalassemia].

ß-Thalassemia is a single-gene disease caused by mutations in ß-globin and has a distinct geographical characteristics. Current treatment for patients with moderate to severe thalassemia has mainly relied on long-term blood transfusion and/or hematopoietic stem cell transplantation. B cell lymphoma/leukemia 11A (BCL11A) as a transcriptional repressor plays a vital role in monitoring γ/ß hemoglobin switching, maintaining the normal function of hematopoietic stem cells, and regulating erythrocyte differentiation and lymphocyte development. With the rapid progress in gene editing technology, the BCL11A as a therapeutic target for ß-thalassemia has shown promising results. This article has systematically summarized the regulatory mechanism and therapeutic potential of the BCL11A, with an aim to provide new ideas for the treatment of ß-thalassemia.

Pathogenic copy number variations are associated with foetal short femur length in a tertiary referral centre study.

Shortened foetal femur length (FL) is a common abnormal phenotype that often causes anxiety in pregnant women, and standard clinical treatments remain unavailable. We investigated the clinical characteristics, genetic aetiology and obstetric pregnancy outcomes of foetuses with short FL and provided a reference for perinatal management of such cases. Chromosomal microarray analysis was used to analyse the copy number variations (CNV) in short FL foetuses. Of the 218 foetuses with short FL, 33 foetuses exhibited abnormal CNVs, including 19 with pathogenic CNVs and 14 with variations of uncertain clinical significance. Of the 19 foetuses with pathogenic CNVs, four had aneuploidy, 14 had deletions/duplications, and one had pathogenic uniparental diploidy. The 7q11.23 microdeletion was detected in three foetuses. The severity of short FL was not associated with the rate of pathogenic CNVs. The duration of short FL for the intrauterine ultrasound phenotype in foetuses carrying a pathogenic CNV was independent of the gestational age. Further, maternal age was not associated with the incidence of foetal pathogenic CNVs. Adverse pregnancy outcomes occurred in 77 cases, including termination of pregnancy in 63 cases, postnatal dwarfed foetuses with intellectual disability in 11 cases, and three deaths within 3 months of birth. Pathogenic CNVs closely related to foetal short FL were identified, among which the 7q11.23 microdeletion was highly associated with short FL development. This study provides a reference for the perinatal management of foetuses with short FL.

A novel PLS1 c.981+1G>A variant causes autosomal-dominant hereditary hearing loss in a family.

The fimbrin protein family contains a variety of proteins, among which Plastin1 (PLS1) is an important member. According to recent studies, variations in the coding region of the PLS1 gene are associated with the development of deafness. However, the molecular mechanism of deafness caused by PLS1 gene variants remains unknown. Whole-exome sequencing was performed on hearing-impaired family members and hearing family members to identify pathogenic variants, followed by Sanger sequencing. A minigene assay was conducted to investigate the effect of the variant on PLS1 mRNA splicing. The pathogenicity of the variant was further investigated in zebrafish. RNA-sequencing (RNA-seq) was performed to analyze the dysregulation of downstream signaling pathways caused by knockdown of PLS1 expression. We identified a novel variant, PLS1 c.981+1G>A, in a large Chinese family with hearing loss and showed that the variant is responsible for the occurrence of hearing loss by inducing exon 8 skipping. The variant caused abnormal inner ear phenotypes, characterized by decreases in the mean otolith distance, anterior otolith diameter, posterior otolith diameter, cochlear diameter, and swimming speed and distance in zebrafish. Furthermore, silencing PLS1 expression significantly upregulated the expression of genes in the PI3K-Akt signaling pathway, including Col6a3, Spp1, Itgb3 and hepatocyte growth factor (Hgf). PLS1 c.981+1G>A is a novel pathogenic variant causing hearing loss by inducing exon 8 skipping. Upregulation of the expression of genes in the PI3K-Akt signaling pathway plays an important role in the pathogenesis caused by variants in the PLS1 gene.

Activating transcription factor 4 in erythroid development and [Formula: see text]-thalassemia: a powerful regulator with therapeutic potential.

Activating transcription factor 4 (ATF4) is a fundamental basic region/leucine zipper transcription factor, responds to various stress signals, and plays crucial roles in normal metabolic and stress response processes. Although its functions in human health and disease are not completely understood, compelling evidence underscores ATF4 is indispensable for multiple stages and lineages of erythroid development, including the regulation of fetal liver hematopoietic stem cells, induction of terminal erythroid differentiation, and maintenance of erythroid homeostasis. [Formula: see text]-Thalassemia is a blood disorder arising from mutations in the [Formula: see text]-globin gene. Reactivating the expression of the [Formula: see text]-globin gene in adult patients has emerged as a promising therapeutic strategy for ameliorating clinical symptoms associated with [Formula: see text]-thalassemia. Recent research has suggested that ATF4 contributes to decreased fetal hemoglobin (HbF) level through its binding to potent negative regulators of HbF, such as BCL11A and MYB. Notably, evidence also suggests a contrasting outcome where increased ATF4 protein levels are associated with enhanced HbF at the transcriptional level. Consequently, the identification of mechanisms that modulate ATF4-mediated [Formula: see text]-globin transcription and its effects on erythroid development may unveil novel targets for [Formula: see text]-thalassemia treatment.

Analysis of retest reliability for pregnant women undergoing cfDNA testing with a no-call result.

BACKGROUND: Determining the reasons for unreportable or no-call cell-free DNA (cfDNA) test results has been an ongoing issue, and a consensus on subsequent management is still lacking. This study aimed to explore potential factors related to no-call cfDNA test results and to discuss whether retest results are reliable. METHODS AND RESULTS: This was a retrospective study of women with singleton pregnancies undergoing cfDNA testing in 2021. Of the 9871 pregnant patients undergoing cfDNA testing, 111 had a no-call result, and their results were compared to those of 170 control patients. The no-call rate was 1.12% (111/9871), and the primary cause for no-call results was data fluctuation (88.29%, 98/111). Medical conditions were significantly more frequent in the no-call group than in the reportable results group (P < 0.001). After retesting, 107 (107/111, 96.40%) patients had a result, and the false-positive rate (FPR) of retesting was 10.09% (10.09%, 11/109). In addition, placental lesions were more frequent in the no-call group than in the reportable results group (P = 0.037), and 4 patients, all in the no-call group, experienced pregnancy loss. CONCLUSIONS: Pregnant women with medical conditions are more likely to have a no-call result. A retest is suggested for patients with a no-call result, but retests have a high FPR. In addition, pregnant women with a no-call result are at increased risk of adverse pregnancy outcomes. In conclusion, more attention should be given to pregnant women for whom a no-call cfDNA result is obtained.

Application of the prenatal BACs-on-Beads™ assay for rapid prenatal detection of sex chromosome mosaicism.

The prenatal BACs-on-Beads™ (BoBs) assay was introduced for rapid detection of abnormalities of chromosomes 13, 18, 21, X, and Y and specific nine significant microdeletion syndromes. The ability of prenatal BoBs to detect mosaicism ranged from 20 to 40%. However, there have been no prenatal studies of sex chromosome mosaicism in prenatal BoBs. Therefore, the present study was performed with an aim to uncover the detection level of sex chromosome mosaicism that application of prenatal BoBs assay, and then to assess the sensitivity of prenatal BoBs assay, thereby improving the prenatal diagnostic accuracy. A total of 31 samples of amniotic fluid (AF) and umbilical cord blood (UCB) for prenatal diagnosis were collected, and the results were confirmed through karyotyping, single nucleotide polymorphism microarray (SNP-array) and copy number variation sequencing (CNV-seq). 23 cases of sex chromosome mosaicism were prompted abnormal by prenatal BoBs, the minimum detection level of mosaicism was about 6% as detected by karyotype. The overall sensitivity of prenatal BoBs in the detection of sex chromosome mosaicism was 74.2% (23/31). This study evaluated the effectiveness of prenatal BoBs for detecting sex chromosome mosaicism in prenatal diagnosis, and the results will provide valuable information for genetic counseling.

Prenatal diagnosis of fetuses with region of homozygosity detected by single nucleotide polymorphism array: a retrospective cohort study.

Region of homozygosity (ROH) is classified as uniparental disomy (UPD) or identity by descent, depending on its origin. To explore the clinical relevance of ROH in prenatal diagnoses, we reviewed 5063 fetal samples subjected to single nucleotide polymorphism array at our center over 5 years. ROH cases meeting our reporting threshold were further analyzed. ROHs were detected in 22 fetuses (0.43%, 22/5063), of which, 77.3% (17/22) showed a ROH on a single chromosome and 22.7% (5/22) showed multiple ROHs on different chromosomes. Among 5063 fetuses undergoing invasive prenatal diagnoses owing to various indications, five cases were identified as UPDs with a rate of ~1/1000. We observed clinically relevant UPDs in two cases related to Prader-Willi syndrome and transient neonatal diabetes mellitus. Of note, one case showed 50% mosaicism for trisomy 2 in amniotic fluid, whereas a complete UPD (2) was observed in umbilical cord blood. Trio whole-exome sequencing was performed for three cases. Clinically relevant variants were identified in two cases, one of which, NM_000302:c.2071_2072insCC (p.R693Qfs*122) in PLOD1 located in the ROH, may be related to Ehlers-Danlos syndrome, kyphoscoliotic type, 1. Overall, 72.7% (16/22) of the ROH carriers showed ultrasound abnormalities, of whom eight (50%, 8/16) had adverse perinatal outcomes. Our study demonstrates that the clinical relevance of ROHs should be examined regarding fetuses with ROHs occurring on imprinted chromosomes or those derived from consanguineous parents in prenatal diagnoses; imprinting disorders and/or autosomal recessive diseases attributed to ROHs should be considered during genetic counseling.

Genetic research and clinical analysis of ß-globin gene cluster deletions in the Chinese population of Fujian province: A 14-year single-center experience.

BACKGROUND: Heterozygotes of HPFH and 뫧 thalassemia are clinically asymptomatic or have mild hemoglobin (Hb) values. However, when both HPFH and δß-thalassemia are coinherited with heterozygous ß-thalassemia, patients may progress to a clinical phenotype of thalassemia intermedia or thalassemia major. The purpose of this study was to characterize the genotypes and analyze the phenotypes of these disorders in Fujian Province, to offer advice for genetic counseling and accurate prenatal diagnosis in this region. A total of 55 001 subjects were participated in thalassemia screening. 142 subjects with HbF levels ≥10%, before the blood transfusion, were selected for further investigation. METHODS: Multiplex ligation-dependent probe amplification (MLPA) and Gap-PCR were used to screen for three ß-globin gene cluster deletions: Chinese G γ(A γδß)0 thalassemia and Southeast Asia HPFH (SEA-HPFH) deletion and 1357 bp deletion (NG-000007.3:g.69997-71353 del 1357). RESULTS: A total of 142 patients with HbF (≥10%) were enrolled to characterize the molecular basis of ß-globin gene cluster deletions in our study; 22 cases 0.04% (22/55 001) were definitively diagnosed with ß-globin gene cluster deletions. Ten cases were heterozygous for the Chinese G γ(A γδß)0 -thal mutations, 10 cases were heterozygous for SEA-HPFH, and one case was compound heterozygous for SEA-HPFH and the α-thal mutation. The 1357 bp deletion (NG-000007.3:g.69997-71353 del 1357) was detected in one case. Moreover, the hemoglobin A2  levels in patients who were heterozygous for Chinese G γ(A γδß)0 -thal were statistically lower than in cases with SEA-HPFH deletion(p < 0.05). CONCLUSION: In Fujian Province, the prevalence of common ß-globin gene cluster deletions was 0.04%. What's more, the most common ß-globin cluster deletions are the Chinese G γ(A γδß)0 and SEA-HPFH.

Analysis of genotype-phenotype correlation in patients with α-thalassemia from Fujian province, Southeastern China.

BACKGROUND: There is a high carrying rate of α-thalassemia in Fujian province. However, there are few large-scale studies on the correlation between genotype and phenotype in Fujian province. The purpose of this study was to analyze the phenotype and genotype in a cohort of 2923 patients with α-thalassemia in Fujian province, so as to provide reference data for screening and diagnosis of α-thalassemia in Fujian province. METHODS: The genotype of α-thalassemia was detected by PCR reverse dot blot assay, gap-PCR, single PCR, nested PCR, and sequencing. Clinical and hematological indices of 2923 patients were collected, and the correlation between genotype and phenotype was analyzed. RESULTS: Among 10,350 patients, 2923 cases were found with α-thalassemia, with a detection rate of 28.24%. Among them, --SEA /αα was the most common genotype, accounting for 64.80%. In addition, rare α-thalassemia genotypes were detected in Fujian province, including --THAI /αα (0.41%), HKαα/--SEA (0.03%), and the novel α-thalassemia gene mutation CD5 (GCC>ACC) (HGVS named HBA1: c.16G>A) (0.03%). Patients with deletional genotypes of α-thalassemia were found to have higher RBC and lower Hb, MCV, MCH, and HbA2 than patients with non-deletional genotypes of α-thalassemia (p < 0.05). CONCLUSION: The clinical phenotype of α-thalassemia is influenced by molecular mechanisms. HBA1: c.16G>A mutation is a novel mutation that was first reported in Fujian province, which enriches the human hemoglobin mutation spectrum.

Abnormal regulation of microRNAs and related genes in pediatric ß-thalassemia.

BACKGROUND: MicroRNAs (miRNAs) participate in the reactivation of γ-globin expression in ß-thalassemia. However, the miRNA transcriptional profiles of pediatric ß-thalassemia remain unclear. Accordingly, in this study, we assessed miRNA expression in pediatric patients with ß-thalassemia. METHODS: Differentially expressed miRNAs in pediatric patients with ß-thalassemia were determined using microRNA sequencing. RESULTS: Hsa-miR-483-3p, hsa-let-7f-1-3p, hsa-let-7a-3p, hsa-miR-543, hsa-miR-433-3p, hsa-miR-4435, hsa-miR-329-3p, hsa-miR-92b-5p, hsa-miR-6747-3p and hsa-miR-495-3p were significantly upregulated, whereas hsa-miR-4508, hsa-miR-20a-5p, hsa-let-7b-5p, hsa-miR-93-5p, hsa-let-7i-5p, hsa-miR-6501-5p, hsa-miR-221-3p, hsa-let-7g-5p, hsa-miR-106a-5p, and hsa-miR-17-5p were significantly downregulated in pediatric patients with ß-thalassemia. After integrating our data with a previously published dataset, we found that hsa-let-7b-5p and hsa-let-7i-5p expression levels were also lower in adolescent or adult patients with ß-thalassemia. The predicted target genes of hsa-let-7b-5p and hsa-let-7i-5p were associated with the transforming growth factor ß receptor, phosphatidylinositol 3-kinase/AKT, FoxO, Hippo, and mitogen-activated protein kinase signaling pathways. We also identified 12 target genes of hsa-let-7a-3p and hsa-let-7f-1-3p and 21 target genes of hsa-let-7a-3p and hsa-let-7f-1-3p, which were differentially expressed in patients with ß-thalassemia. Finally, we found that hsa-miR-190-5p and hsa-miR-1278-5p may regulate hemoglobin switching by modulation of the B-cell lymphoma/leukemia 11A gene. CONCLUSION: The results of the study show that several microRNAs are dysregulated in pediatric ß-thalassemia. Further, the results also indicate toward a critical role of let7 miRNAs in the pathogenesis of pediatric ß-thalassemia, which needs to be investigated further.

Prenatal diagnosis of thalassemia in 695 pedigrees from southeastern China: a 10-year follow-up study.

Thalassaemia is highly prevalent in southeastern China. This 10-year follow-up study aimed to characterize the genotype and karyotype of thalassaemia in fetal samples derived from thalassemia carriers in Fujian province, southeastern China. A total of 476 prenatal samples from 472 couples carrying α-thalassaemia traits and 224 samples from 223 couples carrying ß-thalassaemia traits were collected for STR analysis, detection of thalassemia genotypes and karyotyping. The common deletional α-thalassemias and rare thalassemia genotypes were detected using Gap-PCR assay, and the common ß-globin gene mutations were detected using PCR-RDB assay. We detected 43.49% prevalence of α-thalassaemia minor, 26.05% prevalence of α-thalassaemia intermediate and major and 1.89% prevalence of rare form among the 476 prenatal samples from couples with α-thalassaemia, and 85 fetuses with ß-thalassemia heterozygote, 16 with homozygote and 21 with double heterozygote, and a rare ßIVS-2-654(C→T) /Chinese Gγ (A γδß)0  genotype among the 224 prenatal samples from couples with ß-thalassemia. Karyotyping showed 7 fetuses with abnormal karyotypes. Totally 153 pregnancies were terminated, and genetic diagnosis of thalassemia using fetal umbilical cord blood following induction of labor showed consistent results with prenatal diagnosis. No thalassemia phenotypes were identified in normal infants half a year after birth, and the infants with α-thalassemia and ß-thalassemia minor had no or mild anemia symptoms, but normal development, while 15 babies with hemoglobin H disease presented moderate anemia symptoms. Our data suggest the pregestational screening of thalassemia, notably compound and rare forms of thalassemia, for couples carrying thalassemia traits.

[Study on clinical features and diagnostic methods of prenatal Wolf-Hirschhorn syndrome].

OBJECTIVE: To investigate the clinical features of fetuses with Wolf-Hirschhorn syndrome(WHS) and explore the diagnostic methods and prenatal ultrasound characteristics and provide evidence for prenatal genetic counseling. METHODS: We retrospectively analyzed 5 cases of WHS fetuses diagnosed from March 2016 to February 2020, and analyzed the results of chromosomal karyotype analysis and chromosomal microarray analysis (CMA) of the fetuses. RESULTS: Five cases of WHS were detected by CMA, four cases were detected by karyotype analysis. Prenatal ultrasound revealed 4 abnormalities, of which 3 had intrauterine growth restriction, and only 1 had abnormalities of the maxillofacial region. The sequence of the fragments was 4p16.3p16.1 with a loss of 6.5 Mb, 4p16.3p15.32 with a loss of 15.6 Mb combined with 2p25.3 increased by 906kb, 4p16.3p15.31 with a loss of 20.4 Mb, 4p16.p15.1 with a loss of 35 Mb and 4p16.3p14 with a loss of 37 Mb. CONCLUSION: Fetal growth restriction may be one of the early manifestations of WHS. Absence of fetal facial abnormality by prenatal ultrasound screening cannot exclude WHS. Karyotype analysis may miss the diagnosis of WHS, while combined CMA techniques can improve the diagnostic accuracy.

First report of the spectrum of δ-globin gene mutations among women of reproductive age in Fujian area-Discrimination of δ-thalassemia, α-thalassemia, and Iron Deficiency Anemia.

BACKGROUND: Low HbA2 level is an underlying of δ-thalassemia, α-thalassemia, and IDA. Interactions of these disorders can generate a wide spectrum of phenotype, which will pose diagnostic conundrum for clinical assessment, carrier screening, and genetic counseling. METHODS: Subjects with HbA2 levels below 2.0% with normal or reduced hematological parameters were recruited for further investigation. δ-globin gene mutations were identified by DNA sequencing of the HBD gene. Serum ferritin (SF) concentration was determined by the chemiluminescent microparticle immunoassay. The three common deletional α-thalassemia (--SEA /αα, -α3.7 /αα, and -α4.2 /αα) were detected using Gap-PCR, detection of the point mutations in the three nondeletional α-thalassemia (αCS α/αα,αQS α/αα,αWS α/αα), and the 17 common ß-thalassemia was performed using reverse dot blot hybridization (RDB). RESULTS: We had characterized the δ-globin gene mutations in 20 cases, revealing a frequency of 0.4% in the women of reproductive age (20/4 792). Two previously known mutations:-77 T > C and -30 T > C and 3 novel δ-globin gene defects: -44G > A,CD87C > T, and CD134T > A were found. In the selected cases, we also found 85 cases confirmed with (51.2%,85/166) IDA and 39 cases (23.5%,39/166) with common α-thalassemia. Subjects with δ-thalassemia had statistically higher levels of Hb, MCV, and MCH compared with other two groups, whereas statistically lower levels of RDW were seen in δ-thalassemia group. What's more, statistically higher levels of SF were seen in δ-thalassemia group, compared with IDA groups. CONCLUSION: We reported the spectrum of δ-thalassemia mutations for the first time with the frequency of 0.4% among women of reproductive age in Fujian area and found that -77T > C mutation was the most common mutation, followed by -30T > C mutation. What's more, 3 novel δ-globin gene defects: -44G > A,CD87C > T and CD134T > A were found. A thorough analysis of the hematological, electrophoretic characterization, and the level of SF was needed to suspect and further investigate the existence of IDA, α-thalassemia, and δ-thalassemia.

X-linked ichthyosis: Molecular findings in four pedigrees with inconspicuous clinical manifestations.

BACKGROUND: X-linked ichthyosis (XLI) is the second most common type of ichthyosis, which is characterized by wide and symmetric distribution of adherent, dry, and polygonal scales on the skin. Steroid sulfatase (STS) gene, which is located at chromosome Xp22.31, has been identified as the pathogenic gene of XLI. METHODS: In this study, chromosome karyotype analysis, bacterial artificial chromosomes-on-Beads™ (BoBs) assay, fluorescence in situ hybridization (FISH), and single nucleotide polymorphism array (SNP-array) were employed for the prenatal diagnoses in three pregnant women with high-risk serological screening results and a pregnant woman with mental retardation. RESULTS: STS deletion was identified at chromosome Xp22.31 in all four fetuses. Postnatal follow-up confirmed the diagnosis of ichthyosis in two male fetuses and revealed normal dermatological manifestations in other two female fetuses carrying ichthyosis. CONCLUSION: The results of the present study demonstrate that a combination of karyotypying, prenatal BoBs, FISH, and SNP-array may avoid the missed detection of common microdeletions and ensure the accuracy of the detection results, which provides a feasible tool for the reliable etiological diagnosis and better genetic counseling of XLI.

[Analysis of hematological phenotype and genotype of Hb Q-Thailand in Fujian area].

OBJECTIVE: To explore the hematological phenotype and genotype of hemoglobin Q-Thailand in Fujian area. METHODS: Genomic DNA was extracted from peripheral venous blood samples of patients. Suspected samples were screened by hematological parameters analysis and verified with DNA sequencing. RESULTS: In 35 patients suspected with Hb Q-Thailand, 20 were confirmed, which included one case compounded with heterozygous ß CD41-42 mutation and one compounded with Hb New York. CONCLUSION: Analysis of hematological phenotype and genotype of Hb Q-Thailand can faciliate genetic counseling for patients from Fujian area.

[Variant analysis for patients from Fujian area with Hong Kong αα type thalassemia].

OBJECTIVE: To determine the frequency of Hong Kong αα (HK αα) gene in α3.7 positive samples among carriers from Fujian area. METHODS: Routine genetic testing for thalassemia was carried out for 10145 patients with positive screening results. Single PCR and two-round nested PCR were utilized to detect HK αα among 507 patients with α3.7/αα and 2 patients for whom electrophoresis showed α3.7, -αSEA and normal α2 alleles. Reverse dot blot test was used for detecting non-deletional α-thalassemia and ß-thalassemia variants. RESULTS: Among the 507 patients with α3.7/αα, HK αα was identified in 35 cases, which included 25 HK αα/αα, 5 HK αα/α3.7, 4 HK αα/αα with heterozygous CD41/42 (HBB: c.126_129delCTTT) variant, 1 HK αα/αα with IVS-II-654 (HBB: c.316_197C>T) heterozygous variant. One patient was confirmed to have α3.7/anti4.2 genotype. The two cases with α3.7, -αSEA and normal α2 alleles were confirmed to be HK αα/--SEA. The frequency of HK αα genotype in Fujian area was therefore 7.27% among patients with α3.7 and 0.36% in the general population. CONCLUSION: A certain proportion of HK αα has been detected in Fujian area, which will enable more accurate diagnosis and genetic counseling.

Application of the BACs-on-Beads™ assay for rapid prenatal detection application of BoBs™ for PND of aneuploidies and microdeletions.

Prenatal diagnosis focuses on the detection of anatomic and physiologic problems with a foetus before birth. Karyotyping is currently considered the gold standard for prenatal diagnosis of chromosomal abnormalities, but this method can be time consuming. This study evaluated the diagnostic accuracy of the BACs-on-BeadsTM (BoBs™) assay for the rapid diagnosis of aneuploidies and microdeletions. A total of 625 samples from pregnant women in Fujian province, in southeastern China-including three chorionic villus biopsies, 523 amniotic fluid samples, and 99 umbilical-cord centesis samples-were assessed for chromosomal abnormalities by karyotyping and by the BoBs™ assay. A diagnosis was successfully achieved by karyotyping for 98.8% (618/625) and by the BoBs™ assay for 100% (625/625) of the samples. Both assays were concordant for trisomy 21 (2.72%, 17/625), trisomy 18 (1.12%, 7/625), trisomy 13 (0.48%, 3/625), and sex chromosome aneuploidies (0.8%, 5/625). Unlike karyotyping, the BoBs™ assay detected 22q11.2 microdeletion (0.64%, 4/625), 22q11.2 microduplication (0.16%, 1/625), Smith-Magenis syndrome microdeletion (0.16%, 1/625), and Miller-Dieker syndrome microdeletion (0.16%, 1/625). Thus, the BoBs™ assay is a reliable and rapid test for detecting common aneuploidies and microdeletions for prenatal diagnosis, and could be used instead of karyotyping for detection of common aneuploidies as well as to provide additional information regarding microdeletions.