[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.

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.

The interactions between ineffective erythropoiesis and ferroptosis in ß-thalassemia.

In Guangxi, Hainan, and Fujian Province in southern China, ß-thalassemia is a frequent monogenic hereditary disorder that is primarily defined by hemolytic anemia brought on by inefficient erythropoiesis. It has been found that ineffective erythropoiesis in ß-thalassemia is closely associated with a high accumulation of Reactive oxygen species, a product of oxidative stress, in erythroid cells. During recent years, ferroptosis is an iron-dependent lipid peroxidation that involves abnormalities in lipid and iron metabolism as well as reactive oxygen species homeostasis. It is a recently identified kind of programmed cell death. ß-thalassemia patients experience increased iron release from reticuloendothelial cells and intestinal absorption of iron, ultimately resulting in iron overload. Additionally, the secretion of Hepcidin is inhibited in these patients. What counts is both ineffective erythropoiesis and ferroptosis in ß-thalassemia are intricately linked to the iron metabolism and Reactive oxygen species homeostasis. Consequently, to shed further light on the pathophysiology of ß-thalassemia and propose fresh ideas for its therapy, this paper reviews ferroptosis, ineffective erythropoiesis, and the way they interact.

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.

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.

Mutation analysis of GJB2, SLC26A4, GJB3 and mtDNA12SrRNA genes in 251 non-syndromic hearing loss patients in Fujian, China.

OBJECTIVES: The molecular etiology of non-syndromic hearing loss (NSHL) in Southeastern China (Fujian) has not been precisely identified. our study selected patients with NSHL and analyzed their causative genes, which helped to improve the accuracy of the diagnosis of hereditary hearing loss (HHL) and its treatment. METHODS: 251 unrelated patients who attended the otolaryngology clinic of Fujian Maternal and Child Health Hospital with hearing loss were enrolled to our study. All patients had genetic tests and listening tests, of which 251 were diagnosed with NSHL. In addition, we used whole-exome sequencing (WES) in a patient who has a significant family history of HHL but negative for gene chip testing, as well as in his family members. RESULT: Among of 251 patients, Nucleotide changes were found in 63 cases (25.09%), including 34 located in GJB2(13.5%, including 235delC and 299_300delAT), 13 located in SLC26A4(5.18%, including c.919-2G > A and 2168 A > G), 1 located in GJB3(0.4%,538C > T) and 16 located in mtDNA12SrRNA (6.37%,1555 A > G). In addition, we discuss the process of identifying novel PLS1 mutations from 251 patients. CONCLUSION: Our results demonstrate the conventional deafness gene mutation in 251 NSHL patients in Fujian, China. Compared with the other area of China, we have a lower detection rate, but GJB2 235delC remains the most common mutation in Fujian. In addition, we discuss the process of discovering novel mutation locus for deafness, which provides an understanding for deafness diagnosis and genetic testing.

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.

The clinical value of hsa-miR-190b-5p in peripheral blood of pediatric ß-thalassemia and its regulation on BCL11A expression.

BACKGROUND: The B cell CLL/lymphoma 11A (BCL11A) is a key regulator of hemoglobin switching in ß-thalassemia (ß-thal). Previous study has suggested that dysregulated microRNAs are involved in the regulation of BCL11A expression. The aim of this study was to investigate the clinical value of hsa-miR-190b-5p in ß-thal, and to confirm the regulatory effect of hsa-miR-190b-5p on BCL11A expression. METHODS: The peripheral blood of 25 pediatric ß-thal patients and 25 healthy controls were selected, and qRT-PCR was used to analyze the levels of hsa-miR-190b-5p and BCL11A mRNA. The relationship between hsa-miR-190b-5p expression and hematological parameters was assessed by Pearson's correlation test. The diagnostic power of hsa-miR-190b-5p was evaluated by ROC curves analysis. The direct integration between hsa-miR-190b-5p and BCL11A 3'-UTR was confirmed by luciferase reporter assay. RESULTS: Hsa-miR-190b-5p expression in pediatric ß-thal was upregulated, and negatively correlated with the MCH and HbA levels, but positively correlated with the HbF level. Hsa-miR-190b-5p showed a good diagnostic capability for pediatric ß-thal equivalent to that of HbA2 (AUC: 0.760 vs. 0.758). Moreover, the levels of BCL11A mRNA in pediatric ß-thal were decreased, and hsa-miR-190b-5p had a negative correlation with BCL11A mRNA expression (r = -0.403). BCL11A was a target gene of hsa-miR-190b-5p. The mRNA and protein levels of BCL11A were diminished by introduction of hsa-miR-190b-5p, whereas its expression was upregulated by knockdown of hsa-miR-190b-5p. CONCLUSIONS: Hsa-miR-190b-5p expression was upregulated in pediatric ß-thal and might be an effective diagnostic biomarker. BCL11A was negatively regulated by hsa-miR-190b-5p, which might provide new target for the treatment of pediatric ß-thal.

Identification of a novel 91.5 kb-deletion (αα)FJ in the α-globin gene cluster using single-molecule real-time (SMRT) sequencing.

OBJECTIVES: To present a novel 91.5-kb deletion of the α-globin gene cluster (αα)FJ identified by genetic assay and prenatal diagnosis in a Chinese family. SUBJECTS AND METHODS: The proband was a 34-year-old G3P1 (Gravida 3, Para 1) female at the gestational age of 21+ weeks with a history of an edematous fetus. A routine genetic assay (reverse dot blot hybridization, RDB) was performed to detect common thalassemia mutations. Multiplex ligation-dependent probe amplification (MLPA) and single-molecule real-time technology (SMRT) were used to detect rare thalassemia mutations. RESULTS: The hematological phenotypes of the proband, her mother, elder sister, husband, daughter, and nephew were consistent with the phenotype of α-thalassemia trait. No mutations were found in these family members by RDB, except for the proband's husband who carried an α-globin gene deletion --SEA/αα. MLPA results showed that the proband and other α-thalassemia-suspected relatives had heterozygous deletions around the POLR3K-3-463nt, HS40-178nt, and HBA-HS40-382nt probes. The 5'-breakpoint was out of probe scope and could not be determined. SMRT was performed and a 91.5-kb deletion (NC_000016.10: g.39268_130758del) in the α-globin gene cluster (αα)FJ was identified in the proband and other suspected relatives, which could explain their phenotypes. At the proband's gestational age of 22+ weeks, an amniotic fluid sample was collected and analyzed. As only the 91.5-kb deletion (αα)FJ was identified in the fetus with RDB, MLPA, and SMRT. The proband was suggested to continue the pregnancy. CONCLUSION: We first reported a 91.5-kb deletion (NC_000016.10: g.hg38-chr16:39268-_130758del) of the HS-40 region in the α-globin gene cluster (αα)FJ identified in a Chinese family. Since the HS-40 loss of heterozygosity in combination with the heterozygous deletion --SEA might result in Hb Bart's hydrops fetalis, routine genetic assay, and SMRT were recommended to individuals at risk for prenatal diagnosis.

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.

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.

Molecular genetic analysis of 1,980 cases of male infertility.

The present study aimed to investigate the occurrence of chromosomal karyotype abnormalities and azoospermia factor (AZF) microdeletion on the long arm of the Y chromosome (Yq) in infertile men, and to determine their association with infertility to ultimately improve clinical outcomes in these patients. A total of 1,980 azoospermic and oligospermic men from the outpatient department of the Fujian Maternity and Child Health Hospital (Fuzhou, China) were recruited between January 2016 and December 2019. Peripheral blood was used for karyotype analysis; AZF microdeletion analysis of the Yq was performed using capillary electrophoresis. Among the 1,980 patients, 178 had chromosomal abnormalities (9.0%; 178/1,980), of whom 98 had an abnormal number of chromosomes. Among the abnormal karyotypes, the most common was 47, XXY (80/178; 44.9%). AZF microdeletion on the Yq occurred at a rate of 10.66% (211/1,980); the most common type was the AZFb/c deletion (sY1192; 140/211; 66.4%). The present findings showed that karyotype abnormalities and AZF gene microdeletion are important drivers of male infertility. Specifically, men with Yqh- and del(Y)(q11) had a higher risk of AZF microdeletion. These results suggested that patient treatment could be personalized based on routine molecular genetic analysis, which could further alleviate the economic and emotional burden of undergoing redundant or ineffective treatments.

Sorafenib-Based Drug Delivery Systems: Applications and Perspectives.

As a Food and Drug Administration (FDA)-approved molecular-targeted chemotherapeutic drug, sorafenib (SF) can inhibit angiogenesis and tumor cell proliferation, leading to improved patient overall survival of hepatocellular carcinoma (HCC). In addition, SF is an oral multikinase inhibitor as a single-agent therapy in renal cell carcinoma. However, the poor aqueous solubility, low bioavailability, unfavorable pharmacokinetic properties and undesirable side effects (anorexia, gastrointestinal bleeding, and severe skin toxicity, etc.) seriously limit its clinical application. To overcome these drawbacks, the entrapment of SF into nanocarriers by nanoformulations is an effective strategy, which delivers SF in a target tumor with decreased adverse effects and improved treatment efficacy. In this review, significant advances and design strategies of SF nanodelivery systems from 2012 to 2023 are summarized. The review is organized by type of carriers including natural biomacromolecule (lipid, chitosan, cyclodextrin, etc.); synthetic polymer (poly(lactic-co-glycolic acid), polyethyleneimine, brush copolymer, etc.); mesoporous silica; gold nanoparticles; and others. Co-delivery of SF and other active agents (glypican-3, hyaluronic acid, apolipoprotein peptide, folate, and superparamagnetic iron oxide nanoparticles) for targeted SF nanosystems and synergistic drug combinations are also highlighted. All these studies showed promising results for targeted treatment of HCC and other cancers by SF-based nanomedicines. The outlook, challenges and future opportunities for the development of SF-based drug delivery are presented.

Molecular analysis and prenatal diagnosis of seven Chinese families with genetic epilepsy.

Introduction: Genetic epilepsy is a large group of clinically and genetically heterogeneous neurological disorders characterized by recurrent seizures, which have a clear association with genetic defects. In this study, we have recruited seven families from China with neurodevelopmental abnormalities in which epilepsy was a predominant manifestation, aiming to elucidate the underlying causes and make a precise diagnosis for the cases. Methods: Whole-exome sequencing (WES) combined with Sanger sequencing was used to identify the causative variants associated with the diseases in addition to essential imaging and biomedical examination. Results: A gross intragenic deletion detected in MFSD8 was investigated via gap-polymerase chain reaction (PCR), real-time quantitative PCR (qPCR), and mRNA sequence analysis. We identified 11 variants in seven genes (ALDH7A1, CDKL5, PCDH19, QARS1, POLG, GRIN2A, and MFSD8) responsible for genetic epilepsy in the seven families, respectively. A total of six variants (c.1408T>G in ALDH7A1, c.1994_1997del in CDKL5, c.794G>A in QARS1, c.2453C>T in GRIN2A, and c.217dup and c.863+995_998+1480del in MFSD8) have not yet been reported to be associated with diseases and were all evaluated to be pathogenic or likely pathogenic according to the American College of Medical Genetics and Genomics (ACMG) guidelines. Methods: Based on the molecular findings, we have associated the intragenic deletion in MFSD8 with the mutagenesis mechanism of Alu-mediated genomic rearrangements for the first time and provided genetic counseling, medical suggestions, and prenatal diagnosis for the families. In conclusion, molecular diagnosis is crucial to obtain improved medical outcomes and recurrence risk evaluation for genetic epilepsy.

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.

Application of the Single-Molecule Real-Time Technology (SMRT) for Identification of HKαα Thalassemia Allele.

OBJECTIVE: Single-molecule real-time technology (SMRT) is a sequencing technology using the DNA polymerases and fluorescently tagged nucleotides to accurately sequence DNA strands. The purpose of this study was to evaluate the detection accuracy of SMRT for identification of the Hong Kongαα (HKαα) thalassemia allele. METHODS: We conducted a blinded study of 33 samples of known HKαα alleles. These alleles were detected using SMRT to evaluate accuracy. RESULTS: We conducted a blinded study of 33 known HKαα samples and found all HKαα variants detected by SMRT to be concordant with those independently assigned by gap-polymerase chain reaction (gap-PCR), reverse dot blot hybridization, and 2-round nested PCR. In addition, SMRT detected 2 ß-thalassemia variants that were missed by conventional techniques. CONCLUSION: The results demonstrate that SMRT offers a higher detection accuracy of thalassemia rare and new loci. It is an efficient, reliable, and broad-spectrum test that can be widely used for thalassemia screening in the clinic.

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.

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.

Erythrocyte Indices and Hemoglobin Analysis for α-Thalassemia Screening in an Area with High Carrying Rate.

Carriers of α-thalassemia exhibit hypochromic microcytosis with mean corpuscular volume (MCV) < 80 fL, mean corpuscular hemoglobin (MCH) < 27 pg, and reduced hemoglobin A2 (HbA2). We studied the distribution and diagnostic efficiencies of these indicators and their combinations in patients with and without alpha-thalassemia. Based on genetic diagnosis, 10,883 participants were divided into alpha-thalassemia group (n = 1655) and negative-for-alpha-thalassemia group (n = 9228). Erythrocyte parameters and hemoglobin analysis of the groups were analyzed. Moreover, we compared the four screening schemes (MCV/MCH, MCV/MCH/HbA2, MCV + MCH, MCV + MCH + HbA2) to find the best for α-thalassemia screening. The genotypes of --SEA/αα, and -α3.7/αα are the most prevalent with 54.9% and 27.6% in Fujian Province, China. There were significant differences in the distribution of MCV, MCH, and HbA2 in the two groups. Among the three, MCH exhibited the highest sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy. Although the four screening schemes have their advantages, there are significant differences in their sensitivity and specificity. MCV + MCH had the best diagnostic performance (72.6% sensitivity, 89.0% specificity) as well as the highest Youden index (61.59%). Our results showed that MCH could be used to screen α-thalassemia instead of MCV and HbA2. However, it is recommended that MCV/MCH/HbA2 screening be used in areas with high α-thalassemia incidence to increased sensitivity.