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.

[Prenatal diagnosis and genetic analysis of a rare case with 8p deletion and duplication].

OBJECTIVE: To explore the genetic etiology for a child featuring mental retardation, language delay and autism. METHODS: G-banding chromosomal karyotyping and single nucleotide polymorphism array (SNP-array) were carried out for the child and her parents. RESULTS: The child was found to have a 46,XX,dup(8p?) karyotype, for which both of her parents were normal. SNP-array revealed that the child has harbored a 6.8 Mb deletion in 8p23.3p23.1 and a 21.8 Mb duplication in 8p23.1p12, both of which were verified as de novo pathogenic copy number variants. CONCLUSION: The clinical features of the child may be attributed to the 8p deletion and duplication. SNP-array can facilitate genetic diagnosis for children featuring mental retardation in conjunct with other developmental anomalies.

PTEN expression in human cumulus cells is associated with embryo development competence.

Embryo quality determines the success of in vitro fertilization and embryo transfer (IVF-ET) treatment. Biomarkers for the evaluation of embryo quality have some limitations. Apoptosis in cumulus cells (CCs) is important for ovarian function. PTEN (phosphatase and tensin homolog) is a well known tumour suppressor gene that functions as a mediator of apoptosis and is crucial for mammalian reproduction. In the present study, we analyzed the expression level of PTEN in human CCs and aimed to investigate its association with embryo developmental competence in IVF treatment cycles. The PTEN mRNA level in CCs was measured using real-time fluorescence quantitative PCR. The association of the differential expression of PTEN with embryo quality was analyzed. Our data showed that PTEN mRNA levels were significantly decreased in CCs surrounding mature oocytes compared with immature oocytes. Similar changes were found in the analysis of fertilization and blastocyst formation. The speculation that the measurement of PTEN mRNA levels in human CCs would provide a useful tool for selecting oocytes with greater chances to implant into the uterus needs to be further verified through single-embryo transfer in the future. The proapoptotic mechanism of PTEN in human reproduction needs to be further studied.

[Clinical and genetic analysis of a patient with 10q26.3 microdeletion in conjunct with 18q22.3q23 microduplication].

OBJECTIVE: To explore the genetic etiology for a patient featuring intellectual disability and torticollis. METHODS: Peripheral blood sample was collected from the patient and subjected to G-banded karyotyping analysis and single nucleotide polymorphism array (SNP-array) assay. RESULTS: The patient was found to have a chromosomal karyotype of 46,XX. SNP-array revealed that she has harbored a 3.8 Mb microdeletion at 10q26.3 which has encompassed 21 OMIM genes including EBF3 and ECHS1, and a 7.3 Mb duplication at 18q22.3q23 which has encompassed 19 OMIM genes including TSHZ1 and TXNL4A. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the 10q26.3 deletion was predicted to be pathogenic, whilst the 18q22.3q23 duplication was predicted to be variation of unknown significance. CONCLUSION: The clinical phenotype of the patient may be mainly attributed to the 10q26.3 microdeletion, and haploinsufficiency of the EBF3 gene may account for her intellectual deficiency. Above finding has provided a basis for genetic counseling for the patient.

[Application of chromosomal microarray analysis in the diagnosis of genetic etiology of spontaneous abortions].

OBJECTIVE: To explore the genetic etiology of spontaneous abortions by using chromosomal microarray analysis (CMA). METHODS: Fetal tissues derived from 106 spontaneous abortion samples were subjected to CMA assay to detect genome copy number variants (CNVs). RESULTS: The test was successful in 94 cases (88.68%). Fifty four chromosomal abnormalities were detected, which included 44 numerical chromosomal aberrations mainly consisting of aneuploidies, triploidies and mosaicisms. Four pathogenic CNVs were detected, and two of which involved the Cri-du-chat syndrome regions. In addition, 6 chromosomal mosaicism were detected. CONCLUSION: Numerical chromosomal aberrations and CNVs are the main causes for early spontaneous abortions. CMA can effectively reveal the genetic etiology of spontaneous abortions. Spontaneous abortions at gestational weeks 10 to 11+6 has the highest rate for chromosomal abnormalities, which may provide valuable information for clinical counseling.

[The value of combined detection of HbA2 and HbF for the screening of thalassemia among individuals of childbearing ages].

OBJECTIVE: To assess the application value of combined detection of HbA2 and HbF for the screening of thalassemia among a population of childbearing age in Quanzhou, Fujian, and determine the optimal cut-off values for the region. METHODS: Capillary hemoglobin electrophoresis and genetic testing for α and ß globin gene mutations were simultaneously carried out on 11 428 patients with suspected thalassemia. Statistical methods were used to analyze the distribution of various types of thalassemia and compare the performance of HbA2 and HbF measurement for the screening of various types of thalassemia. The optimal cut-off values for HbA2 and HbF were determined with the ROC curves. RESULTS: 4591 patients with α, ß, and αß compound thalassemia were identified by genetic testing. The most common genotypes for α and ß thalassemia included --SEA/αα and ß654/ßN, ß41-42/ßN, and ß17/ßN. The ROC curves were drawn to compare the performance of HbA2 screening for α-, ß-, αß-compound, static α-, mild α-, and intermediate α-thalassemia, and the maximum area under the curves was 0.674, 0.984, 0.936, 0.499, 0.731, 0.956, and the optimal cut-off values for HbA2 were 2.45%, 3.25%, 3.65%, 2.95%, 2.55%, 1.75%, respectively. CONCLUSION: HbA2 is an efficient indicator for identifying intermediate types of α-, ß-, and αß compound thalassemia. The combination of HbA2 and HbF measurement can effectively detect carriers for ß-thalassemia mutations.

Application of the BACs-on-Beads assay for the prenatal diagnosis of chromosomal abnormalities in Quanzhou, China.

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.

[A case of neonatal Cornelia de Lange syndrome caused by a novel variant of SMC1A gene].

OBJECTIVE: To explore the genetic etiology of a neonate with suggestive features of Cornelia de Lange Syndrome (CdLS). METHODS: Chromosome karyotyping, copy number variation sequencing (CNV-seq) and whole exome sequencing (WES) were carried out for the child. Meanwhile, peripheral venous blood samples were taken from his parents for verifying the suspected pathogenic variants detected in the child. RESULTS: The child has exhibited developmental delay, microcephaly, ptosis, micrognathia, and low ear setting, and was suspected as CdLS. No abnormality was found by karyotyping and CNV-seq analysis. WES has detected 5 heterogeneous variants and 1 hemizygous variant on the X chromosome. Combining the genetic pattern and result of family verification, a hemizygous C.3500T>C (p.ile1167thr) of the SMC1A gene was predicted to underlay the clinical manifestations of the patient. This variant was not recorded in the dbSNP and gnomAD database. PolyPhen2, Provean, SIFT all predicted the variant to be harmful, and PhastCons conservative prediction is was a conservative mutation. ACMG variant classification standard evidence supports are PM2, PP2, and PP3. CONCLUSION: The novel c.3500T>C (p.Ile1167Thr) missense mutation of the SMC1A gene probably underlay the genetic etiology of CdLS in this child. Above results has enriched the mutation spectrum of CdLS type II, and facilitated clinical counseling for this family.

[Non-invasive prenatal testing and genetic diagnosis of a case of Pallister-Killian syndrome].

OBJECTIVE: To apply combined non-invasive prenatal testing (NIPT), chromosomal karyotyping and chromosomal microarray for the screening and prenatal diagnosis of a fetus with supernumerary small marker chromosome (sSMC). METHODS: Standard NIFTY and full gene NIFTY kits were applied to detect free DNA (cfDNA) isolated from peripheral blood sample of a pregnancy woman. Amniocentesis was carried out for the woman for an abnormal NIPT result. G-banded karyotyping and single nucleotide polymorphism array (SNP array) were used to determine the karyotype and copy number variants in the fetus. The result was validated with a fluorescence in situ hybridization (FISH) assay. RESULTS: Both the standard NIFTY and full gene NIFTY indicated abnormal dup(chr12:707 334-33 308 759), for which the T score value of copy number anomaly in full gene NIFTY is 6.823, which is higher than the standard NIFTY's T-score value of 3.9535. The two NIFTY results were both above the normal threshold ± 3. Conventional G-banding analysis of amniocytes showed that the fetus has a karyotype of 47,XY,+mar. SNP-array delineated duplication of 12p (arr [hg19]12p13.33p11.1 (173 786_34 385 641)× 4, which was verified by FISH. Based on the above results, the fetus was diagnosed as a novel case of Pallister-Killian syndrome. CONCLUSION: NIPT has a certain value for the prenatal detection of PKS. Combined use of multiple techniques can facilitate delineation of the source of sSMC.

Combined primary carnitine deficiency with neonatal intrahepatic cholestasis caused by citrin deficiency in a Chinese newborn.

BACKGROUND: Primary carnitine deficiency (PCD) is an autosomal recessive disorder affecting the carnitine cycle and resulting in defective fatty acid oxidation. Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) is an autosomal recessive disorder and one of the main causes of inherited neonatal cholestasis. Both PCD and NICCD are included in the current expanded newborn screening (NBS) targets. CASE PRESENTATION: Targeted exome sequencing was performed on a Chinese proband, and Sanger sequencing was utilised to validate the detected mutations. The patient who was initially suspected to have PCD based on the NBS results presented with neonatal intrahepatic cholestasis and ventricular septal defect. Further investigations not only confirmed PCD but also revealed the presence of NICCD. Four distinct mutations were detected, including c.51C > G (p.F17L) and c.760C > T (p.R254X) in SLC22A5 as well as c.615 + 5G > A and IVS16ins3kb in SLC25A13. CONCLUSIONS: This is the first reported case of PCD and NICCD occurring in the same patient. The dual disorders in a newborn broaden our understanding of inherited metabolic diseases. Thus, this study highlighted the importance of further genetic testing in patients presenting with unusual metabolic screening findings.

[Molecular genetic analysis of a child with de novo 16p11.2 microdeletion].

OBJECTIVE: To explore the genetic basis for a child featuring developmental delay, intelligent disability and language deficit. METHODS: Peripheral blood samples of the child and her parents were collected for routine G-banding karyotyping analysis and single nucleotide polymorphism array (SNP array) detection. Amniotic fluid was also sampled from the mother for karyotyping analysis and SNP array detection. RESULTS: No karyotypic abnormality was found with the child and her parents. SNP array showed that the child has carried a 761.4 kb microdeletion at 16p11.2, while her mother has carried a 444.4 kb microduplication at 15q13.3. Her father's result was negative. Further analysis showed that the 15q13.3 microduplication was inherited from her maternal grandfather who was phenotypically normal. Prenatal diagnosis showed that the fetus has inherited the15q13.3 microduplication from its mother. CONCLUSION: The child has carried a de novo 16p11.2 microdeletion, which overlaps with 16p11.2 microdeletion syndrome region, in addition with similar clinical phenotypes. The 16p11.2 microdeletion probably underlies her abnormal phenotype.

[Clinical and genetic study of a child with 15q11.2 microduplication].

OBJECTIVE: To explore the genetic basis of a child with developmental delay and intellectual disability. METHODS: Peripheral blood samples of the child and his parents were collected for routine G-band karyotyping analysis and single nucleotide polymorphism array (SNP array) assay. Amniotic fluid sample was collected during the next pregnancy for prenatal diagnosis. RESULTS: No karyotypic abnormality was found in the child and his parents. SNP array showed that the child has carried a 855.3 kb microduplication in 15q11.2. His mother carried the same duplication but had no phenotypic anomaly. No microdeletion/microduplication was found in his father. Upon prenatal diagnosis, no abnormalities was found with the chromosomal karyotype and SNP array result of the fetus. CONCLUSION: 15q11.2 microduplication may result in developmental delay and intellectual disability, for which CYFIP1 may be a candidate gene. However, the duplication may increase the risk but with a low penetrance. This should attract attention during clinical consultation.

Molecular analysis of a large novel deletion causing α+-thalassemia.

BACKGROUND: α-thalassaemia is an inherited blood disorder caused by mutations in the α-globin gene cluster. Recognizing the pathogenic α-globin gene mutations associated with α-Thalassemia is of significant importance to thalassaemia's diagnosis and management. METHODS: A family with α-thalassaemia from Fujian, China was recruited for this study. The phenotype was confirmed through haematological analysis. Commercially available Gap-PCR genotypic methods were employed to identify the known deletions causing α-thalassemia. MLPA analysis was used to study the novel mutations; this was then confirmed through DNA sequencing and bioinformatics analysis. RESULTS: The proband of the family belonged to Southeast Asian type (--SEA) thalassaemia. None of the known mutations associated with α-thalassaemia were detected in this family's genetics, whereas a novel 6.9 kb deletion (16p13.3 g.29,785-36,746) covering the α2 gene on the globin gene cluster was identified with MLPA and confirmed through Sanger Sequencing. This data led us to propose a novel pathogenic deletion associated with α-thalassemia: -α6.9 /--SEA. CONCLUSIONS: A novel α-thalassaemia deletion was identified in members of a Chinese family and subsequently analyzed. This finding has helped broaden the spectrum of pathogenic mutations leading to the development of α-thalassaemia, paving the way for improved disease diagnosis and management.

[Analysis a family with partial Xq deletion].

OBJECTIVE: To analyze partial deletion of the long arm of X chromosome in a family and explore the mechanism underlying its phenotypes. METHODS: G-banding technique was employed to analyze the karyotypes of the subjects, and fluorescence in situ hybridization (FISH) was used to analyze their X chromosomes with Xpter, Xqter and WCPX probes. RESULTS: The karyotypes of the proband, her mother and her fetus were all 46,X,del(X)(q24). Combined FISH and karyotyping analysis suggested that the proband and her fetus both carried a Xq24q27.3 deletion. CONCLUSION: The Xq24q27.3 deletion carried by the family is closely related with premature ovarian failure but not with short stature, gonadal dysgenesis and primary amenorrhea.

Prenatal diagnosis of fetuses with absent/hypoplastic nasal bone in second-trimester using chromosomal microarray analysis.

BACKGROUND: Pathogenic copy number variants (pCNVs) are associated with fetal ultrasound anomalies, which can be efficiently identified through chromosomal microarray analysis (CMA). The primary objective of the present study was to enhance understanding of the genotype-phenotype correlation in fetuses exhibiting absent or hypoplastic nasal bones using CMA. METHODS: Enrolled in the present study were 94 cases of fetuses with absent/hypoplastic nasal bone, which were divided into an isolated absent/hypoplastic nasal bone group (n = 49) and a non-isolated group (n = 45). All pregnant women enrolled in the study underwent karyotype analysis and CMA to assess chromosomal abnormalities in the fetuses. RESULTS: Karyotype analysis and CMA detection were successfully performed in all cases. The results of karyotype and CMA indicate the presence of 11 cases of chromosome aneuploidy, with trisomy 21 being the most prevalent among them. A small supernumerary marker chromosome (sSMC) detected by karyotype analysis was further interpreted as a pCNV by CMA. Additionally, CMA detection elicited three cases of pCNVs, despite normal findings in their karyotype analysis results. Among them, one case of Roche translocation was identified to be a UPD in chromosome 15 with a low proportion of trisomy 15. Further, a significant difference in the detection rate of pCNVs was observed between non-isolated and isolated absent/hypoplastic nasal bone (24.44% vs. 8.16%, p < .05). CONCLUSION: The present study enhances the utility of CMA in diagnosing the etiology of absent or hypoplastic nasal bone in fetuses. Further, isolated cases of absent or hypoplastic nasal bone strongly suggest the presence of chromosomal abnormalities, necessitating genetic evaluation through CMA.

Initial clinical and molecular investigation of 20q13.33 microdeletion with 17q25.3/14q32.31q32.33 microduplication in Chinese pediatric patients.

BACKGROUND: Limited research has been conducted regarding the elucidation of genotype-phenotype correlations within the 20q13.33 region. The genotype-phenotype association of 20q13.33 microdeletion remains inadequately understood. In the present study, two novel cases of 20q13.33 microdeletion were introduced, with the objective of enhancing understanding of the genotype-phenotype relationship. METHODS: Two unrelated patients with various abnormal clinical phenotypes from Fujian province Southeast China were enrolled in the present study. Karyotype analysis and chromosomal microarray analysis (CMA) were performed to investigate chromosomal abnormalities and copy number variants. RESULTS: The results of high-resolution G-banding karyotype analysis elicited a 46,XY,der(20)add(20)(q13.3) in Patient 1. This patient exhibited various clinical manifestations, such as global developmental delay, intellectual disability, seizures, and other congenital diseases. Subsequently, a 1.0-Mb deletion was identified in the 20q13.33 region alongside a 5.2-Mb duplication in the 14q32.31q32.33 region. In Patient 2, CMA results revealed a 1.8-Mb deletion in the 20q13.33 region with a 4.8-Mb duplication of 17q25.3. The patient exhibited additional abnormal clinical features, including micropenis, congenital heart disease, and a distinctive crying pattern characterized by a crooked mouth. CONCLUSION: In the present study, for the first time, an investigation was conducted into two novel cases of 20q13.33 microdeletion with microduplications in the 17q25.3 and 14q32.31q32.33 regions in the Chinese population. The presence of micropenis may be attributed to the 20q13.33 microdeletion, potentially expanding the phenotypic spectrum associated with this deletion.

Prenatal diagnosis and molecular cytogenetic characterization of fetuses with central nervous system anomalies using chromosomal microarray analysis: a seven-year single-center retrospective study.

Few existing reports have investigated the copy number variants (CNVs) in fetuses with central nervous system (CNS) anomalies. To gain further insights into the genotype-phenotype relationship, we conducted chromosomal microarray analysis (CMA) to reveal the pathogenic CNVs (pCNVs) that were associated with fetal CNS anomalies. We enrolled 5,460 pregnant women with different high-risk factors who had undergone CMA. Among them, 57 subjects with fetal CNS anomalies were recruited. Of the subjects with fetal CNS anomalies, 23 were given amniocentesis, which involved karyotype analysis and CMA to detect chromosomal abnormalities. The other 34 cases only underwent CMA detection using fetal abortive tissue. In this study, we identified five cases of chromosome aneuploid and nine cases of pCNVs in the fetuses, with a chromosomal aberration detection rate of 24.56% (14/57). In the 23 cases that were given both karyotype and CMA analysis, one case with trisomy 18 was detected by karyotyping. Moreover, CMA revealed a further three cases of pCNVs, including the 1p36.33p36.31, 7q11.23, and 1q21.1q21.2 microdeletions, with a 13.04% (3/23) increase in CMA yield over the karyotype analysis. Additionally, three cases of trisomy 13, one case of trisomy 21, and six cases of pCNVs were detected in the other 34 fetuses where only CMA was performed. Furthermore, a higher chromosomal aberration detection rate was observed in the extra CNS anomaly group than in the isolated CNS anomaly group (40.91% vs 14.29%). In conclude, several pathogenic CNVs were identified in the fetuses with CNS anomalies using CMA. Among the detected CNVs, ZIC2, GNB1, and NSUN5 may be the candidate genes that responsible for fetal CNS anomalies. Our findings provides an additional reference for genetic counseling regarding fetal CNS anomalies and offers further insight into the genotype-phenotype relationship.

Third-generation sequencing identified two rare α-chain variants leading to hemoglobin variants in Chinese population.

BACKGROUND: Rare and novel variants of HBA1/2 and HBB genes resulting in thalassemia and hemoglobin (Hb) variants have been increasingly identified. Our goal was to identify two rare Hb variants in Chinese population using third-generation sequencing (TGS) technology. METHODS: Enrolled in this study were two Chinese families from Fujian Province. Hematological screening was conducted using routine blood analysis and Hb capillary electrophoresis analysis. Routine thalassemia gene testing was carried out to detect the common mutations of α- and ß-thalassemia in Chinese population. Rare or novel α- and ß-globin gene variants were further investigated by TGS. RESULTS: The proband of family 1 was a female aged 32, with decreased levels of mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), Hb A2, and abnormal Hb bands in zone 5 and zone 12. No common thalassemia mutations were detected by routine thalassemia analysis, while a rare α-globin gene variant Hb Jilin [α139(HC1)Lys>Gln (AAA>CAA); HBA2:c.418A>C] was identified by TGS. Subsequent pedigree analysis showed that the proband's son also harbored the Hb Jilin variant with slightly low levels of MCH, Hb A2, and abnormal Hb bands. The proband of family 2 was a male at 41 years of age, exhibiting normal MCV and MCH, but a low level of Hb A2 and an abnormal Hb band in zone 12 without any common α- and ß-thalassemia mutations. The subsequent TGS detection demonstrated a rare Hb Beijing [α16(A14)Lys>Asn (AAG>AAT); HBA2:c.51G>T] variant in HBA2 gene. CONCLUSION: In this study, for the first time, we present two rare Hb variants of Hb Jilin and Hb Beijing in Fujian Province, Southeast China, using TGS technology.

Molecular characterization of similar Hb Lepore Boston-Washington in four Chinese families using third generation sequencing.

Hemoglobin (Hb) Lepore is a rare deletional δß-thalassemia caused by the fusion between delta-beta genes, and cannot be identified by traditional thaltassemia gene testing technology. The aim of this study was to conduct molecular diagnosis and clinical analysis of Hb Lepore in four unrelated Chinese families using third generation sequencing. Decreased levels of mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and an abnormal Hb band were observed in the probands of the four families. However, no common α and ß-thalassemia variants were detected in the enrolled families using polymerase chain reaction-reverse dot blot hybridization based traditional thalassemia gene testing. Further third-generation sequencing revealed similar Hb Lepore-Boston-Washington variants in all the patients, which were resulted from partial coverage of the HBB and HBD globin genes, leading to the formation of a delta-beta fusion gene. Specific gap-PCR and Sanger sequencing confirmed that all the patients carried a similar Hb Lepore-Boston-Washington heterozygote. In addition, decreased levels of MCH and Hb A2 were observed in the proband's wife of family 2, an extremely rare variant of Hb Nanchang (GGT > AGT) (HBA2:c.46G > A) was identified by third-generation sequencing and further confirmed by Sanger sequencing. This present study was the first to report the similar Hb Lepore-Boston-Washington in Chinese population. By combining the utilization of Hb capillary electrophoresis and third-generation sequencing, the screening and diagnosis of Hb Lepore can be effectively enhanced.

Identification of a novel isolated 4q35.2 microdeletion in a Chinese pediatric patient using chromosomal microarray analysis: a case report and literature review.

BACKGROUND: Isolated terminal 4q35.2 microdeletion is an extremely rare copy number variant affecting people all over the world. To date, researchers still have controversial opinions and results on its pathogenicity. Here, we aim to present a Chinese pediatric patient with terminal 4q35.2 microdeletion and use this case to clarify the underlying genotype-phenotype correlation. METHODS: A 17-year-old boy from Quanzhou, South China, was recruited as the main subject in this study. Karyotype and single-nucleotide polymorphism (SNP) based microarray analysis were carried out to detect chromosomal abnormalities and copy number variants in this family. Trio whole exome sequencing (Trio-WES) was performed to investigate the potential pathogenic variant in this family. RESULTS: During observation, we identified abnormal clinical phenotypes including upper eyelid ptosis, motor developmental delay, abnormal posturing, abnormality of coordination, attention deficit hyperactivity disorder, and involuntary movements in the patient. SNP array analysis results confirmed a case of 2.0 Mb 4q35.2 microdeletion and parental SNP array verification results indicated that the terminal 4q35.2 microdeletion was inherited from his mother. No copy number variants were detected in his father. In addition, the trio-WES results demonstrated none of pathogenic or likely pathogenic variants in the patient. CONCLUSIONS: This study brings a novel analysis of a case of 2.0 Mb terminal 4q35.2 microdeletion affecting a Chinese individual. In addition, additional clinical symptoms such as upper eyelid ptosis and involuntary movements were first reported to affect a patient with terminal 4q35.2 microdeletion, which may broaden the phenotype spectrum of the condition.