Search

* Context.--Identification of rare thalassemia variants requires a combination of multiple diagnostic technologies. Objective.--To investigate a new approach of comprehensive analysis of thalassemia alleles based on third-generation sequencing (TGS) for identification of [alpha]- and [beta]-globin gene variants. Design.--Enrolled in this study were 70 suspected carriers of rare thalassemia variants. Routine gap-polymerase chain reaction and DNA sequencing were used to detect rare thalassemia variants, and TGS technology was performed to identify [alpha]- and [beta]-globin gene variants. Results.--Twenty-three cases that carried rare variants in [alpha]- and [beta]-globin genes were identified by the routine detection methods. TGS technology yielded a 7.14% (5 of 70) increment of rare [alpha]- and [beta]-globin gene variants as compared with the routine methods. Among them, the rare deletional genotype of-THAI was the most common variant. In addition, rare variants of CD15 (G>A) (HBA2:c.46G>A), CD117/118(+TCA) (HBA1:c.354_355insTCA), and [beta]-thalassemia 3.5-kilobase gene deletion were first identified in Fujian Province, China; to the best of our knowledge, this is the second report in the Chinese population. Moreover, HBA1:c.-24C>G, IVS-II-55 (G>T) (HBA1:c.300+55G>T) and hemoglobin (Hb) Maranon (HBA2:c.94A>G) were first identified in the Chinese population. We also identified rare Hb variants of HbC, HbG-Honolulu, Hb Miyashiro, and HbG-Coushatta in this study. Conclusions.--TGS technology can effectively and accurately detect deletional and nondeletional thalassemia variants simultaneously in one experiment. Our study also demonstrated the application value of TGS-based comprehensive analysis of thalassemia alleles in the detection of rare thalassemia gene variants. doi: 10.5858/arpa.2021-0510-OA, Thalassemia is a common inherited blood disorder resulting from deficient synthesis of globin chains. (1) According to the deficiency of globin genes, thalassemia can be classified into [alpha], [beta], [delta], [...]

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. [ABSTRACT FROM AUTHOR]

Background: Congenital hemidysplasia with ichthyosiform nevus and limb defects (CHILD) syndrome is a rare X‐linked dominant, lethal male disorder caused by mutations to the NSDHL (NAD(P)H steroid dehydrogenase‐like protein) gene. It primarily exhibits strictly unilateral congenital hemidysplasia with ichthyosiform erythroderma and ipsilateral limb defects in female individuals. Methods: A Chinese couple suffering from recurrent spontaneous abortion in male fetuses was enrolled in this study. Chromosomal microarray analysis and whole‐exome sequencing were performed for genetic etiological diagnosis. Results: A 33‐year‐old pregnant woman with recurrent spontaneous abortion was experiencing her third pregnancy with a male embryo. In this pregnancy, a miscarriage occurred at a gestational age of 10+6 weeks with no copy number variants. However, a novel mutation c.790‐6C>T in the NSDHL gene was observed in the fetus through whole‐exome sequencing (WES). Parental verification indicated that the NSDHL gene variant was inherited from the mother. Additionally, the variant in the NSDHL gene was absent in her subsequent pregnancy with a female fetus. Conclusion: In this study, we detected c.790‐6C>T, a novel variant in the NSDHL gene that results in recurrent miscarriage in males. Our study may broaden the scope of research on the NSDHL gene in CHILD syndrome and strengthens the application value of WES for the genetic etiological identification of recurrent miscarriage. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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.

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.

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.

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.

Aims: Thalassemia is one of the most prevalent inherited disorders in south China. However, there still has no comprehensive research on molecular characterisation of α-thalassemia and β-thalassemia in the Quanzhou region of Fujian province, a city with high incidence of thalassemia in Southeast China., Methods: A total of 11 668 cases were collected in Quanzhou region from January 2013 to June 2019. The deletions of α-thalassemia were detected by Gap-PCR, α-thalassemia and β-thalassemia mutations were detected by DNA reverse dot blot hybridisation. Rare thalassemia gene testing and DNA sequencing were performed to detect rare and novel thalassemia mutation for suspected rare thalassemia carriers., Results: Among 11 668 subjects, 4796 (41.10%) subjects were diagnosed with thalassemia. 3298 (28.27%) subjects were α-thalassemia carriers, 26 types of α-thalassemia mutations were identified, with the common α-thalassemia genotypes being -- SEA /αα (71.47%), -α 3.7 /αα (17.13%) and -α 4.2 /αα (3.49%). 1407 (12.06%) subjects were β-thalassemia carriers, 18 types of β-thalassemia mutations were identified. The common five genotypes of β-thalassemia were β IVS-II-654 /β N (36.53%), β CD41-42 /β N (30.28%), β CD17 /β N (17.13%), β CD26 /β N (5.12%) and β -28 /β N (4.62%). Additionally, 91 (0.78%) subjects with composite α-thalassemia and β-thalassemia were identified. Furthermore, 9 α-thalassemia and β-thalassemia gene mutations (CAP +40-43 (-AAAC), IVS-I-1 (G>T), IVS-I-5 (G>C), SEA-HPFH, CD53 (-T), CD37 (A>G), -90 (C>T), CD3 (T>C), -α 6.9 ) were identified for the first time in the region. Among them, CD53 (-T), CD37 (A>G) and -90 (C>T) mutations were identified for the first time in Fujian province. Moreover, CD3 (T>C), -α 6.9 mutations were first identified in Chinese individual., Conclusions: Quanzhou region of South China has high incidence of thalassemia mutations. In this study, several cases of rare thalassemia mutations have been identified, providing reference for clinical consultation. The completion of this study is of great significance to strengthen the prevention and control of thalassaemia in the Quanzhou region., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

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.

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: -α 6.9 /-- 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.

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.