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.

Comprehensive analysis of early pregnancy loss based on cytogenetic findings from a tertiary referral center.

BACKGROUND: Pregnancy loss is one of the most common complications during pregnancy. Clinical consultation based on etiology analysis are critical for reducing anxiety and distress. This study aimed to perform a comprehensive analysis for products of conception (POC) in miscarriage based on genetic etiology and clinical information. METHODS: A retrospective study was conducted according to cytogenetic findings of 1252 POC from spontaneous pregnancy loss over 11 years. The frequencies and profiles of chromosomal abnormalities were discussed according to the classification of women with different maternal ages, previous miscarriage history, normal live birth history, and different modes of conception. RESULTS: A total of 667 (53.2%) chromosomal abnormalities were observed, including 592 (47.3%) cases of numerical abnormalities, 38 (3.0%) cases of structural abnormalities, and 37 (3.0%) cases of mosaic aberrations. In women above 40 years of age, the rates of chromosomal abnormalities and viable autosomal trisomy were significantly higher than those in women with ≤ 29, 30-34, and 35-39 years of age (p < 0.05). The frequency of abnormal karyotype in women with normal live birth history was 61.1%, significantly higher than 52.5% in women without normal live birth history (p < 0.05). There was no significant differences among women without, with 1-2, and ≥ 3 previous miscarriages regarding the rate of abnormal karyotype (p > 0.05); viable autosomal trisomy was less common in women with ≥ 3 previous miscarriages than women with < 3 miscarriages. The frequency of chromosomal abnormalities was 49.0% and 55.0% in women with assisted conception and natural conception (p > 0.05), respectively; monosomy X was more frequently detected in women with natural conception than assisted conception. CONCLUSION: The frequencies and profiles of chromosomal abnormalities in early miscarriages are strongly associated with clinical information including maternal age, previous miscarriage, live birth history, and mode of conception. Cytogenetic analysis of POC should be recommended to women with a first miscarriage and women with normal live birth history.

Chromosomal microarray analysis for pregnancies with abnormal maternal serum screening who undergo invasive prenatal testing.

Recently, chromosomal microarray analysis (CMA) has been implemented as a first-tier test in pregnancies with ultrasound anomalies. However, its application for pregnancies with abnormal maternal serum screening (AMSS) only is not widespread. This study evaluated the value of CMA compared to traditional karyotyping in pregnancies with increased risk following first- or second-trimester maternal serum screening. Data from 3973 pregnancies with referral for invasive prenatal testing following AMSS were obtained from April 2016 to May 2020. Routine karyotyping was performed and single nucleotide polymorphism array was recommended. The foetuses were categorized according to the indications as AMSS only (group A) and AMSS with ultrasound anomalies (group B). CMA was performed on 713 prenatal samples. The proportion of women opting for CMA testing in both groups increased over the years. The incremental yield of clinically significant findings for pregnancies with high risk of screening results was similar to that for the foetuses with ultrasound soft markers (P > 0.05), but significantly lower than that for the foetuses with structural anomalies (P < 0.05). The total frequencies of variants of unknown significance in groups A and B showed no significant difference (P > 0.05). CMA should be performed for pregnant women undergoing prenatal invasive testing due to AMSS, especially with high-risk results, regardless of ultrasound findings.

Comparison of three lymph node staging systems in evaluating the prognosis of patients with pT3 esophageal squamous cell carcinoma.

To explore the prognostic value of three lymph node staging systems, including number of positive lymph nodes (pN), lymph node ratio (LNR), and log odds of positive lymph nodes (LODDS), in patients with pT3 stage esophageal squamous cell carcinoma (ESCC). Data from 1667 patients with pT3 stage ESCC who underwent surgical resection were reviewed. The log-rank test was used to assess the differences in overall survival (OS) between groups. Multivariate analysis was performed to identify independent prognostic factors. The receiver operating characteristic curve was used to assess the prognostic accuracy of the three staging methods. The median survival time for the entire group was 48.0 months, and the 1-, 3- and 5-year OS rates were 83.9%, 55.1% and 66.6%, respectively. All three lymph node staging systems were significantly correlated with OS in univariate and multivariate analyses. However, LNR and LODDS staging systems could more accurately predict survival than the pN staging system in patients with < 15 lymph nodes dissected, while LODDS have the best prognostic homogeneity. All three staging systems could be used for prognostic assessment in pT3 stage ESCC. But LODDS staging system might be superior to the others due to its prognostic homogeneity.

[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.

Optimization of regional median equations of prenatal screening markers for trisomy 21 in a Chinese population.

To establish gestational age-specific and body weight-specific mid-trimester normal median equations for the prenatal serum markers α-fetoprotein (AFP), free ß subunit human chorionic gonadotropin (fßHCG), and unconjugated oestriol (uE3) for a Chinese population; to compare and replace the median equations built in LifeCycle software; to evaluate the effect of equations used for gestation correction on estimating risk in Down's syndrome, Edward's syndrome, and neural tube defect (NTD).A total of 353,065 cases of prenatal screening data of pregnant women were screened by 13 prenatal screening institutions in China. The local median equations of each institution and the large data were fitted by the least square regression, and then the difference was compared between large data equations and local median equations. The applicability of the localized median equations was evaluated by the determination coefficient. Based on the established median equations, multiples of median (MoM) of each values were calculated and compared with the latest Down's syndrome quality assurance support service (DQASS).There is no significant difference between the local median equations of each institution and the large sample median equations, which are various from LifeCycle built-in median equations. Besides, the determination coefficient of localized median equations are >0.99. 97.0% MoM medians obtained by using local median equations are consistent with latest standard of DQASS.The median established by large sample data represents the median level of a Chinese population, and can be used to replace the software built-in median equations to achieve better screening results.

[Gene Diagnosis and Analysis of Clinical Hematological Phenotype of Thailand Deleted α-Thalassemia 1].

OBJECTIVE: To investigate the hematologic characteristics and gene diagnosis of patients with Thailand deleted α-thalassemia 1, so as to provide the information for clinical genetic counseling. METHODS: The clinical data of 32 patients with Thailand delated α-thalassemia 1 were analyzed retrospectively; the hematologic characteristics and gene diagnosis of Thailand deleted type were investigated by using routine hematologic examination, genetic detection of common thalassemia and Thailand deleted α-thalassemia 1. RESULTS: Among 32 cases, the Thailand deleted α-thalassemia 1 heterozygote was found in 29 cases, the Thailand deleted α-thalassemia 1 and α(3.7) gene deletion double heterozygote were found in 1 case, the Thailand deleted α-thalassemia 1 with ß-thalassemia (1 case with codons 41-42 mutation heterozygous, 1 case with CD17 mutation heterozygous) was found in 2 cases by detection. The MCV and MCH levels were decreased in all cases of Thailand deleted thalassemia 1, there were significant differences in RBC, MCV, MCH (P<0.05) between normal control and Thailand deletion α-thalassemia 1 group; there were also significant differences in MCHC (P<0.05) between Southeast asia thalassemia and Thailand deleted α-thalassemia 1 group. CONCLUSION: There are no significant differences in hematological parameters except MCHC between Southeast asia thalassemia and Thailand deleted α-thalassemia 1 group. moreover the Thailand deleted α-thalassemia 1 in a certain proportion exists in area with high incidence of thalassemia, therefor the clinicians should pay more attention to the screen and diagnosis of Thailand delated α-thalassemia and can exactly diagnose the Thailand delected α-thalassemia 1 on the basis of comprehensive analysis of conventional and Thailand delected α-thalassemia 1 detection results, clinical presentation, hematologic parameters and ultrasonic examination, so as to avoid the birth of child with severe and intermidiate type α-thalassemia caused by Thailand deleted α-thalassemia 1.

[Molecular epidemiological analysis of α- and ß-thalassemia in Fujian province].

OBJECTIVE: To investigate the gene prevalence and spectrum of alpha- and beta-thalassemia in Fujian province. METHODS: A total of 11 234 of neonatal cord blood samples were collected for a prevalence study of alpha- and beta-thalassemia. All subjects included in this study were registered in 9 cities of Fujian province. A complete blood count and high performance liquid chromatography (HPLC) were performed in all samples, with microcytosis (MCV≤ 79 f1 and MCH≤ 27 pg) or HPLC positive cases further studied by DNA analysis. alpha- and beta-thalassemia were determined by using gap-PCR and reverse dot blot (RDB) assays. Unknown positive samples were analyzed directly with DNA sequencing. RESULTS: Of all 11 234 cord blood samples, 356 were identified as from alpha-thalassemia gene carriers, 7 deletion genotypes were identified including 236 (--SEA/ α α) cases, 67 (α 3.7/ α α) cases, 24 (alpha 4.2/alpha alpha) cases, 3 (alpha 3.7/ SEA) cases, 1 (alpha 4.2/ SEA) cases, 1 (alpha 3.7/ alpha 3.7) cases, 1 (alpha 3.7/ alpha 4.2) cases; 3 non-deletion genotypes were detected, including 7 (alpha alpha QS/ alpha alpha) cases, 3 (α α CS/α α) cases, 2 (α α WS/ α α) cases, the most common mutation was SEA/α α, which accounted for 66.29%, 148 individuals were found to have beta-hemoglobin gene mutations. 12 different mutations were identified, namely 65 IVS-2 654 (C>T) cases, 40 CD41-42(-TCTT, 12 CD17(A>T) cases, 10 -28(A>G) cases,7 CD27-28(+C) cases, 5 start codon ATG>AGG cases, 2 CD26(G>A) cases, 1 CD71-72(+A) cases, 1 IVS-1-1(G>T) cases, 1 CD43(G>T) cases, 2 -29(A>G) cases, 2 Codon 36 (-C) cases, the most common mutation was IVS-2 654(C>T) and CD41-42(-TCTT), which accounted for 70.95%. A novel beta-globin gene mutation CD36 (-C) allele was also detected. The carrier rate of thalassemia in Fujian population is 4.41%. In addition, 9 beta-thalassemia carriers were found with alpha-thalassemia mutation. CONCLUSION: The research has revealed the type of gene mutations in alpha- and beta-talassemia in Fujian province. The beta-thalassemia mutations in Fujian province are complex, which were also obviously heterogeneous. This will significant value for screening the incidence, provide the valuable information for genetic counseling and prenatal diagnosis.

Molecular spectrum of ß-thalassemia in Fujian Province, Southeastern China.

To provide basic information for ß-thalassemia (ß-thal) screening, genetic counseling and prenatal diagnosis (PND), we characterized ß-thal mutations in Fujian Province, Southeastern China. A total of 16 different ß-thal gene mutations were identified from 1058 patients. Of these, the IVS-II-654 (C>T) and codons 41/42 (-TCTT) were the most prevalent, accounting for 76.3% of the total mutations. Six gene mutations, IVS-I-1 (G>T), Cap +40 to +43 (-AAAC), codon 30 (A>G), +22 (G>A), codons 54-58 (-TTATGGGCAACCC) and the initiation codon (ATG>AGG) were characterized for the first time in the Fujian population. Furthermore, the following mutations, +22 (G >A), codon 36 (-C) and codon 30 (A>G), were identified for the first time in Chinese individuals. This was the first comprehensive mutation spectrum of ß-thal mutations studied in Fujian Province, People's Republic of China (PRC).