[Application of Array-based Comparative Genomic Hybridization in Diagnostic Assessment of Abnormal Prenatal Serological Screening Results of Down's Syndrome].

OBJECTIVE: To explore the application of array-based comparative genomic hybridization (a-CGH) technology in the prenatal diagnostic assessment of abnormal serological prenatal screening results of Down's syndrome (DS). METHODS: A total of 3 578 amniotic fluid samples from pregnant women who underwent amniocentesis for prenatal diagnosis solely due to abnormal serological prenatal screening results were selected. The samples were categorized into 3 groups, 2 624 in the high-risk group, 662 in the borderline-risk group, and 292 in the abnormal multiple of median (MoM) group. a-CGH was performed on the Agilent CGX ™ (8×60K) platform and the data were analyzed by the Genoglyphix ® software. RESULTS: The overall detection rate of chromosomal abnormalities was 3.38% (121/3 578). Among the chromosomal abnormalities, 49.59% (60/121) was aneuploidies, 42.15% (51/121) was pathogenic copy number variants (pCNVs), and 8.26% (10/121) was likely pathogenic CNVs (lpCNVs). The detection rate of copy number variant of uncertain significance (VUS) was 1.03% (37/3 578). In the high-risk, the borderline-risk and the abnormal MoM groups, the detection rate of chromosomal abnormalities was 3.54% (93/2 624), 2.87% (19/662) and 3.08% (9/292), respectively; the detection rate of p/lp CNVs was 1.64% (43/2 624), 1.81% (12/662) and 2.05% (6/292), respectively; the detection rate of trisomy 21 and trisomy 18 was 1.37% (36/2 624), 0.76% (5/662) and 0.34% (1/292) in the three groups, respectively. There were no significant differences in all the detection rate among these groups ( P>0.05). One sample with X(51)/XYY(49) confirmed by fluorescence in situ hybridization (FISH) was misdiagnosed by a-CGH. CONCLUSION: Prenatal diagnosis with a-CGH is of great significance for reducing birth defects in pregnancies with abnormal serological prenatal screening results of DS. It can also be used to detect CNVs of microdeletion/microduplication syndromes.

[Application of Array-based Comparative Genomic Hybridization in the Prenatal Diagnosis of Fetal Chromosomal Aberration in Gravidas with Advanced Age].

OBJECTIVE: To evaluate the clinical application of array-based comparative genomic hybridization (a-CGH) in the prenatal diagnosis of fetal chromosomal aberrations in gravidas with advanced maternal age (AMA). METHODS: A total of 3 677 amniotic fluid samples from pregnant women who underwent amniocentesis for prenatal diagnosis solely due to AMA were selected. Array-CGH was performed on the Agilent CGX TM (8X60K) platform and the data were analyzed by the Genoglyphix software. RESULTS: The overall detection rate of chromosomal aberration was 2.04% (75/3677), with 53.33% (40/75) being aneuploidies, including 22 cases of trisomy-21, 5 cases of trisomy-18, 8 cases with XXY, 3 cases of XYY and 2 cases of mosaic monosomy X, 32.00% (24/75) being pathogenic copy number variations (pCNVs), including 19 cases of microdeletion and 5 cases of microduplication, with the fragment size ranging from 323 kb to 26 780 kb, and 14.67% (11/75) being likely pathogenic CNVs (lpCNVs), including 7 cases of microdeletion and 7 cases of microduplication, with the fragment size ranging from 358 kb to 16 873 kb. Besides, the detection rate of CNVs of unknown clinical significance (VUS) was 0.84% (31/3 677). The detection rate of aneuploidies increased significantly with increased maternal age ( P<0.05). However, there were no significant differences in the detection rate of p/lpCNVs among different maternal age groups ( P>0.05). CONCLUSION: Our findings suggest that, compared with traditional karyotype analysis, a-CGH not only detects aneuploidies, but also detect pathogenic CNVs, including microdeletion/microduplication syndromes. The detection rate of fetal aneuploidies was closely correlated to maternal age. However, no correlation was found between the detection rate of p/lpCNVs and maternal age.

[Clinical Application Assessment of KaryoLite BoBs Combined with QF-PCR in the Detection of Products of Conception].

OBJECTIVE: To assess the accuracy and discuss the feasibility of KaryoLite bacterial artificial chromosome on beads (KL-BoBs) and quantitative fluorescent polymerase chain reaction (QF-PCR) in genetic testing of products of conception (POC) by comparing with the chromosomal microarray analysis (CMA) test results. METHODS: Eighty-one cases of abortion samples were collected in the prenatal diagnosis center of West China Second University Hospital in Sichuan University from May to August 2016,including 61 cases of placenta tissues,19 cases of fetal muscle tissues and 1 case of fetal liver tissue. KL-BoBs and QF-PCR were used to detect the samples. The results were compared with those of CMA test to evaluate the accuracy of KL-BoBs and QF-PCR. RESULTS: Of the 81 POC samples,the results of 70 samples tested by KL-BoBs was consistent with that of CMA. Among them,36 cases were normal karyotype and 34 cases were abnormal karyotypes (aneuploidy). Triploid could not been detected by KL-BoBs (the results were shown 2 cases were normal karyotype and 5 cases were aneuploidy),whereas CMA and QF-PCR could be detected. Copy number variation of small segments could not been detected by KL-Bobs. Four cases of copy number variationwere detected by CMA.Compared with CMA,the positive coincident rate of KL-BoBs combined with QF-PCR was 91.1% (41/45),the negative coincidence rate was 100% (36/36). The accuracy rate of KL-BoBs was 86.4% (70/81),the false positive was 0% and the false negative was 13.3% (6/45). Whereas both KL-BoBs and QF-PCR were simultaneously detected,the accuracy rate would be improved to 95.1% (77/81). CONCLUSION: The accuracy rate of KL-BoBs combined with QF-PCR was high for testing early pregnancy abortion tissue. It can be used as a first-tier test.

Two novel variants of the PHEX gene in patients with X­linked dominant hypophosphatemic rickets and prenatal diagnosis for fetuses in these families.

X­linked hypophosphatemic rickets (XLHR; OMIM 307800) is an X­linked dominant disorder caused by mutations in the phosphate­regulating neutral endopeptidase homolog X­linked (PHEX) gene, which is located at Xp22.11. In the present study, two novel variants of the PHEX gene were identified in two unrelated families with XLHR by directly sequencing all 22 exon regions and intron/exon boundaries of the PHEX gene. One missense variant, NM_000444.5: c.1721T>A, was identified in exon 17 of the PHEX gene in Family 1, which led to an amino acid change in the p.Ile574Lys protein. The other splicing variant identified was NM_000444.5: c.591A>G, in exon 5 in Family 2, resulting in a deletion of 77 bp in the 3' site of exon 5 during splicing, which was verified by direct cDNA sequencing of the PHEX gene. According to the results of reverse transcription­quantitative polymerase chain reaction analysis, the affected male with the splicing variant c.591A>G showed normal gene expression of PHEX, whereas the affected female exhibited low gene expression, compared with normal females. Based on these findings, prenatal diagnoses were made for the fetuses with a family history of XLHR using the backup amniotic fluid samples. One fetus without the missense variant was confirmed to be a healthy girl in a follow­up visit 1 month following birth.

[The assessment of reliability and validity of musculoskeletal questionnaire].

OBJECTIVE: To evaluate the reliability and validity of musculoskeletal questionnaire. METHODS: A self-administered modified musculoskeletal questionnaire was used to investigate 12 098 workers from eight occupations, i.e. coal mining, petroleum, metallurgical, mechanical manufacturing, chemical, garment and railroad transportation industries and education. The Cronbach's α coefficient, analysis of covariance and multiple logistic regression were used to assess the reliability and validity of musculoskeletal questionnaire. RESULTS: The consistent test between total items of Musculoskeletal Questionnaire and each factor showed that the range of Cronbach's α was 0.52 ∼ 0.92, except from vibration factor, other Cronbach's α was more than 0.7. All 55 items of Musculoskeletal Questionnaire were subjected to factor analysis, and ten latent factors were identified, which explained 55.17% of the total variance. The potentially hazardous working conditions could be categorized into seven dimensions (force, dynamic load, static load, repetitive load, climate factors, vibration exposure and environmental ergonomic factor), which consisted with the theory model. The results of covariance analysis indicated that there were significant difference among 7 dimension indices in different jobs (P < 0.01). CONCLUSION: The modified Musculoskeletal Questionnaire is a valid and reliable tool for measuring musculoskeletal workload.