BackgroundIsodicentric chromosomes are the most frequent structural aberrations of human Y chromosome, and usually present in mosaicism with a 45, X cell line. Several cytogenetic techniques have been used for diagnosing of uncommon abnormal sex chromosome abnormalities in prenatal cases.Case presentationA 26-year-old healthy woman was referred to our centre at 24 weeks of gestation age. Ultrasound examination indicated she was pregnant with imbalanced development of twins. Amniocentesis was referred to the patient for further genetic analyses. Quantitative Fluorescent Polymerase Chain Reaction (QF-PCR) indicated the existence of an extra Y chromosome or a structurally abnormal Y chromosome in primary amniotic cells. Chromosome microarray (CMA) analysis based on Comparative Genomic Hybridization (aCGH) platform was performed and identified a 10.1 Mb deletion on Y chromosome in 8-days cultured amniotic cells. Combined with the data of QF-PCR and aCGH, karyotyping and fluorescence in situ hybridization (FISH) revealed a mosaic cell line of 45,X[27]/46,X, idic(Y)(q11.22) [14] in fetus.The karyotyping analysis of cord blood sample was consistent with amniotic cells. The parental karyotypes were normal, which indicated this mosaic case of isodicentric Y (idicY) chromosomes of the fetus was a de novo case.ConclusionSeveral approaches have been used for the detection of numerical and structural chromosomal alterations of on prenatal cases. Our report supported the essential role of incorporating multiple genetic techniques in prenatal diagnosing and genetic counseling of potential complex sex chromosomal rearrangements.

No abstract

Background:In medicine, karyotyping chromosomes is important for medical diagnostics, drug development, and biomedical research. Unfortunately, chromosome karyotyping is usually done by skilled cytologists manually, which requires experience, domain expertise, and considerable manual efforts. Therefore, automating the karyotyping process is a significant and meaningful task. Method:This paper focuses on chromosome classification because it is critical for chromosome karyotyping.In recent years, deep learning-based methods are the most promising methods for solving the tasks of chromosome classification. Although the deep learning-based Inception architecture has yielded state-of-the-art performance in the 2015 ILSVRC challenge, it has not been used in chromosome classification tasks so far. Therefore, we develop an automatic chromosome classification approach named CIR-Net based on Inception-ResNet which is an optimized version of Inception. However, the classification performance of origin Inception-ResNet on the insufficient chromosome dataset still has a lot of capacity for improvement. Further, we propose a simple but effective augmentation method called CDA for improving the performance of CIR-Net. Results:The experimental results show that our proposed method achieves 95.98% classification accuracy on the clinical G-band chromosome dataset whose training dataset is insufficient.Moreover, the proposed augmentation method CDA improves more than 8.5% (from 87.46% to 95.98%) classification accuracy comparing to other methods.In this paper, the experimental results demonstrate that our proposed method is recent the most effective solution for solving clinical chromosome classification problems in chromosome auto-karyotyping on the condition of the insufficient training dataset.

Objective We present a prenatal case of 45,X/46,dic(X) with two asymmetric chromosome arms. Methods Single nucleotide polymorphism array(SNP-array),fluorescence in situ hybridization(FISH) and conventional cytogenetic analysis were performed for verification. Results The conventional G-banding analysis revealed a mosaic karyotype of mos 45,X/46,X,dic (X;X) (p11.2;q10) and the C-banding analysis showed that the derivative X chromosome had two darkly stained bands near the centromere.Two green signals and single green signal (X chromosome cetromere) were observed simultaneously in the metaphases and interphases FISH confirmation test,which indicated a mosaicism for X chromosome in the uncultured amniocytes.The SNP-array results revealed two copy-number-loss on the X chromosome.One was a 54.3Mb deletion in Xp22.33-p11.22 including 414 genes.Another was a mosaic deletion in Xp11.22-q28. Conclusion A combination of molecular and cytogenetic techniques should be employed to provide adequate genetic counseling to mosaic Turner sydrome patients for avoiding misdiagnosis.

Background: To investigate the correlation between Y chromosome microdeletion and cytogenetic analysis in patients with azoospermia.Methods: A total of 516 patients with azoospermia were enrolled from March 2015 to December 2019. Karyotype analysis(G-banding) was performed with peripheral blood.Y-chromosome azoospermia factor (AZF) were detected by quantitative fluorescent polymerase chain reaction (QF-PCR).Results: Chromosome abnormality was detected in 66 of the 516 azoospermia patients, with an abnormal rate of 12.8% In addition, 7.8% cases(40/516) presented with Y-chromosome AZF microdeletions, in which 27 cases patients with karyotype of 46,XY(67.5%,27/40) and 13 cases of chromosome abnormalities (32.5%,13/40).Conclusion: The incidence of Y chromosome microdeletion was higher in the patients with karyotype of 46,XY. Conventional cytogenetics cannot directly reflect the microdeletions of Y chromosome. Therefore, the combination of this two detection methods can help to clarify the genetic causes of patients with azoospermia and provide a theoretical basis for clinical assisted reproductive technology.