An Open Dataset of Annotated Metaphase Cell Images for Chromosome Identification.

Chromosomes are a principal target of clinical cytogenetic studies. While chromosomal analysis is an integral part of prenatal care, the conventional manual identification of chromosomes in images is time-consuming and costly. This study developed a chromosome detector that uses deep learning and that achieved an accuracy of 98.88% in chromosomal identification. Specifically, we compiled and made available a large and publicly accessible database containing chromosome images and annotations for training chromosome detectors. The database contains five thousand 24 chromosome class annotations and 2,000 single chromosome annotations. This database also contains examples of chromosome variations. Our database provides a reference for researchers in this field and may help expedite the development of clinical applications.

Prenatal diagnosis of extrastructurally abnormal chromosomes: clinical experience and literature review.

BACKGROUND: To evaluate the clinical association of extrastructurally abnormal chromosomes (ESACs) with pregnancy outcome based on the cytogenetic characteristics of the ESACs. METHODS: We retrospectively reviewed 12 ESAC cases identified from 12,991 cases who received genetic amniocentesis between January 1983 and March 2008. Prenatal ultrasound findings, characteristics of ESACs (karyotypes, special features, origin, inheritance) and pregnancy outcomes were recorded. RESULTS: The prenatal prevalence of ESACs was 0.092% (12/12,991). Of the 12 ESAC cases, all were de novo. Seven (58.3%) originated from nonacrocentric chromosomes and the other 5 (41.7%) were from acrocentric chromosomes, with 3 originating from chromosome 15. Six of the 12 cases (50%) were large ESACs; however, the other 6 (50%) were medium to small ESACs. All acrocentric ESACs contained dicentric and bisatellite characteristics. Using FISH and SKY techniques, the origins of 2 cases (patients 10 and 12) were clearly identified to be from chromosomes 15 and 10, respectively. Five of the 12 ESAC cases (41.7%) had congenital anomalies found by prenatal ultrasound. All were nonacrocentric in origin that were medium (1/5) to large (4/5) in size. After prenatal genetic counseling, 8 of the 12 (66.7%) couples opted to terminate the pregnancy. The other 4 (33.3%) continued the pregnancy and their babies were delivered at term normally and were followed-up, with normal development ranging from 2 to 17 years. CONCLUSION: With sophisticated cytogenetic characterization and ultrasound examination, it is possible to precisely categorize most fetuses with ESACs as being either at high risk of abnormality or at a relatively low risk.

Detection of chromosome aberrations in the second trimester using genetic amniocentesis: experience during 1995-2004.

OBJECTIVE: To retrospectively investigate the 10-year experience of prenatal diagnosis of fetal chromosome aberrations by second-trimester amniocentesis. METHODS: Data were collected at Taichung Veterans General Hospital between 1995 and 2004 from cytogenetic analyses of cultured amniocytes from second-trimester amniocentesis. The main indications for amniocentesis included advanced maternal age, abnormal maternal serum screening results, and abnormal ultrasound findings. Chromosome aberrations included autosomal aneuploidies, sex chromosome aneuploidies, polyploidies, and rearrangements. Variant chromosomes were considered to be normal and excluded. RESULTS: A total of 7,028 amniocenteses were performed and analyzed for chromosome aberrations. Among these, 4,026 (57.29%) were for advanced maternal age, 1,500 (21.34%) for abnormal maternal serum screening results, 553 (7.87%) for abnormal ultrasound findings, and 949 (13.50%) for other reasons. The highest detection rate of chromosome aberrations was in cases undergoing amniocentesis for abnormal ultrasound findings (8.86%), followed by other reasons (2.74%), abnormal maternal serum screening results (2.60%), and advanced maternal age (2.31%). Chromosome aberrations were detected in 207 cases (2.90%), including fetuses of 93 older mothers, 39 mothers with abnormal serum screening results, 49 mothers with abnormal ultrasound findings, and 26 mothers with other reasons for amniocentesis. Of fetuses with chromosome aberrations, 144 (69.56%) had trisomy 13, trisomy 18, trisomy 21, or sex chromosome disorder. The other 63 cases (30.44%) included balanced translocation, unbalanced abnormality, inversion, and marker chromosome. CONCLUSION: For daily practice, our data could offer a database for proper genetic counseling, such as termination issues and future pregnancies.