Fetal DNA in maternal plasma and serum has been shown to be a useful material for fetal gender determination and for screening tests for abnormal pregnancies except during early gestational ages. Maternal serum samples were obtained from 81 pregnant women during the 5th-10th weeks of gestation. Fetal gender was determined by conventional polymerase chain reaction (PCR) to detect a Y-chromosomal sequence (DYS14) in maternal serum during early gestation and confirmed by examination of the newborns after delivery. Real-time quantitative analyses of the SRY and beta-globin genes were also performed in order to determine fetal gender and to quantify fetal DNA concentration in maternal serum during early gestation. When using conventional PCR, the total sensitivity of identifying a male fetus was 95%, but its sensitivity after the 7th week was 100%, whereas in real-time quantitative PCR, the total sensitivity after the 5th week was 100%. Quantitative analyses of the SRY gene revealed that the mean concentration of fetal DNA in maternal serum was 30.55 copies/ml, that fetal DNA concentration showed a tendency to increase with the progression of pregnancy, and that it had a wide normal range. Thus, we could confidently determine fetal gender by using maternal serum samples taken as early as the 7th week.

Fluorescence in situ hybridization (FISH) with single-color chromosome-specific probes was used to study the rates of disomy for chromosome 1, 16, X, and Y in sperm of fertile and infertile subjects. Diploidy rates were studied using a two-color cocktail of probes for chromosomes 17 and 18 in the same sperm samples. Two-color methodology was not available at the outset of the study. A total of 450,580 spermatozoa were studied from 21 subjects (9 fertile, 12 infertile). Significant differences were observed in the disomy rates between chromosomes with the highest frequency observed for chromosome 16 (0.17%) and the lowest for the Y chromosome (0.10%). No differences were observed between fertile and infertile subjects for either diploidy or disomy. Total disomy rates for chromosomes 1, 16, X and Y ranged from 0.34% to 0.84% among infertile subjects, and 0.32% to 0.61% among fertile subjects. Our data suggest that generalized aneuploidy in sperm is not a major contributor to unexplained infertility.

Aim The purpose of this study was to report the 3‐year experience of a nationwide demonstration project to introduce non‐invasive prenatal testing (NIPT) of maternal plasma for aneuploidy, and review the current status of NIPT in Japan. Methods Tests were conducted to detect aneuploidy in high‐risk pregnant women, and adequate genetic counseling was provided. The clinical data, test results, and pregnancy outcomes were recorded. We discuss the problems of NIPT on the basis of published reports and meta‐analyses. Results From April 2013 to March 2016, 30 613 tests were conducted at 55 medical sites participating in a multicenter clinical study. Among the 30 613 women tested, 554 were positive (1.81%) and 30 021 were negative (98.1%) for aneuploidy. Of the 289, 128, and 44 women who tested positive for trisomies 21, 18, and 13, respectively, and underwent definitive testing, 279 (96.5%), 106 (82.8%), and 28 (63.6%) were determined to have a true‐positive result. For the 13 481 women with negative result and whose progress could be traced, two had a false‐negative result (0.02%). The tests were performed on the condition that a standard level of genetic counseling be provided at hospitals. Conclusion Here, we report on the 3‐year nationwide experience with NIPT in Japan. It is important to establish a genetic counseling system to enable women to make informed decisions regarding prenatal testing. Moreover, a welfare system is warranted to support women who decide to give birth to and raise children with chromosomal diseases.

Frequencies of disomy and diploidy in spermatozoa for chromosomes X, Y and 18 were compared among severe oligozoospermic men (<5x10(6) spermatozoa/ml), oligozoospermic men (5-20x10(6) spermatozoa/ml), and normospermic men using three-colour fluorescence in-situ hybridization (FISH). Semen samples were collected from 10 severe oligozoospermic men aged 26-49 years, 10 oligozoospermic men aged 27-48 years and seven normospermic men aged 25-31 years. Karyotypes in lymphocytes obtained from peripheral blood were all 46,XY. In severe oligozoospermic men, analysis of 200 interphases per individual using FISH showed XY constitutions for sex chromosomes in all cells. A minimum of 10 000 sperm nuclei per individual for each chromosome was evaluated in severe oligozoospermic men and oligozoospermic men, and a minimum of 6000 sperm nuclei per individual in normospermic men. In total, 245 707 sperm nuclei were evaluated. The hybridization efficiency was 99.8%. The severe oligozoospermic men showed significantly higher frequencies of XY disomy (0.41%) and diploidy (0.49%) compared with oligozoospermic men (0.16%, P < 0.01; 0.22%, P < 0.05) and normospermic men (0.18%, P < 0.05; 0.21%, P < 0.05) (Mann-Whitney U-test). The data suggest that when severe oligozoospermic men undergo intracytoplasmic sperm injection, there can be an increase in the rate of conceptuses with 47,XXY chromosomes.

Recently, intracytoplasmic sperm injection (ICSI) has been extremely successful for the treatment of male infertility. However, transmission of cytogenetic defects to offspring is a great concern. There are two types of cytogenetic problems in patients seeking ICSI; one is the transmission of genetic defects from patients with constitutional chromosomal abnormalities and the second is the generation of de novo defects in infertile men. Generally about 5.1% of infertile men have chromosomal abnormalities. Among such infertile men, men with severe spermatogenesis defects, including oligozoospermia and azoospermia, are subjects for ICSI. Therefore it is very important to obtain cytogenetic information in these infertile patients. Furthermore, oligozoospermic men with a normal somatic karyotype also have increased frequencies of sperm chromosome abnormalities. Oligozoospermia is usually associated with other sperm alterations, for example oligoasthenozoospermia, oligoteratozoospemia and oligoasthenoteratozoospermia. In this review, the relationship between sperm concentration and sperm aneuploidy frequencies has been analyzed. The inverse correlation between the frequency of sperm aneuploidy and concentration has been reported in extensive studies. Especially in severe oligozoospermia, a significantly higher frequency of sex chromosome aneuploidy has been observed and this has been corroborated in recent clinical outcome data of ICSI.