Equipoise of recent estimated Down syndrome live births in Japan

Chromosomal and cellular therapeutic approaches for Down syndrome: A research update

In individuals with Down syndrome (DS), an additional HSA21 chromosome copy leads to the overexpression of a myriad of HSA21 genes, disrupting the transcription of the entire genome. This dysregulation in transcription and post-transcriptional modifications contributes to abnormal phenotypes across nearly all tissues and organs in DS individuals. The array of severe clinical symptoms associated with trisomy 21 poses a considerable challenge in the quest for a cure for DS. Fortunately, a wealth of research suggests that chromosome therapy, hinging on cutting-edge genome editing technologies, can potentially eliminate the extra copy of the human chromosome 21. Genome editing tools have demonstrated their efficacy in restoring trisomy to a normal diploid state in vitro DS cell models. Furthermore, we delve into the noteworthy findings in cellular therapy for DS, with recent studies showcasing the increasing feasibility of strategies involving stem cells and CAR T-cells to address corresponding clinical phenotypes.

The expressivist argument for recent policy changes regarding the provision of prenatal testing in Japan

The Japanese government and medical professionals have negative attitudes toward the provision of prenatal testing and related information due to social concern regarding discrimination against persons with disabilities. However, with the rapid increase in the number of non-invasive prenatal tests, particularly at non-certificated medical facilities, in response to the growing demand from pregnant women, the Japanese government and medical professional associations have enacted radical changes marking an active commitment to the provision of information on these services. While a major justification for these policy changes is to ensure respect for reproductive autonomy and women's self-determination, they may reinforce the concern regarding discrimination. This article investigated the argument that these new policies may reinforce discrimination and examined three objections to this argument. The results revealed that the recent policy changes, particularly for specific fetal traits, may imply a negative belief about people living with the same traits. Consequently, fundamental institutional changes are necessary.

Maternal Exposure to Per- and Polyfluoroalkyl Substances and Offspring Chromosomal Abnormalities: The Japan Environment and Children's Study

BACKGROUND

Although recent in vitro experimental results have raised the question of whether maternal exposure to per- and polyfluoroalkyl substances (PFAS) may be a potential environmental risk factor for chromosomal abnormalities, epidemiological studies investigating these associations are lacking.

OBJECTIVES

This study examined whether prenatal PFAS exposure is associated with a higher prevalence of chromosomal abnormalities among offspring.

METHODS

We used data from the Japan Environment and Children's Study, a nationwide birth cohort study, and employed logistic regression models to examine the associations between maternal plasma PFAS concentrations in the first trimester and the diagnosis of chromosomal abnormalities in all births (artificial abortions, miscarriages, stillbirths, and live births) up to 2 years of age. In addition, we examined associations with mixtures of PFAS using multipollutant models.

RESULTS

The final sample consisted of 24,724 births with singleton pregnancies, of which 44 confirmed cases of chromosomal abnormalities were identified (prevalence: 17.8/10,000 births). When examined individually, exposure to perfluorononanoic acid (PFNA) and perfluorooctane sulfonic acid (PFOS) showed positive associations with any chromosomal abnormalities with age-adjusted odds ratios of 1.81 (95% CI: 1.26, 2.61) and 2.08 (95% CI: 1.41, 3.07) per doubling in concentration, respectively. These associations remained significant after Bonferroni correction, although they did not reach the adjusted significance threshold in certain sensitivity analyses. Furthermore, the doubling in all PFAS included as a mixture was associated with chromosomal abnormalities, indicating an age-adjusted odds ratio of 2.25 (95% CI: 1.34, 3.80), with PFOS as the predominant contributor, followed by PFNA, perfluoroundecanoic acid (PFUnA), and perfluorooctanoic acid (PFOA).

DISCUSSION

The study findings suggested a potential association between maternal exposure to PFAS, particularly PFOS, and chromosomal abnormalities in offspring. However, the results should be interpreted cautiously, because selection bias arising from the recruitment of women in early pregnancy may explain the associations. https://doi.org/10.1289/EHP13617.

Vocational identity in decision-making for terminating/continuation of pregnancy following non-invasive prenatal testing and hypothetical diagnosis among Japanese university students

The use of prenatal testing in Japan is expected to increase. However, there are ethical concerns regarding pregnancy termination upon the detection of fetal chromosomal abnormalities, such as Down syndrome. Furthermore, factors associated with decision-making following a positive result of Down syndrome after prenatal screening remain unclear. Therefore, we aimed to evaluate the association between decision-making among university students following a hypothetical positive result of Down syndrome in prenatal screening and their perception of their future career development defined as vocational identity. This cross-sectional study included 256 individuals (109 men, 143 women, and four who preferred not to answer). Self-anonymous semi-structured questionnaires were distributed to collect information regarding socio-demographic characteristics, vocational identity, and decision-making following a positive prenatal screening result of Down syndrome. Vocational identity was assessed using the Vocational Identity Measure. Women students were more likely to intend to continue the pregnancy (76.9%, p < 0.05); however, students without siblings (68.2%, p < 0.01) and men and women students with higher scores for vocational identities who were raised in an academically oriented family were more likely to intend to terminate the pregnancy (p < 0.05). Therefore, gender and vocational identity were associated with decision-making following a positive result of Down syndrome. Further qualitative and quantitative studies on factors associated with decision-making following a positive result of Down syndrome are necessary to eliminate the burden and social barrier, including gender division of labor and the effect of vocational career for people wishing to parent a child with Down syndrome.

Death of children with Down syndrome by gestational age and cause

BACKGROUND

We often encounter preterm infants with Down syndrome (DS) who die in the neonatal intensive care unit (NICU). In this study, we examined survival until NICU discharge and assessed the developmental prognosis of preterm infants with DS.

METHODS

We retrospectively reviewed 416 infants with DS hospitalized during the past 27 years at our NICU.

RESULTS

Death occurred in 8/20 (40%) infants at <32 weeks' gestation, 11/23 (48%) at 32-33 weeks, 9/99 (9%) at 34-36 weeks, and 9/274 (3%) at >36 weeks. In total, 84% of infants who died and 25% of those who survived had a non-reassuring fetal status (p < 0.001). Sex, small-for-gestational-age status, and postnatal transport were not associated with death. The main causes of death were bronchopulmonary dysplasia in 4/8 (50%) infants at <32 weeks' gestation, transient abnormal myelopoiesis in 11/20 (55%) and lymphatic dysplasia in 6/20 (30%) at 32-36 weeks, and varied causes at >36 weeks. Among survivors born at <34 weeks' gestation, 6/19 (32%) aged >2 years had moderate or severe cerebral palsy.

CONCLUSIONS

These data on the high mortality and morbidity of preterm infants with DS may be useful for patient treatment and parent counseling in NICUs treating critically ill infants.

IMPACT

Most infants with Down syndrome born at <34 weeks' gestation are born by cesarean section because of the non-reassuring fetal status. The mortality rate before discharge for infants with Down syndrome born at <34 weeks' gestation was 40%, and 30% of survivors developed moderate or severe cerebral palsy. The risk of death due to bronchopulmonary dysplasia and pulmonary hypertension was high in very preterm infants with Down syndrome despite the absence of chorioamnionitis. Infants with Down syndrome were born 1-2 weeks earlier than unaffected controls.

Salivary microbiome in children with Down syndrome: a case-control study

BACKGROUND

Down syndrome (DS), a most frequently occurring genetic disorder, is associated with oral morphological abnormalities and higher incidence rates of oral diseases. Recent studies have analyzed the oral microbiome to elucidate their relationships with oral diseases and general health; however, reports on the oral microbiome in individuals with DS are scarce. This study aimed to characterize the oral microbiome in children with DS.

METHODS

A total of 54 children aged 1-13 years were enrolled in this case-control study. Of these children, 27 had DS (Case: DS group) and 27 were age-matched healthy children (Control: ND group). Saliva in the oral cavity was collected with a swab, cultured, and tested for cariogenic and periodontopathic bacteria by quantitative polymerase chain reaction (qPCR) detection, and the salivary microbiome was analyzed using next-generation sequencing. The student's t-test, Fisher's exact test, Mann-Whitney U test, and permutational multivariate analysis of variance were used for statistical analysis.

RESULTS

Results of culture and qPCR detection tests for cariogenic and periodontopathic bacteria showed no significant differences in the detected bacteria between the DS and ND groups, with the exception of a significantly higher detection rate of Candida albicans in children with DS with mixed dentition. A comparison of the salivary microbiomes by 16S sequencing showed no significant difference in α diversity; however, it showed a significant difference in β diversity. Children with DS had a higher relative abundance of Corynebacterium and Cardiobacterium, and lower relative abundance of TM7.

CONCLUSIONS

This study provided basic data on the salivary microbiome of children with DS and showed the microbiological markers peculiar to children with DS. However, further research to identify the relationship with oral diseases is warranted.

Down syndrome live births following assisted reproductive technology in Japan: a nationwide survey between 2007 and 2016

PURPOSE

The use of assisted reproductive technology (ART) and prenatal genetic testing have become more widespread in line with an increase in maternal age. However, the effect of the introduction of non-invasive prenatal testing (NIPT) in April 2013 on pregnancy outcomes in Japan, including the prevalence of Down syndrome live births following ART, has not been investigated. This study aimed to evaluate the trends in the prevalence of Down syndrome live births following ART in Japan.

METHODS

This population-based retrospective study used the Japanese nationwide ART registry. All clinical pregnancies resulting in live births, stillbirths, and termination of pregnancy (TOP) following ART from 2007 to 2016 were included. Pregnancy outcomes involving infants with Down syndrome were evaluated.

RESULTS

Among 351,808 pregnancies, the proportion of mothers with advanced age increased significantly from 2007 to 2016 (from 49.5 to 62.4% and 8.9 to 17.8% for mothers aged ≥ 35 and ≥ 40 years, respectively). The proportion of live births with Down syndrome was 77.3% in 2007, which remained consistent until 2012, but then decreased significantly to 45.1% after 2013 (P < 0.001). The prevalence of Down syndrome live births increased up to 2012 (19.5/10,000 live births), decreased significantly in 2013 (12.1/10,000 live births), and then remained almost stable (11.1-14.7/10,000 live births).

CONCLUSION

The introduction of NIPT balanced the prevalence of Down syndrome live births following ART with recent increasing maternal age in Japan.

Causes of death in patients with Down syndrome in 2014-2016: A population study in Japan

Despite the higher mortality rates in patients with Down syndrome compared with the general Japanese population, the life span has dramatically increased in Japan and other countries. We aimed to clarify recent causes of death in patients with Down syndrome in Japan. We calculated proportionate mortality and standardized mortality odds ratios (SMORs) among all deaths registered with Down syndrome as the cause of death (ICD‐10 code, Q90) in the Japanese National Death Registry Database in 2014–2016. In the study period, 762 in patients with Down syndrome died. The main causes of death were pneumonia/respiratory infections (20.5%), congenital malformations of the circulatory system (11.2%), other diseases of the circulatory system (9.2%), and aspiration pneumonia (8.4%). The SMORs (95% confidence intervals) were higher for natural death, defined as death of an elderly person with no other cause of death to be mentioned (55.73 [36.92–84.12]), early‐onset Alzheimer's disease, defined as Alzheimer's disease with onset <65 years of age (29.36 [16.44–52.44]), aspiration pneumonia (18.33 [14.03–23.96]), pneumonia/respiratory infections (8.11 [6.76–9.73]), congenital malformations of the circulatory system (8.07 [5.98–10.88]), and leukemia/lymphoma (2.16 [1.55–2.99]) but lower for malignant solid tumors (0.04 [0.02–0.06]) in patients with Down syndrome. Patients with Down syndrome had the greatest relative risk of dying from natural death, early‐onset Alzheimer's disease, and respiratory illnesses, highlighting the need for appropriate medical, health, and welfare services.

Hospitalisations due to respiratory syncytial virus infection in children with Down syndrome before and after palivizumab recommendation in Japan

AIM

Down syndrome has been considered an independent risk factor for respiratory syncytial virus (RSV) infection. Palivizumab, an anti-RSV humanised monoclonal antibody, was currently approved for all children with Down syndrome in Japan. To investigate the change in RSV-associated hospitalisation (RSVH) rates before and after the universal approval of palivizumab in Japan in 2013, we conducted a nationwide retrospective survey.

METHODS

We conducted a nationwide, retrospective, questionnaire survey across paediatric institutions in Japan. The recruited children with Down syndrome were divided into two groups: those born April 2010 to March 2013 (2010-2012 cohort) and those born April 2013 to March 2016 (2013-2015 cohort).

RESULTS

Of the 664 institutions, 321 (48.3%) replied, and a total of 3929 children with Down syndrome were registered. The percentage of children who received palivizumab increased from 49.2% to 82.2%. The cumulative RSVH rate showed a decreased trend in the 2013-2015 cohort (OR, 0.83; 95%CI, 0.63-1.10), while the rate of these children (without CHD and born at a gestational age ≥ 36 weeks) was significantly decreased in the 2013-2015 cohort (OR, 0.56; 95%CI, 0.34-0.92).

CONCLUSION

The cumulative RSVH rate tended to be decreased after approval for all children with Down syndrome although the result was not significant.

Changes in awareness and knowledge concerning mother-to-child infections among Japanese pregnant women between 2012 and 2018

This study aimed to investigate the long-term changes in awareness of and knowledge about mother-to-child infections across 6 years in Japan. A questionnaire survey was conducted at our facility from October 2012 to January 2018, and the study periods were divided into 4 phases comprising 16 months each. A multiple-choice questionnaire assessed participants’ awareness of the following 13 pathogens of mother-to-child infections: cytomegalovirus (CMV), Toxoplasma gondii (T. gondii), hepatitis B virus, rubella virus, herpes simplex virus, parvovirus B19, hepatitis C virus, human immunodeficiency virus, human T cell leukemia virus type-1, measles virus, varicella-zoster virus, Chlamydia trachomatis, and Treponema pallidum. For the selected four pathogens (i.e., CMV, rubella virus, T. gondii, and parvovirus B19), the questionnaire also evaluated participants’ knowledge of transmission routes, the most susceptible time of infection that could yield severe fetal disease during pregnancy, the maximum frequency of fetal infection in cases of maternal infection, and methods to prevent maternal infection. In total, 1433 pregnant Japanese women were included in this study. There was no secular change in awareness of the pathogens concerning mother-to-child infections over time, and we also clarified that the detailed knowledge of the four pathogens of typical mother-to-child infections did not improve. Since knowledge about methods to prevent maternal infection is still insufficient for all pathogens, further advocacy is required to prevent mother-to-child infections.

Secular trends in longevity among people with Down syndrome in Japan, 1995-2016

BACKGROUND

Life expectancy in Japan has increased dramatically and is one of the longest in the world. However, the changes in lifespan in Japanese individuals with congenital diseases remain unknown. We investigated secular changes in the lifespan of people with Down syndrome over the last 20 years.

METHODS

We observed secular trends in the number of stillbirths, deaths and the mortality rates at ages 20, 40, and 60 among all deaths registered with Down syndrome as the cause of death (ICD10 code: Q90) in the Japan national death registry database between 1995 and 2016. Changes in the median age at death between 1995-2005 and 2006-2016 were investigated based on sex and history of surgery.

RESULTS

We identified 240 stillbirths and 1,099 deaths in this period. The annual number of stillbirths and deaths above the age of 1 year increased, whereas the number of deaths below 1 year did not change. The proportional mortality indicator at ages 20, 40, and 60 increased from 21.7%, 11.7%, and 1.7% in 1995 to 69.9%, 66.7%, and 36.6% in 2016, respectively. The median age at death was higher in females, individuals without a surgical history, and deaths occurring in 2006-2016. The median age at death increased over the period in those without a surgical history.

CONCLUSIONS

The age at death among people with Down syndrome has increased over the last 20 years, with currently 1 in 3 persons living over 60 years, necessitating adequate social welfare services in this aging population.