Non-invasive fetal sex determination: impact on clinical practice

Prenatal fetal sex determination is undertaken in women at high risk of serious genetic disorders affecting a specific sex. Traditionally, this is undertaken by invasive testing, usually chorionic villus sampling, which carries a risk of miscarriage of around 1%. The identification of cell-free fetal DNA in the maternal circulation has allowed the development of 'non-invasive prenatal diagnostic tests', which permit fetal sex determination without risk to the pregnancy.     

Ethical issues and decision-making in fetal cardiology

BACKGROUND: As the technique of fetal ultrasound has developed, we have more opportunities to perform fetal echocardiography. Our knowledge about fetal diagnosis has been rapidly expanded. It is essential for the pediatricians to understand the ethical issues surrounding the fetal diagnosis. METHODS: We discussed these ethical issues at the 5th Annual Meeting of the Japanese Society of Fetal Cardiology in Fukuoka, Japan, 1999. I have reviewed the ethical issues brought up in the discussions. RESULTS: We have discussed many aspects of ethical issues. We should explain to parents before the fetal scan how and why the fetus is examined. It is very important to get written informed consent from the parents. It seems very difficult to inform of fetal diagnosis and support parents appropriately. We have to establish a system where obstetricians, neonatologists, cardiologists, nurses, midwives and medical social workers are cooperating in the perinatal center. CONCLUSION: We have many problems in the field of ethical issues. We have to keep discussing them. It is necessary to establish a team for fetal medicine in every perinatal hospital.     

Analysis of fetal DNA from maternal peripheral blood by lectin-polymerase chain reaction-single strand conformation polymorphism

Fetal nucleated cells in maternal peripheral blood are a non-invasive source of fetal DNA for prenatal genetic diagnosis. However, the number of fetal cells present in maternal peripheral blood is very small. Therefore, fetal cell enrichment is generally considered necessary to allow detection and subsequent genetic analysis of the rare fetal cells. In the study presented here, we performed fetal cell separation from maternal blood using galactose-specific lectin to concentrate fetal nucleated red blood cells (FNRBCs), and attempted paternal diagnosis using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). Fetal cell separation was performed using galactose-specific lectin on a PV-MeA coated slide. Twenty cells consisting of an NRBC and its surrounding 19 maternal cells were collected using laser microdissection for stable DNA amplification. DNA analysis was performed using three sequence tagged site markers (D13S270, D17S5, and D18S474) by PCR-SSCP. All seven cases were informative because they showed heterozygosity at least one locus in D13S270, D17S5, or D18S474, and paternal-specific bands were detected in all cases. These results suggest that our proposed lectin-laser-micromanipulation-PCR-SSCP method may contribute to the development of prenatal diagnosis.     

Prenatal Diagnosis and Fetal Therapy Utilizing Fetoscope*

Abstract Fetoscopy has not been familiar in Japan, probably due to the low frequency of its major indicated disorders. Recently this technique is drawing the interest by its unique ability to approach to the fetus directly. In this circumstance, fetoscopy itself, the indications, the usage in fetal therapy, and fetal electrocardiogram as an expanded apprication of fetoscopy are presented.     

胎儿免疫性房室传导阻滞研究进展

胎儿房室传导阻滞属于胎儿缓慢性心律失常。当母体血清抗-SSA/Ro、抗-SSB/La抗体阳性时,胎儿完全性房室传导阻滞发病率和相关围生期胎儿/新生儿死亡率显著升高。母体血清自身抗体可经胎盘转运进入胎儿体内,可能导致胎儿心脏传导系统免疫损伤,从而引起房室传导阻滞发生。如果能进行胎儿免疫性房室传导阻滞的早期诊断和及时干预,可能阻止病情进展,改善免疫性房室传导阻滞胎儿的预后并提高其生存率。文章综述胎儿免疫性房室传导阻滞的发病机制、危险因素、产前诊断、胎儿期干预及预后等。     

Beyond screening for chromosomal abnormalities: Advances in non-invasive diagnosis of single gene disorders and fetal exome sequencing

Emerging genomic technologies, largely based around next generation sequencing (NGS), are offering new promise for safer prenatal genetic diagnosis. These innovative approaches will improve screening for fetal aneuploidy, allow definitive non-invasive prenatal diagnosis (NIPD) of single gene disorders at an early gestational stage without the need for invasive testing, and improve our ability to detect monogenic disorders as the aetiology of fetal abnormalities. This presents clinicians and scientists with novel challenges as well as opportunities. In addition, the transformation of prenatal genetic testing arising from the introduction of whole genome, exome and targeted NGS produces unprecedented volumes of data requiring complex analysis and interpretation. Now translating these technologies to the clinic has become the goal of clinical genomics, transforming modern healthcare and personalized medicine. The achievement of this goal requires the most progressive technological tools for rapid high-throughput data generation at an affordable cost. Furthermore, as larger proportions of patients with genetic disease are identified we must be ready to offer appropriate genetic counselling to families and potential parents. In addition, the identification of novel treatment targets will continue to be explored, which is likely to introduce ethical considerations, particularly if genome editing techniques are included in these targeted treatments and transferred into mainstream personalized healthcare. Here we review the impact of NGS technology to analyse cell-free DNA (cfDNA) in maternal plasma to deliver NIPD for monogenic disorders and allow more comprehensive investigation of the abnormal fetus through the use of exome sequencing.     

Non-invasive prenatal diagnosis and determination of fetal Rh status

RhD blood group incompatibility between a pregnant woman and her fetus can result in maternal alloimmunization and consequent haemolytic disease of the newborn (HDN) in subsequent pregnancies. The D-negative blood group is found in 15% of whites, 3-5% of black Africans, and is rare in Asians. Recent technological advances in non-invasive prenatal determination of the fetal RHD status using cell-free fetal DNA (cffDNA) have opened new avenues for the management of D-negative pregnant women. In this review applications for the high risk women, as well as potential for routine screening will be discussed. The use of non-invasive prenatal diagnosis and the management of other blood incompatibilities will also be discussed.     

Prenatal diagnosis and fetal therapy of congenital cystic adenomatoid malformation type I of the lung: a report of five cases

ABSTRACT  We experienced five pregnancy cases with type I congenital cystic adenomatoid malformation (CCAM) of fetuses and summarized here their clinical characteristics, pregnancy outcomes, and fetal therapies. Four of five cases were prenatally diagnosed using magnetic resonance imaging (MRI) as having lung abnormality, and the remaining case was prenatally diagnosed as having congenital diaphragmatic herniation (CDH). One fetus underwent the puncture of cysts in the lung, and two fetuses received in utero thoracoshunts between cysts and the amniotic fluid cavity (thoracoamniotic shunt). One pregnancy ended in artificial termination at 17 gestational weeks, and 4 pregnancies succeeded in live births. All these 4 infants underwent surgical operations for CCAM, and 1 infant underwent an additional operation for CDH. The MRI examinations were useful to prenatally identify CCAM, and the in utero thoracoamniotic shunt appears to be beneficial in preventing lung hypoplasia in the affected fetuses.     

Outcome of fetal echocardiography: A 17 year single‐institution experience in Japan

Background: The aim of this retrospective study was to evaluate the influence of prenatal diagnosis on perinatal outcomes of congenital heart disease (CHD) over a 17 year period at a single center. Methods: The perinatal outcome of CHD in 146 patients diagnosed on fetal echocardiography between 1994 and 2010 were reviewed. The characteristics of 193 neonatal inpatients with CHD treated at the authors’ department between 2001 and 2010 were also analyzed; among the inpatients, 61 were diagnosed before birth (prenatal group) and 132 were diagnosed after birth (postnatal group). Results: Among the 146 patients prenatally diagnosed with CHD, the prenatal mortality, including abortion and stillbirth, decreased from 1994 to 2010. Among the 193 neonatal inpatients, the prenatal group had lower gestational age and bodyweight than the postnatal group. Further, the prenatal group had lower blood pH at admission, but no patient in that group experienced ductal shock, although six patients in the postnatal group did. The average dose of prostaglandin E1 used in duct‐dependent CHD was significantly lower in the prenatal group than in the postnatal group (3.4 vs. 4.6 ng/kg per min; P = 0.015). Conclusions: Prenatal diagnosis of CHD enables planned labor, prevents ductal shock, and reduces prostaglandin E1 side‐effects and medical expenditure.     

Fetal phenotypic analysis

Phenotypic analysis has been practised in many different ways, the most common being the recognition of normal and abnormal physical and biochemical characteristics and their patterns of inheritance. As different tools became available to analyze the characteristics of individuals the study of the phenotype and consequently of the genotype became more sophisticated. By the mid 1970’s ultrasonography became a major tool in the analysis of human disease, and more recently it has contributed to the analysis of the human fetal phenotype in utero. This method, when used in conjunction with cytogenetic and biochemical analysis of the amniotic fluid, constitutes the main thrust of genetic prenatal diagnosis today. This paper describes and proposes the systematic use of ultrasonography, in conjunction with biochemical and cytogenetic tests to examine pregnancies at risk of congenital and inherited diseases and those that show signs of abnormality. We have examined 1500 fetuses and have detected conditions that affect only one system, like the skeletal dysplasias (osteogenesis imperfecta, thanatophoric dysplasia, diastrophic dwarfism, achondrogenesis I, Jeune syndrome and many others), neural tube defects, gastroschisis, multiple congenital malformations syndromes (Vater, Vacterl, Weyers olygodactyly, Meckel syndrome, and others). The analysis of the functionality of the fetus is one of the major achievements of genetic prenatal diagnosis by ultrasonography.     

Chromosomal basis of recurrent fetal losses

Chromosome abnormalities constitute the single most etiological factor in spontaneous abortions and other fetal losses and include sporadic chromosome abnormalities such as monosomy, trisomy, triploidy, tetraploidy and chromosomal mosaicism. These errors either originate during gametogenesis or after fertilization during the early zygotic divisions. Based upon the information now available it is apparent that if a couple has had two fetal losses, the karyotypes of the abortuses are most likely to be concordant either both being normal or both being abnormal. Fetal losses may also be due to a chromosome abnormality carried by a parent in a clinically silent form such as a balanced translocation. A compilation of cytogenetic data from 17,112 parents (8,743 females and 8,369 males) revealed 517 instances of chromosome abnormalities, an incidence of 3 per cent (6% of couples). Approximately 50 per cent of all chromosome abnormalities detected were balanced reciprocal translocations, followed by balanced Robertsonian translocations (23%) and sex chromosome mosaicism in females (14%). Parental chromosome abnormalities are known to be factors in abnormal gametogenesis and zygote formation, and, therefore, prenatal diagnosis should be considered in future pregnancies. Further, even when parental karyotypes are normal, prenatal diagnosis should be offered to couples who have had two or more fetal losses due to their increased risk of having a fetus with a chromosome abnormality.     

Insights into fetal and neonatal development through analysis of cell-free RNA in body fluids

The use of cell-free nucleic acids in the circulation of pregnant women for noninvasive prenatal diagnosis is arguably one of the hottest current topics in prenatal medicine. Between 1997 and the present era this field has gone from basic research to clinical application for diagnosis of fetal gender and Rhesus D status. Over the next few years it is likely that noninvasive prenatal diagnosis for Down syndrome will also be possible. Here we summarize current and future clinical applications of analyzing cell-free fetal DNA and RNA in both maternal and neonatal body fluids, including maternal plasma, serum, whole blood, amniotic fluid, and neonatal saliva. We describe methods to evaluate normal and abnormal fetal and neonatal development using gene expression microarrays. We also discuss the ways in which differentially-regulated gene lists can advance knowledge of both fetal and neonatal biology, as well as suggest novel possibilities for fetal and neonatal treatment.     

The prenatal determination of fetal weight by dynamic scanning

An equation based on ultrasound measurements to estimate fetal weight must reflect the relationships between parameters of fetal size and growth as well as the change in fetal shape which occurs in relation to varying nutritional supplies. Four equations have been compared with respect to these demands. The material was collected from everyday practice in our hospital. Good results were obtained using two of the equations, and it was suggested that they may serve as valuable tools in studies of fetal growth.     

Fetal arrhythmias: Intrauterine diagnosis,treatment and prognosis

Fetal echocardiography can provide useful information for the evaluation of fetal arrhythmias. Between 1980 and 1993, 44 fetuses with arrhythmias were diagnosed in utero at 12 and 40 weeks of gestation in Kurume University Hospital. Fetal bradycardia, tachycardia and ectopic beats were revealed in 17, seven and 20 fetuses, respectively, and their clinical features and prognosis were evaluated. In the 17 fetuses with bradycardia, eight were associated with congenital heart defect, and six of these developed to fetal hydrops. Of the 17 fetuses, four died in utero, one was terminated, and six died after birth. The other six cases survived. Three of these had a pacemaker implanted after birth. In the seven fetuses with tachycardia, transplacental anti-arrhythmic drugs were administered in five cases and conversion of the arrhythmia was achieved in four. None of the cases was associated with any congenital heart defect, and none died. Three infants had paroxysmal tachycardia postnatally. In the 20 fetuses with ectopic beats, arrhythmia was observed postnatally in 10, but all of these were resolved within 3 months after birth. Fetal bradycardias carried a poor prognosis in most cases and further studies are required to establish effective treatment. Some cases of fetal tachycardia developed recurrent tachycardia postnatally. Close follow-up of the newborn is therefore necessary.     

Studies on human fetal tissues-II. Lipid composition of human fetal tissues in relation to gestational age,fetal size and maternal nutritional status

When lipids of different tissues were compared for the period 16–24 weeks of gest ation, the liver has the highest concentration of all the lipid components studied. The concentrations in the small intestine were close to that of the liver in the case of the neutral lipids. The lung and heart were found to have comparable concentrations of various lipids. Fetal growth retardation seems to be associated with a higher concentration of cholesterol in the liver, the lung and small intestine. Lower values for phospholipid concentration and phospholipid to cholesterol ratio were observed in the lung, heart and small intestine with such retardation. These studies suggest the delayed maturation of these tissues, as these lipids play an important role in the maintenance of cellular integrity, structure and function of plasma membrane as well as subcellular membranes.     

胎肝器官发生与组织学发育的研究进展

肝脏是体内最大的器官,其代谢、解毒和体内稳态的重要性已得到很好的了解。肝脏的形成是一个复杂的过程,必定涉及多个基因和信号分子。显然从研究肝脏发育中获得的知识将有助于指导肝脏移植、基因治疗和组织工程等领域,且会获益于整个人类社会。     

Repeated adverse fetal outcome in pregnancy complicated by uncontrolled maternal phenylketonuria

Phenylketonuria in pregnancy carries with it an increased risk of spontaneous abortion and development of a fetus that is affected by the maternal phenylketonuria syndrome. This syndrome is characterized by low birthweight, congenital heart disease, microcephaly, childhood growth failure, and cognitive impairment. It is the result of the hyperphenylalaninemia that accompanies the phenylketonuric state, and may therefore be avoided by maintaining maternal serum phenylalanine levels within the normal range. Phenylalanine is an essential amino acid and may be controlled by dietary manipulation. Presented here is a case history of a woman with phenylketonuria who was unable to satisfactorily control her serum phenylalanine levels in each of her three pregnancies. All three children were adversely affected by the fetopathy of the maternal phenylketonuria syndrome, each with evidence of growth failure and impaired neurodevelopment. This patient illustrates the difficulties that may be encountered when providing obstetric care to the woman with phenylketonuria who is not able or not willing to restrict her dietary intake of phenylalanine. The discussion includes consideration of management strategies, including dietary therapy and legal intervention.     

胎儿先天性心脏病介入治疗进展

既往观点认为,一旦胎儿患有左心发育不良综合征(HLHS)等严重心血管畸形,结局就只能是出生后功能性单心室循环、心脏移植或中止妊娠.到目前为止,开放性胎儿心脏外科技术尚不成熟,而通过胎儿心脏介入治疗技术可以在很大程度上阻止因先天性心脏病引起的胎儿水肿、自发性流产或胎儿死亡,促进发育不良的心室重新发育,形成生后的双心室循环,重塑右室流出道梗阻胎儿的肺血管床等,改善了胎儿严重心血管畸形的预后.这些进步在很大程度上依赖于对胎儿先天性心脏病病理生理学特点的准确判断.超声技术的发展以及其他评价手段的进步可促进目前还比较有限的胎儿先天性心脏病介入治疗进一步发展.     

Accuracy of telediagnosis of fetal heart disease using ultrasound images transmitted via the Internet

We verified the feasibility of telediagnosis of fetal disease by (i) grading telediagnosis by a pediatric cardiologist into five confidence levels; and (ii) comparison of fetal telediagnosis with hands‐on fetal diagnosis or postnatal diagnosis. In 114 patients suspected of having heart disease (real time, n = 15; recorded image transmission, n = 99), 79 patients were in level 5 (excellent), 17 in level 4 (good), eight in level 3 (fair), 10 in level 2 (poor), and no patients in level 1 (bad). The average was 4.5, and in 96 patients (84% of all) telediagnosis was accurate (above 4), whereas in 18 patients it was inaccurate (level 2 or 3). In re‐examination of 25 patients, telediagnosis was confirmed in patients in level 4 and 5, whereas heart disease was missed in patients in levels 2 or 3. The correct diagnosis matched the high confidence level of a specialist based on recognizable transmitted images.