HLA typing of cultured amniotic cells for the prenatal diagnosis of complement C4 deficiency

It has recently been reported that HLA typing can be used for the prenatal diagnosis of the HLA-linked monogenetic disease, congenital adrenal hyperplasia (21-hydroxylase deficiency type). We describe here the use of HLA typing of cultured amniotic cells for the prenatal diagnosis of another HLA-linked disease, complement C4 deficiency. Although C4 is actually coded for by genes at two very closely linked loci, mapping near the HLA-B locus, absolute C4 deficiency behaves genetically like a monogenetic autosomal recessive disease linked to HLA. The HLA typing results for amniotic cells from a pregnancy at risk for C4 deficiency predicted that the fetus would share only one HLA haplotype with the affected child and would therefore be a clinically normal heterozygous carrier of the C4 deficiency alleles with half-normal levels of C4 activity. These predictions were confirmed after delivery.     

Fetal death rates in mothers of children with trisomy 21 (Down syndrome)

Women under 25 years at the birth of a child with trisomy 21 (Down syndrome) appear to have an increased risk of having another child with a trisomy. If the risk of recurrence is due solely to an increased production of trisomic conceptions, women with an affected child should have a rate of spontaneous abortion higher than average, since the majority of aneuploid conceptuses are expected to be aborted. We examined fetal loss rates among the other pregnancies of 545 women delivered of a child with trisomy 21 and compared the observed loss rates with those which would be expected were the relative risk for these women for an aneuploid recognized pregnancy the same as their relative risk for an aneuploid livebirth as reported by others. Overall loss rates in their prior pregnancies were greatest for women who were 20–24 years old at the time of birth of the proband. Moreover, the observed rate of fetal loss for this group of women (33·8%) was at least as high as that predicted from their relative risk for a trisomic livebirth. By contrast, the observed fetal loss rates for women 25–39 years of age at the proband's birth did not differ from the rates predicted on the assumption that their risk for a trisomic recognized pregnancy was not increased, as the livebirth data suggested. The results of this study suggest that women under 25 years at the birth of a child with trisomy 21 have a significantly higher rate of fetal loss in their prior pregnancies than women delivered of the trisomic child at older ages.     

Cigarette smoking and the intention to quit among pregnant smokers

Research has demonstrated that smoking during pregnancy has deleterious effects on the health of the unborn child as well as the mother. The present study examined whether pregnant smokers would have a greater intention to quit smoking, whether the stage of pregnancy would influence the intention to quit, and whether variables which have predicted cessation among pregnant smokers would also predict intention to quit. The results indicated that pregnant women did not have a significantly greater intention to quit smoking compared to nonpregnant smokers, despite the health risks to their child. Women who were further along in their pregnancy and women who smoked more cigarettes on a daily basis demonstrated the least intention to quit. Notably, women in the first trimester showed the greatest intention to quit, suggesting that pregnant women may be most receptive to quitting during their first trimester.     

Attitudes towards prenatal diagnosis and carrier screening for cystic fibrosis among the parents of patients in a paediatric cystic fibrosis clinic.

The parents of all children attending the Royal Brompton National Heart and Lung Hospital cystic fibrosis paediatric clinic were asked to complete an anonymous postal questionnaire addressing attitudes towards prenatal diagnosis and population carrier screening for cystic fibrosis (CF); 65% (170/261) of parents responded. Of the respondents, 92% would support the introduction of a population screening test to detect carriers of CF and 19% felt such a test should be mandatory. A total of 64% of CF parents felt they would choose not to have any further children in the knowledge that they were both carriers, 74% would choose to have a prenatal test if they became pregnant, 44% would consider terminating an affected pregnancy, 33% would not, and 23% were unsure. Overall, 72% of respondents indicated they would choose to avoid having a further child with CF either by not having further children or by terminating an affected pregnancy.     

Counseling needs and attitudes toward prenatal diagnosis and abortion in fragile-X families

The genetic counseling need of 32 women of normal intelligence at-risk for having children with the fragile-X syndrome (FXS) were determined by a questionnaire study which included assessment of their attitudes toward prenatal diagnosis and the option of pregnancy termination. Eighteen (56%) of the women had one or more children with the FXS and 14 (44%) had no affected children. Twenty-six (81%) of the subjects stated that they would choose to have prenatal diagnosis and 9 (28%) indicated they would terminate an affected pregnancy. There was no significant difference between women who had affected children and those who did not have affected children, nor between Catholics and non-Catholics regarding acceptance of prenatal diagnosis. Catholic women were less likely to consider pregnancy termination than non-Catholics, but the majority of subjects (56%) were unsure what they would do if a fetus they were carrying was found to be affected. Issues the subjects considered most important for discussion with a genetic counselor included: 1) availability of treatment, 2) risk for having an affected grand child, 3) expectations for future functioning of affected children, and 4) availability of prenatal diagnosis.     

Assessment of reproductive risk and intentions by mothers of children with hemophilia

Thirty-five mothers of children with hemophilia were studied in order to ascertain the impact of hemophilia on family planning. Attitudes about reproductive risks and prenatal diagnosis were also examined. The most important factors influencing family planning in this group were parental fulfillment and availability of medical care and education for their affected child. Although 79% of mothers viewed their reproductive risk as moderate to very high, 57% indicated that their reproductive plans had not changed even with this knowledge. While 43% of the group would consider prenatal diagnosis, only 17% would terminate a pregnancy if the fetus was found to have hemophilia. Of those interested in prenatal diagnosis, the majority were interested in knowing if the fetus was affected but would not consider termination of the pregnancy. The majority of mothers in the group did not view having a child with hemophilia as an insurmountable burden on their lives. Therefore, the disease appeared to have little impact on family planning.     

Perception of burden among at-risk women of raising a child with fragile-X syndrome

On a self-administered questionnaire 31 women at-risk for bearing children with fragile-X syndrome (FXS) were asked to judge the magnitude of the problems they perceived to be associated with raising an affected child. An age- and education-matched group of women with no family history of FXS was asked to predict the seriousness of problems they might encounter were they to bear a child with a handicapping condition. Mothers of children with FXS reported that they were experiencing fewer and different problems than FXS relatives who did not have affected children predicted they themselves would experience. The perceptions of the burden of raising a handicapped child of FXS relatives without affected children were more similar to those of the comparison group than to those of FXS mothers. This suggests that women who raise a child with FXS learn to cope with an unchangeable situation, and consequently their perceptions of the burdens ease with time. A direct relationship between the acceptability of selective abortion and the perceived seriousness of the problems associated with having an affected child was observed.     

Attitudes to predictive DNA testing in familial adenomatous polyposis.

Attitudes to predictive DNA testing for familial adenomatous polyposis were documented in 62 affected adults. Patient views on prenatal testing and termination of pregnancy for this disorder were sought, as were opinions on the most suitable age to offer predictive testing for at risk children and the most appropriate age to begin screening. While 15 (24%) of those questioned stated that they would proceed to termination of pregnancy if a prenatal test indicated that the unborn baby was affected, in clinical practice no one has yet requested this option. Six (10%) people who had refrained from having children for fear of passing on the polyposis gene felt that the arrival of prenatal testing would enable them to consider planning a family. The majority of patients (93%) said they would like their children tested by DNA analysis at birth or in infancy, but felt that 10 to 12 years was the most appropriate time to discuss the diagnosis with the child.     

Transmission and prenatal diagnosis of the T9176C mitochondrial DNA mutation

A family presented with three affected children with Leigh syndrome, a progressive neurodegenerative disorder. Analysis of the OXPHOS complexes in muscle of two affected patients showed an increase in activity of pyruvate dehydrogenase and a decrease of complex V activity. Mutation analysis revealed the T9176C mutation in the mtATPase 6 gene (OMIM 516060) and the mutation load was above 90% in the patients. Unaffected maternal relatives were tested for carrier-ship and one of them, with a mutation load of 55% in blood, was pregnant with her first child. The possibility of prenatal diagnosis was evaluated. The main problem was the lack of data on genotype-phenotype associations for the T9176C mutation and on variation of the mutation percentage in tissues and in time. Therefore, multiple tissues of affected and unaffected carriers were analysed. Eventually, prenatal diagnosis was offered with understanding by the couple that there could be considerable uncertainty in the interpretation of the results. Prenatal diagnosis was carried out twice on cultured and uncultured chorion villi and amniotic fluid cells. The result was a mutation percentage just below the assumed threshold of expression (90%). The couple decided to continue the pregnancy and an apparently healthy child was born with an as yet unclear prognosis. This is the first prenatal diagnosis for a carrier of the T9176C mutation. Prenatal diagnosis for this mutation is technically reliable, but the prognostic predictions are not straightforward.     

Neurofibromatosis type 1 (NF1): knowledge, experience, and reproductive decisions of affected patients and families.

Eighty-one subjects (56 affected patients and 25 parents of isolated affected cases) from 63 families with neurofibromatosis type 1 (NF1) on the North Western Regional Genetic Family Register (NWRGFR) were interviewed. Patients were interviewed either before (n = 26) or after (n = 55) genetic counselling. In the group as a whole, knowledge of the clinical features and the genetic aspects of the condition was poor (mean score 7 within the range of 0 to 18). The following factors were significantly associated with higher knowledge: (1) genetic counselling, (2) higher social class, (3) child with NF1, (4) when NF1 had influenced reproductive decisions, (5) young age at diagnosis, and (6) member of a patient support group. The majority of the affected subjects perceived themselves to be more severely affected than by medical classification, with persons who had been diagnosed later in life, had a child with NF1, or who were concerned about the cosmetic aspects of the disease perceiving themselves to be more severely affected. Assessment of the psychosocial effects of NF1 at different stages of life showed that 63% of affected subjects experienced difficulties at school and 48% said that the condition, particularly cosmetic aspects, caused anxiety during adolescence (n = 54). These difficulties may have contributed to later problems with career attainment and confidence in relationships. Seventy-seven percent of parents stated that their child was experiencing difficulties at school relating to NF1 (n = 51). Of the subjects at risk of having a child with NF1 and who knew about NF1 before having their family (n = 32), 45% said that it had influenced their reproductive decisions. Of 29 subjects who were still considering children, 41% wished to have prenatal diagnosis in a future pregnancy, but only three subjects stated that they would terminate an affected pregnancy.     

Age of onset in Huntington''s disease: lack of parental age effect.

In a recent publication Brackenridge and Teltscher (1975) concluded that the age of onset of Huntington's disease was in part a function of the age of the transmitting parent at the time of birth of a subsequently affected child. Their analysis suggested that the younger the parent was at the time of birth of the subsequently affected child, the later in life symptoms of disease would appear in the child. The data of Brackenridge and Teltscher have been statistically reevaluated here, and this analysis fails to support their conclusion. Consequently it would be irresponsible to counsel persons at risk for Huntington's disease to plan families early in life.     

Reproductive decision making of aunts and uncles of a child with cystic fibrosis: genetic risk perception and attitudes toward carrier identification and prenatal diagnosis.

This paper evaluates the perceived genetic risk, the perceived burden, the impact on reproductive decision making, and the attitudes of aunts and uncles of a child with cystic fibrosis toward carrier identification, prenatal diagnosis, and pregnancy termination. A mailed questionnaire was sent to the aunts and uncles of 32 CF children (1) who attended the Paediatric Department of the University Hospital and (2) whose parents agreed to give the names and addresses of their sibs. The results for the 109 respondents aged less than 40 years are discussed. About one-fourth of them was aware of the "approximate" level of the risk to be a carrier of the CF gene and/or of the risk of having a CF child themselves. Nevertheless the subjective evaluation of the genetic risk has played a part in the reproductive decision-making process of at least 39% of the respondents. About three-fourths would (probably) make use of heterozygote detection and would (probably) ask for prenatal diagnosis should they become pregnant. It is striking that less than half of the group would interrupt the pregnancy should the fetus be affected. The intention to use prenatal diagnosis was significantly correlated with age and educational level while the acceptance of pregnancy interruption was significantly correlated with perceived burden, respondents' age, and health situation of the proband.     

Novel universal approach for preimplantation genetic diagnosis of beta-thalassaemia in combination with HLA matching of embryos

BACKGROUND: Beta-Thalassaemia results from co-inheritance of two mutant beta-globin alleles. Allogeneic cord blood cell transplantation (CBT) from an HLA-identical sibling donor is an excellent treatment option for beta-thalassaemia. In families with an affected child and willing to have another child, IVF followed by preimplantation genetic diagnosis (PGD) can be applied to exclude affected embryos. Furthermore, healthy embryos could be HLA matched with the affected child so that cord blood from the future newborn can be used to transplant the affected sibling. METHODS: We developed an indirect single-cell HLA typing technique based on the use of a bank of seven microsatellite markers within the HLA locus from which four informative and evenly distributed markers were selected. RESULTS: The methodology was validated in three beta-thalassaemia families having six ovarian stimulation cycles in view of IVF and PGD. Six PGD cycles were performed in two families. On 58 embryos tested, the combined PCR was successful in 54 (93%). Two transfers were done and one clinical pregnancy was obtained. Using confirmatory analysis on 50 embryos, the accuracy for HLA typing was 100%. CONCLUSION: This strategy offers a new therapeutic option for patients with beta-thalassaemia and other monogenic diseases that can be cured with CBT.     

Reproductive attitudes of couples having a child with cystic fibrosis in Brittany (France)

Cystic fibrosis (CF) has an incidence of one in 2,636 livebirths and a carrier rate of one in 26 inhabitants in Brittany. One objective of a major enquiry among parents having a CF child as well as CF adolescents and adults was to evaluate the reproductive behavior of 124 couples attending a CF care center. Knowledge of recurrence risk resulted in deciding against further progeny or in reducing the number of children (average number of children: 1.96; ideal mean number of children: 3.7). Thirty-five percent adopted or changed their method of contraception after the birth of their affected child, but the change was due to the birth of the CF child in only 14.3% of the couples. Prenatal diagnosis (PD) was favored by 95.1%, and 41.2% had used it; 68.6% were in favor of pregnancy interruption for CF and 76.2% would interrupt the pregnancy should PD reveal that their fetus had CF. All 123 respondents thought that genetic counseling was useful, but only 87.1% knew of its availability. Our results are quite different from those previously published. Although results could be population-specific, one cannot exclude the fact that they reflect a change of attitudes among parents, the other studies being much older.     

Autism spectrum disorders: a qualitative study of attitudes toward prenatal genetic testing and termination decisions of affected pregnancies

In the United States, prenatal genetic testing (PGT) for Autism Spectrum Disorders (ASD) is currently available via clinical genetic services. Such testing may inform parents about their unborn child's risk for ASD, prepare parents for the birth of an affected infant, and allow them to arrange for early interventions. Although PGT for autism has potential benefits, the associated ethical, legal, and social implications (ELSI) should be considered. This first qualitative study employed a hypothetical scenario to explore the attitudes toward PGT and termination decisions of 42 parents of children with ASD. Over half of the participants expressed willingness to undergo PGT for autism. Reasons included better preparation for birth, early and better treatment, termination of affected pregnancy, contribution to research, and curiosity. Of the 31 parents who were either willing or unsure about undergoing the PGT, approximately three‐fourths would continue their hypothetical affected pregnancies. Explanations included preparation for birth of the child, bonding or acceptance of existing ASD‐affected children, apprehensions about test limitations, and religious concerns. Parents who reported they would terminate the affected pregnancy in this hypothetical situation were primarily Asians. This study contributes to the growing understanding of the ELSI aspects of PGT in clinical practice.     

An archival study of decision-making in child custody disputes.

Investigation files and court records of 282 disputed child-custody cases (San Diego, 1982) were coded and analyzed to determine predictors of judicial decision. Log-linear analysis of physical custody decisions as a function of factors contained in the files suggested that three categories of factors (mother, father, and child) were linked causally to a counselor's recommendation, which was linked subsequently to the judge's decision. Judicial decisions could be predicted accurately by a model that took very few factors into account. Only two factors directly affected the judge; counselor-recommendation and child preference. The major factor that influenced decisions was counselor recommendation (60% of the cases); cases that lacked this recommendation were predicted by an inferential measure of the child's preference (15% of the cases).     

Preimplantation genetic diagnosis: patients' experiences and attitudes

BACKGROUND: This study aims to report the experiences and attitudes of patients who have undergone preimplantation genetic diagnosis (PGD). The extent to which this technique is acceptable to the individuals for whom it is intended is relatively unexplored, and remains a crucial issue that may ultimately determine the value of PGD as an alternative to prenatal diagnosis in high-risk couples. METHODS: An information sheet and questionnaire was distributed to 67 couples who had been treated at the Hammersmith Hospital, London and the Dexeus Institute, Barcelona. RESULTS: One-third of patients had an affected child, over half had previous experience of conventional prenatal diagnosis and over one-third had had terminations of pregnancy because of a genetic risk. Patients perceive the main advantage of PGD to be that only unaffected embryos are transferred to the uterus and thus therapeutic termination of pregnancy can be avoided; the main disadvantage is the low success rate. A total of 41% of patients found the treatment cycle extremely stressful, and, of the 20 patients who had experienced both prenatal diagnosis and PGD, 40% of patients found PGD less stressful, although 35% experienced more stress. Of those couples who contemplated a further pregnancy 76% would choose PGD, 16% would opt for prenatal diagnosis, and 8% no tests at all. CONCLUSIONS: The experience of prenatal diagnosis and termination of pregnancy can be an unwelcome memory and this leads to a demand for an alternative approach. Our data suggest that PGD is acceptable to patients and is a valuable alternative to prenatal diagnosis.     

Diagnosis and management of the phenotypic spectrum of twins with Beckwith‐Wiedemann syndrome

Beckwith‐Wiedemann syndrome (BWS) is an overgrowth disorder with a heterogeneous phenotypic spectrum. There is an increased prevalence of monozygotic twinning in BWS. Given the epigenetic nature and phenotypic spectrum that defines BWS, twins are often discordant for clinical features, and clinicians are faced with the challenge of diagnosing and managing these twins. We present a cohort of multiple pregnancies in which one or more child from each pregnancy was diagnosed with BWS. We conducted a chart review of monochorionic and dichorionic gestations. Clinical scores for monochorionic twins demonstrated phenotypic discordance between the proband and twin. Based on linear regression analysis, a higher clinical score in the proband correlated with larger phenotypic discordance between twin siblings. Despite phenotypic discordance, however, we observed a consistent additive clinical score for a pregnancy (proband's plus twin's scores from a pregnancy). This idea of a finite degree of affectedness for a pregnancy implies a finite number of epigenetically affected cells. This further corroborates the idea that timing of monozygotic monochorionic twinning correlates with the disruption of establishment and/or maintenance of imprinting. The difference in clinical score between a proband and their twin may be due to diffused mosaicism, whereby there is an asymmetric distribution of affected cells among the multiple fetuses in a monozygotic monochorionic pregnancy, leading to a spectrum of variably affected phenotypes. Based on these findings, we recommend an algorithm for a conservative approach to clinically evaluate all children in a monozygotic multiple gestation affected by BWS.     

Patient and parental attitudes toward genetic screening and its implications at an adult cystic fibrosis centre

General population screening for cystic fibrosis carrier status in the United Kingdom would detect 72% of at-risk couples. Proper counselling would allow these couples to make informed reproductive choices, including the possibility of prenatal diagnosis and the termination of an affected pregnancy. However, children with cystic fibrosis born in this decade, given optimum treatment, now have an average life expectancy of 40 years, and there is no unanimity of opinion on how, where, when, or even if, screening should be offered. The purpose of this questionnaire-based study was to examine the attitudes of an adult clinic population who have grown up with cystic fibrosis, and of their parents, towards genetic screening programmes and the controversies and ethical dilemmas surrounding such programmes in cystic fibrosis. Both patients and parents supported prenatal screening (88% and 90%) and the option of terminating an affected pregnancy (68% and 84%). Only 22% of patients and 10% of parents felt that screening should be limited to families with a history of cystic fibrosis, and 19% and 6%, respectively, that prenatal diagnosis should be restricted to those with a previous child with cystic fibrosis. Despite the negative aspects of any screening programme and the acknowledged ethical problems peculiar to cystic fibrosis, the conclusion of our patients and parents who have lived intimately with the illness is that there should be the option of utilising information available from genetic screening for cystic fibrosis to guide reproductive choices. Pilot programmes to define the optimum management of such screening should continue.     

The Fetus as an Allograft: a Longitudinal Study of Normal Human Pregnancies Studied with Mixed Lymphocyte Cultures between Mother-Father and Mother-Child

A longitudinal investigation of the mixed lymphocyte culture (MLC) response during pregnancy between mother and father, between mother and child, and between the mother and an indifferent lymphocyte pool has been carried out, using starting values before pregnancy and a cryobiological freezing system that allows in vitro playback of the immunological course of pregnancy. Lymphocyte and serum samples from twenty-two pregnant women taken before and during pregnancy, at delivery, and after delivery were used. The study shows that the mother reacts during the course of pregnancy with an increasing MLC response to the father, which is replaced at delivery by a decrease in response and a subsequent increase after delivery. It is also shown that the mother reacts to the child in a similar manner at about half the level of reaction to the father. The mother also reacts similarly to a pool of indifferent lymphocytes. The MLC reactions mentioned are affected by both non-pregnant and pregnant serum, leading to a moderation of the MLC reaction in relation to that carried out in neutral AB serum. In addition, there seems to be cooperation between cellular and humoral factors, since the MLC reaction to the child curried out in relevant autologous serum seems to show a decreasing response during the course of pregnancy, in accordance with increasing tolerance of the fetal allograft.