[Incidence of chromosomal anomalies and congenital malformations in children born from assisted fertilization]

The introduction and widespread application of Assisted Reproductive Techniques (ART) have raised major concern about the offspring 's health. The incidence of congenital and chromosomal anomalies after standard In Vitro Fertilization and Embryo Transfer seems to be similar to that expected in the general population. The prevalence of congenital malformations does not seem to be higher in children conceived by ICSI. On the other hand, it seems that there is a slight risk for transmission of chromosomal aberration of paternal origin and a certain risk of de novo sex-chromosomal and structural aberrations after ICSI. We report the results of the follow-up of 938 children conceived in our public ART by standard IVF(649) and by ICSI(289) from 21-2-1987 to 30-6-1999. The incidence of the congenital malformations results of the 1.8% (17/938); the incidence of chromosomal anomalies results 0.5% (5/938). The incidence of congenital malformations and chromosomal anomalies results 1.5% (10/649) and 0.6% (4/649), respectively, for standard IVF and 2.4% (7/289) and 0.3% (1/289) for ICSI. Our data seems to be reassuring but the incidence of chromosomal anomalies in ICSI children needs further investigation.

Identification and characterization of satellite III subfamilies to the acrocentric chromosomes

The centromeres and the short arms of the five pairs of acrocentric chromosomes in humans are composed of tandemly ordered repetitive DNA. Previous studies have suggested that the exchanges between acrocentric chromosomes have resulted in concerted evolution of different DNA sequences in their short arms. The acrocentric chromosomes are clinically relevant since they are involved in Robertsonian translocation formation and non-disjunction resulting in aneuploidy. Here we have identified seven new satellite III repetitive DNA subfamilies, determined their nucleotide sequences and established their chromosomal distributions on the short arms of the acrocentric chromosomes. Knowledge of these related sequences may help to elucidate the molecular basis of Robertsonian translocation formation.

Satellite III sequences on 14p and their relevance to Robertsonian translocation formation

Robertsonian translocations (ROBs) are the most common rearrangements in humans, contributing significantly to genetic imbalance, fetal wastage, mental retardation and birth defects. Rob(14q21q) and rob(13q14q), which are formed predominantly during female meiosis, comprise the majority (approximately 85%) of all ROBs. Previous studies have shown that the breakpoints are consistently located within specific regions of the proximal short arms of chromosomes 13, 14, and 21. The high prevalence of these translocations, the consistent breakpoints found, and the fact that roughly 50% of cases occur sporadically suggest that the sequences at or near the breakpoints confer susceptibility to chromosome rearrangement and that the rearrangements occur through a specific mechanism. To investigate this hypothesis, we developed hamster-human somatic cell hybrids derived from de novo rob(14q21q) patients that contained the translocated chromosome segregated from the other acrocentric chromosomes. We determined the physical order of five satellite III subfamilies on 14p, and investigated their involvement in formation of these de novo translocations.

A prospective controlled study of karyotyping for 430 consecutive babies conceived through intracytoplasmic sperm injection

OBJECTIVE

To compare the karyotype of babies conceived through ICSI with that of naturally conceived babies.

DESIGN

Prospective controlled study.

SETTING

The Egyptian IVF-ET Center, Cairo, Egypt.

PATIENT(S)

Four hundred and thirty babies conceived through ICSI and 430 babies conceived naturally.

INTERVENTION(S)

ICSI and karyotyping.

MAIN OUTCOME MEASURE(S)

Abnormal karyotype.

RESULT(S)

Four hundred and thirty consecutive babies conceived through ICSI who were delivered in one hospital had 15 abnormal karyotypes (3.5%). Of the 15 babies, 7 were of female phenotype and 8 of male phenotype. Six babies had sex chromosome anomalies, 8 had autosomal anomalies, and 1 had combined sex chromosome and autosomal anomalies. A control group of 430 consecutive babies conceived naturally who were delivered in one hospital had no abnormal karyotype. The difference between the two groups was significant (P<.001).

CONCLUSION(S)

ICSI carries a small but significant increased risk of abnormal karyotyping to the offspring. This risk appears to be equally distributed between autosomal and sex chromosome anomalies.

Single umbilical artery is associated with an increased incidence of structural and chromosomal anomalies and growth restriction

The objective to characterize neonatal outcome associated with ultrasonographic identification of a single umbilical artery. Pregnancies diagnosed with single umbilical artery antenatally were identified. All prenatal/antenatal and pediatric records were reviewed for maternal demographics, associated anomalies, karyotypic analysis, pregnancy complications, and neonatal outcome. Twenty-seven pregnancies complicated by fetal single umbilical artery were identified. Of the 27 pregnancies, 5 (18.5%) underwent pregnancy termination and 1 (3.7%) experienced fetal demise. Of the 21 liveborn infants, 4 (19%) died within the first year of life. Sixty-seven percent of fetuses had an associated structural anomaly. Sixteen of the 27 pregnancies underwent amniocentesis and 7 of these were chromosomally abnormal. All of the karyotypically abnormal fetuses had a structural defect in addition to the single umbilical artery. Of the six fetuses without any associated structural or chromosomal anomalies, three (50%) demonstrated growth restriction. Single umbilical artery is relatively rare finding. When a single umbilical artery is identified, a vigilant search for associated anomalies should be undertaken. Pregnancies identified as having fetuses with associated structural anomalies should be offered amniocentesis. Pregnancies with isolated single umbilical artery should be carefully monitored for evidence of fetal growth restriction.

Congenital subependymal pseudocysts: own data and meta-analysis of the literature

BACKGROUND

Congenital subependymal pseudocysts are incidental findings that are found in 0.5-5.2% of neonates during postmortem examination or head ultrasonography. In our institution we detected 10 neonates with CSEPC.

OBJECTIVE

To investigate associated etiological factors, morphologic characteristics and outcome of CSEPC.

METHODS

We performed a meta-analysis of the literature on CSEPC (1967-98), including our 10 cases.

RESULTS

A total of 256 cases of CSEPC were analyzed. Ultrasound diagnosed 77.6% of CSEPC; 48.8% were bilateral and 53.4% were located in the caudothalamic groove or head of caudate nucleus. Altogether, 93.5% resolved during 1-12 months of ultrasonographic follow-up. Compared to the general neonatal population, the following features were more prevalent in the CSEPC population: prematurity, maternal vaginal bleeding, preeclamptic toxemia, intrauterine growth restriction, asphyxia, fetal cytomegalovirus and rubella infections, congenital malformations, chromosomal aberrations, infant mortality, and neurodevelopmental handicap. The risk for neurodevelopmental handicap was significantly higher when CSEPC were associated with fetal infections, IUGR, malformations and chromosomal aberrations, or persistence of CSEPC during follow-up. CSEPC infants without any of these four conditions had a low risk for neurodevelopmental handicap.

CONCLUSIONS

CSEPC are morphologic features of various underlying conditions encountered in the fetus. Association of CSEPC with IUGR, fetal infections, malformations and chromosomal aberrations or persistence of CSEPC indicates a higher risk for future neurodevelopmental handicaps, probably because of the deleterious effects on the fetal brain that are inherent in these conditions. A favorable outcome is expected in the absence of these risk factors.

[The results of cytogenetic survey in liquidators of the Chernobyl nuclear accident]

The article represents results of long cytogenetic survey among liquidators of Chernobyl accident. The parameters studied are frequency of unstable chromosomal aberrations and frequency of symmetrical translocations. The authors show that, in spite of long term after irradiation, average frequency of cells with dicentrics and centric fusions (unstable chromosomal aberrations) remains relatively high. Discussion includes possible use of cytogenetic methods in reconstruction of absorbed radiation doses in many years after exposure.

PML-RARA fusion transcripts in irradiated and normal hematopoietic cells

It is believed that two important factors in the genesis of reciprocal chromosomal translocations in malignant cells are the physical proximity of the involved regions and local structural features of the chromatin fiber that make them more susceptible to breakage and rearrangement. In this work we sought to investigate whether PML-RARA fusion transcripts, characteristic of acute promyelocytic leukemia (APL), could be induced by a clastogenic agent in cells known to have, a priori, a favorable spatial distribution of these genes. A lymphoid-cell line, lacking the t(15;17) but having the PML and RARA genes in close proximity in specific phases of the cell cycle, was irradiated with 10 Gy of (60)Co, and the incidence of PML-RARA transcripts was analyzed by a highly sensitive PCR assay. Despite gene proximity, typical PML-RARA transcripts were only rarely detected in irradiated cells. The same phenomenon was observed at similar frequency in control non-irradiated cells. These findings made us investigate whether such transcripts could also be detected in peripheral blood cells from normal individuals. PML-RARA transcripts were observed at low frequencies in isolated lymphoid and granulocytic cell populations, with similar incidence in both cell types. The data thus indicate that the PML and RARA genes are not particularly susceptible to the clastogenic effects of gamma-irradiation, and that, similar to what has been reported for other chromosomal translocations, transcriptionally active PML-RARA rearrangements can be generated in normal hematopoietic cells of different lineages without apparent oncogenic consequences.

Chromosomal mosaicisms during prenatal diagnosis

Chromosomal mosaicism during prenatal diagnosis has been a major concern. Nondisjunctional events can lead to mosaicism in a number of ways, including failure of chromosomal pairing, failure to separate, anaphase lag and abnormal segregation. We provide a concise review on various types of mosaicism with their clinical significance.

Chromosomal regions involved in the pathogenesis of osteosarcomas

The comparative genomic hybridization technique (CGH) was used to identify common chromosomal imbalances in osteosarcomas (OS), which frequently display complex karyotypic changes. We analyzed 13 high-grade primary tumors, 5 corresponding cell lines, 2 primary tumors grade 2, and 1 recurrent tumor from a total of 16 patients. Some of the CGH results have been verified by fluorescence in situ hybridization (FISH) studies. Gains of chromosomal material were more frequent than losses. Most common gains were observed at 8q (11 cases), 4q (9 cases), 7q (8 cases), 5p (7 cases), and 1p (8 cases). The smallest regions of overlap have been narrowed down to 8q23 (10 cases), 4q12-13 (8 cases), 5p13-14 (7 cases), 7q31-32 (7 cases), 8q21 (7 cases), and 4q28-31 (5 cases). These data demonstrate that a number of chromosomal regions and even two distinct loci on 4q and 8q are involved in the pathogenesis of OS, with gain of 4q12-13 chromosomal material representing a newly identified locus. Seven of 16 cases displayed, besides gain of 8q23 sequences, gain of MYC copies in CGH and FISH. Previous CGH reports confined gain of 8q material to 8cen-q13, 8q21.3-8q22, and 8q23-qter, whereas our data suggest that the loci 8q21 and 8q23-24 are affected in the development of OS. In contrast to recent reports, copy number increases at 8q and 1q21 did not have an unfavorable impact on prognosis in the present series. Genes Chromosomes Cancer 28:329-336, 2000.

Socioeconomic inequalities in risk of congenital anomaly

AIMS

To investigate socioeconomic inequalities in the risk of congenital anomalies, focusing on risk of specific anomaly subgroups.

METHODS

A total of 858 cases of congenital anomaly and 1764 non-malformed control births were collected between 1986 and 1993 from four UK congenital malformation registers, for the purposes of a European multicentre case control study on congenital anomaly risk near hazardous waste landfill sites. As a measure of socioeconomic status, cases and controls were given a value for the area level Carstairs deprivation index, by linking the postcode of residence at birth to census enumeration districts (areas of approximately 150 households).

RESULTS

Risk of non-chromosomal anomalies increased with increasing socioeconomic deprivation. The risk in the most deprived quintile of the deprivation index was 40% higher than in the most affluent quintile. Some malformation subgroups also showed increasing risk with increasing deprivation: all cardiac defects, malformations of the cardiac septa, malformations of the digestive system, and multiple malformations. No evidence for socioeconomic variation was found for other non-chromosomal malformation groups, including neural tube defects and oral clefts. A decreasing risk with increasing deprivation found for all chromosomal malformations and Down's syndrome in unadjusted analyses, occurred mainly as a result of differences in the maternal age distribution between social classes.

CONCLUSION

Our data, although based on limited numbers of cases and geographical coverage, suggest that more deprived populations have a higher risk of congenital anomalies of non-chromosomal origin and some specific anomalies. Larger studies are needed to confirm these findings and to explore their aetiological implications.

The Chernobyl accident and its consequences: update at the millennium

A marked increase in the incidence of papillary thyroid cancer in children has been documented in regions of the former Soviet Union most heavily contaminated by radioactive fallout from the Chernobyl nuclear power plant accident in April 1986. Accumulation of radioactive iodines by normal iodine trapping mechanisms resulted in significant radiation doses to the thyroid gland. Although it has long been known that thyroidal radiation resulted in nuclear and chromosomal abnormalities visible by light microscopy, modern molecular biology techniques are beginning to identify much smaller alterations in chromosomal coding sequences that are associated with malignant transformation. Although stable chromosomal abnormalities can be detected in Chernobyl-associated thyroid cancers, they are much less prevalent than in thyroid cancers developing after external beam irradiation. However, several unique chromosomal breakpoints have been described in radiation-associated thyroid cancers that are not commonly found in spontaneously occurring thyroid cancer. Furthermore, activation of specific subtypes of the ret/PTC tyrosine kinase oncogene appears to be more common in radiation-associated thyroid cancers than in spontaneous thyroid cancers. In summary, thyroid cancers developing in the aftermath of the Chernobyl accident provide a unique opportunity to search for chromosomal abnormalities that may be specific for radiation-induced thyroid cancer.

Sperm quality may adversely affect the chromosome constitution of embryos that result from intracytoplasmic sperm injection

OBJECTIVE

To determine whether the high rate of chromosomal abnormalities in the embryos of an infertile couple were caused by a paternal factor that may have involved the sperm centriole.

DESIGN

Case report.

SETTING

Private IVF program.

PATIENT(S)

An infertile couple who underwent IVF-ET because of severe male factor infertility and endometriosis.

INTERVENTION(S)

Preimplantation genetic diagnosis of chromosomal abnormalities in embryos derived from two cycles of ICSI in which the husband's sperm was used and one in which donor sperm was used.

MAIN OUTCOME MEASURE(S)

Preimplantation genetic diagnosis with fluorescence in situ hybridization using probes for chromosomes X, Y, 13, 16, 18, and 21, and determination of hCG levels.

RESULT(S)

Most of the embryos derived from the cycles in which the husband's sperm was used were chromosomally abnormal (82%), whereas all the embryos derived from the cycle in which donor sperm was used were chromosomally normal. The cycle in which donor sperm was used resulted in an ongoing pregnancy.

CONCLUSION(S)

Paternal factors, which most likely derive from the centrosome, can contribute to numerical chromosomal abnormalities, which in turn may predispose to implantation failure.

[Limitations of reproductive medicine from an andrological/urological point of view]

Since the first child was born after in-vitro fertilization in 1978, different techniques of ovarian stimulation, oocyte retrieval and embryo culture have improved significantly. The development of microinjection techniques was a mile stone in reproductive medicine. Even in cases of severe impairment of semen quality, using the Intracytoplasmic Sperm Injection (ICSI), pregnancy rates of approximately 20 % per treatment cycle can be achieved. However for using artificial reproductive techniques (ART) the female age is a major limiting factor as well as the development of premature ovarian failure (POF). Crucial for the male is the question whether or not sperm cells can be retrieved. Today an interdisciplinary approach is recommended to take care of the afflicted couple in order to address the complex problem of infertility. There is evidence that children born after microinjection techniques bare a higher risk for chromosomal aberrations compared to the normal population. However rates of major malformations seem to be identical in both groups. An evaluation of the potential risks and efforts and an extensive counseling of the infertile couple has to be taken before initiating invasive ART.

Development of the human dispermic embryo

In a recent CD-ROM, we portrayed the microstructure of the pre-implantation human embryo (Sathananthan et al., 1999), which was a multimedia production with computer colour-enhanced electron micrographs of mainly monospermic embryos. This disk portrays light and electron micrographs of over 250 tripronuclear (3PN), dispermic, human embryos during pre-implantation development, viewed in thick and thin Araldite sections, as well as appearances of whole embryos flat embedded in Araldite blocks visualized with the light microscope. The 100 figures were computerized (IBM TIFF format), edited and labelled using Adobe Photoshop 5. Some of the figures were coloured on computer. The early development of 3PN embryos overtly resembles that of normal embryos but there are important differences in their microstructure which are portrayed in this presentation. This is a multicentric study involving researchers from four IVF centres.

Trisomy 18 in Kuwait

BACKGROUND

Trisomy 18 (Edwards' syndrome, T18) is the second most common trisomy in man. We describe 118 children with regular T18 who were ascertained clinically and cytogenetically in the Kuwait Medical Genetics Centre during 1980-1997.

METHODS

Ascertainment of T18 cases was performed shortly after birth. Chromosomal studies were carried out in addition to other relevant investigations. To investigate the factors associated with T18, a case-control study was carried out with 131 normal healthy newborns. Studied factors included maternal and paternal age, birth order, abortion, associated malformation, and survival. Multiple logistic regression analysis was used to adjust for confounding between variables.

RESULTS

There was a preponderance of females among T18 cases (female:male ratio 2.1:1). The majority of T18 cases (53%) died before the second week of life. The most common associated anomalies were: congenital heart (38.1%) and gastrointestinal (25.4%). Multiplicity of malformations was also observed. Significant seasonal variation in T18 cases was detected with a peak in spring. Of the 118 T18 cases, 59 were delivered during 1994-1997 (average overall T18 birth prevalence rate 8.95 per 10 000 live births [95% CI: 6.66-11.23]). Concerning maternal age, 30.5% of the T18 cases' mothers were > or =35 years compared to 10.7% in the control group. The difference was statistically significant, P = 0.002. Logistic regression analysis showed that maternal age >30 years was a significant risk factor for T18, after adjusting for confounding with paternal age. Paternal age and abortion were not found to be significant risk factors.

CONCLUSION

Trisomy 18 birth prevalence rate is high in Kuwait with advanced maternal age as a significant risk factor.

[Chromosome aberrations as a bio-dosimetric test of space radiation (experimental data from the seeds of higher plants)]

The authors analyzed the data about seeds of higher plants obtained in space experiments from several days to a year and a half in duration, and ground-based simulation studies on beams of accelerated heavy ions by the universal biological criterion of the chromosome aberrations. The criterion was also used to compare these data with those about lymphocytes in human peripheric blood in vitro. The number of aberrant cells, including cells with multiple aberrations, grew with mission duration, absorbed dose, and fluence of heavy charged particles as well as the topography of particles traverse of cells. Methodical dimensions of the test-object as a detector to evaluate the biological effects of and risk from space radiation in long-term space missions are considered.

[Medical pathology due to trinucleotide repeats]

Trinucleotide repeat expansion is responsible for ten human diseases described so far. Four types of repeats are involved in these expansions, with type, number and position in the gene varying from one disease to another. In some fragile sites, the trinucleotide repeat is found to be enlarged to 200 or more. Smaller expansions have been found within coding regions of some genes that are associated with neurodegenerative diseases, such as Huntington's disease. The continuous expansion of the trinucleotide repeats in subsequent generations explains the genetic anticipation, peculiar to these disorders. Recently, it was shown that two expanded minisatellite sequences are also involved in both progressive myoclonus epilepsy type 1 and distamycin A-sensitive fragile site, FRA16B. This form of peculiar heredity is very important because of its relationship with some of the common human degenerative diseases.

Syndromes associated with immunodeficiency

Immunodeficiency often has a genetic basis. Immune defects are the predominant manifestation in primary immunodeficiency disorders, and immune defects may also be associated with a number of other recognizable syndromes. There are 45 recognized primary immunodeficiency disorders, but immunodeficiency has been reported in 105 other syndromes. Abnormalities associated with these syndromes include growth deficiency (19 syndromes with disproportionate or proportionate short stature); specific organ system dysfunction (39 with gastrointestinal, dermatologic, or neurologic abnormalities); inborn errors of metabolism (17); miscellaneous anomalies (17); and chromosome anomalies (13). In most of these disorders, immunodeficiency is present in only a portion of the patients. However, in 49 syndromes, immunodeficiency is present in the vast majority. We review the clinical manifestations of each syndrome and delineate the associated immune defects. For most, the underlying mechanism linking the immune defect and other anomalies is unclear. Recognition of these conditions involving both the immune and other organ systems may facilitate accurate diagnosis and management, as well as yield information regarding genes critical for the development of the involved systems.

General ageing and ovarian ageing

The age related decrease in female fertility is associated with a decrease in follicle numbers and oocyte quality. Meiotic division errors, mitochondrial DNA mutations and ageing itself have been suggested to play a part in the age associated reduction in oocyte quality. During the past decades several hypothesis have been proposed, trying to explain the underlying mechanisms. However, none of them is yet conclusive. This review will consider the main hypotheses regarding the age related reduction in oocyte quality. This will be reviewed together with recent results of studies analysing a possible relationship between ageing and ovarian ageing. On the basis of our own results and those presented in the literature, it is concluded that ovarian ageing may only be related to specific aspects of general ageing.

[Intracytoplasmic sperm injection]

The first results of intracytoplasmic sperm injection (ICSI) in Norway are presented. Acceptable fertilization rates were obtained for all indications; severe male infertility, as well as moderately reduced sperm quality where in vitro fertilization (IVF) and embryo transfer had previously failed. Furthermore, in cases where IVF had failed despite normal sperm quality, fertilization rates of 50-60% were achieved. The overall pregnancy rate was 24.9% per embryo transfer, and the live pregnancy rate per started cycle was 13.4%. As expected, the results improved with experience. The results were greatly influenced by the age of the female. In the age group 34 years or less, the total pregnancy rate per cycle was 32.4%, with a miscarriage rate of 24.2%. In the age group 35 years or more, (42% of the study group), the total pregnancy rate per embryo transfer was 15.2%, with a miscarriage rate of 75%. The corresponding implantation rates were 17.4% and 7.9% respectively. 23 children have been born so far, none with major malformations or chromosome abnormality symptoms.

Recurrence risk of a serious, noninherited chromosomal abnormality

OBJECTIVE

To investigate the recurrence risk of a serious, noninherited chromosomal abnormality.

DESIGN

Prospective and retrospective analysis.

SETTING

University-based prenatal diagnosis clinic.

PATIENT(S)

Data on 240 pregnancies in 165 couples after a pregnancy with a serious chromosomal abnormality.

RESULT(S)

Autosomic trisomic pregnancy had occurred in 133 families. In these families, there were 193 new pregnancies 132 in women under 35 years and 61 in women over 35 years. The recurrence rate was 2.3% in the women under 35 years and 8.2% in the women over 35 years. Pregnancy had occurred in 18 families with a sex-chromosomal abnormality. In these families, there were 24 new pregnancies, 21 in women under 35 years and 3 in women over 35 years. All pregnancies were chromosomally normal. Some other serious chromosomal abnormality had occurred in 14 families. In these families, there were 23 new pregnancies. Chromosomal abnormality recurred in two families: in a woman under 35 years and in a woman over 35 years.

CONCLUSION(S)

The high recurrence rate of chromosomal abnormalities even in women under 35 years warrants fetal chromosomal investigation in new pregnancies.

Risk of congenital anomalies in children of parents occupationally exposed to low level ionising radiation

OBJECTIVES

To evaluate the risk of having a child with a congenital anomaly in relation to occupational exposure to low level ionising radiation in the pre-conception period.

METHODS

A case-control study based on the Canadian congenital anomalies registry used record linkage techniques to identify congenital anomalies among male and female workers in Canada's largest electric company. Cases were defined as parents of a child with a congenital anomaly born between April 1979 and December 1986 who had a congenital anomaly diagnosed within the first year of life. Controls were an individually matched sample of parents of a liveborn child without an anomaly. Risk of congenital anomaly was assessed in relation to parental exposure to ionising radiation acquired through work within a nuclear generating station of an electric power company. Exposure was assessed according to employment, whether or not the worker was monitored for radiation exposure, and quantitative estimates of radiation dose.

RESULTS

Employment within the electric power industry was not associated with an increased risk of congenital anomalies in the offspring of mothers or fathers. Risk estimates for workers monitored (those who are likely to be exposed to ionising radiation) were 1.75 (95% confidence interval (95% CI) 0.86 to 3.55) for mothers and 0.84 (95% CI 0.68 to 1.05) for fathers. Exposure for fathers before conception, defined cumulatively and for six months before conception, was not associated with increased risk of anomalies in their offspring. There were no significant increases in risk found between type of anomaly and any measure of exposure, although the statistical power in these groups was limited. The study had insufficient numbers to evaluate the effects of ionising radiation in mothers as only three mothers had recorded doses > 0 mSv.

CONCLUSIONS

Overall, workers in a nuclear power industry, and specifically those exposed before conception to low levels of ionising radiation, do not appear to be at an increased risk of having a liveborn child with a congenital anomaly.

Treatment-related chromosome abnormalities in human embryos

Mosaicism was studied in good quality embryos from four different centres in order to assess the effects of follicular induction and exposure to laboratory conditions on chromosomal status. The donated embryos were fully biopsied and analysed by fluorescence in-situ hybridization using probes for chromosomes X, Y, 13, 18 and 21, simultaneously. The number of abnormal cells present indicated the division at which mosaicism first occurred (4/4 cells at first division, 2/4 cells at second, 2/8 at third). The rate of mosaicism in embryos from different centres varied greatly (P < 0.001). Most of the mosaic embryos were obtained before 1991. In one clinic increased mosaicism was found in embryos obtained before 1991 when compared to embryos obtained thereafter. The results suggest that certain culture conditions and/or hormonal stimulation protocols may induce chromosomal abnormalities and partly explain differences in pregnancy rates between in-vitro fertilization centres.

Myelodysplastic syndrome presenting as third malignancy after non-Hodgkin's lymphoma and osteosarcoma

The patient was initially diagnosed as having non-Hodgkin's lymphoma and was cured following treatment with prednisolone, vincristine, daunorubicin, 1-asparaginase, and cyclophosphamide. Seven years and two months later, he developed osteosarcoma in his right femur. He received chemotherapy consisting of methotrexate, carboplatin, etoposide, and ifosfamide and again obtained remission. After 2 years and 7 months, however, he was found to have pancytopenia with morphological abnormalities in the erythroid and myeloid series. Diagnosis of myelodysplastic syndrome (MDS) was made. Cytogenetic analysis of bone marrow cells revealed -5 and -7, which is typical for secondary MDS. This is a rare case of third malignancy presumably caused by alkylating agents.

The sensitivity of biological tissue to ultrasound

Mammalian tissues have differing sensitivities to damage by physical agents such as ultrasound. This article evaluates the scientific data in terms of known physical mechanisms of interaction and the impact on pre- and postnatal tissues. Actively dividing cells of the embryonic and fetal central nervous system are most readily disturbed. As a diagnostic ultrasound beam envelopes a small volume of tissue, it is possible that the effects of mild disturbance may not be detected unless major neural pathways are involved. There is evidence that ultrasound can be detected by the central nervous system; however, this does not necessarily imply that the bioeffect is hazardous to the fetus. Biologically significant temperature increases can occur at or near to bone in the fetus from the second trimester, if the beam is held stationary for more than 30 s in some pulsed Doppler applications. In this way, sensory organs that are encased in bone may be susceptible to heating by conduction. Reports in animals and humans of retarded growth and development following frequent exposures to diagnostic ultrasound, in the absence of significant heating, are difficult to explain from the current knowledge of ultrasound mechanisms. There is no evidence of cavitation effects occurring in the soft tissues of the fetus when exposed to diagnostic ultrasound; however, the possibility exists that such effects may be enhanced by the introduction of echo-contrast agents.

Sonographic diagnosis of fetal upper extremity dysmorphology: significance and outcome

The aim of this study was to determine the etiology, associated anomalies and outcome of fetuses with postural deformities and contractures of the upper extremities detected sonographically. Fifty-four fetuses with sonographically detected postural anomalies of the upper extremities were identified from our database. Sonographic findings and associated anomalies were tabulated on the basis of the original sonogram. Perinatal follow-up and/or karyotype were available in 52 cases from a review of the maternal and newborn medical records and pathology reports. Of the 52 fetuses with sonographically detected anomalies of the upper extremities, 44 (85%) were non-survivors and eight (15%) were survivors. Forty-three fetuses had associated sonographic abnormalities. Karyotyping performed in 44 cases revealed 26 cases (59%) of aneuploidy, with trisomy 18 accounting for 23/26 (88%). In the setting of a normal karyotype, a variety of genetic disorders were found, including syndromes involving the fetal dyskinesia/akinesia sequence. Disturbances in amniotic fluid occurred in 48% of the cases (24 fetuses with polyhydramnios and one with oligohydramnios). In conclusion, the sonographic detection of postural abnormalities of the upper extremities carries a guarded prognosis, with survival in 15% of fetuses and a high incidence of chromosomal defects.

[Genetic risks associated with intracytoplasmic sperm injection]

Preliminary data available for ICSI demonstrate an increased incidence of chromosome abnormalities in infertile men, their spermatozoa and in the preimplantation embryos obtained after microinjection. The injection itself may not result in a significant increase in damage to the meiotic spindle provided care is taken to orient the polar body away to the site of injection. It is therefore of paramount importance to continue all investigations on larger series to properly evaluate the safety of the ICSI procedure.

Health of children born to medical radiographers

OBJECTIVES

To develop a reliable method for collecting information on reproductive outcome in an occupational setting; and to investigate the health of children born to medical radiographers.

METHODS

The study population comprised 6730 members of the College of Radiographers who were, at the time of survey; aged between 30 and 64 years, on the current membership file of the College, and were resident in Britain.

RESULTS

The postal method developed proved to be reliable, with around 87% of questionnaires being returned. The observed frequencies of reproductive events were broadly in line with findings from other studies: of the 9208 pregnancies reported, 83% were livebirths, 12% were miscarriages (gestational age < 20 weeks), 1% were stillbirths (gestational age > or = 20 weeks), and 1% were other rarer spontaneous adverse events (ectopic pregnancy, blighted ovum, and hydatidiform mole). There was little difference between men and women in the frequency of adverse reproductive events reported, with the exception that male radiographers reported fewer medical terminations, the proportions being 3.1% and 1.4% for women and men respectively. Among children, the overall risks of major congenital malformation (RR 1.0, 95%CI 0.9-1.2), chromosomal anomaly (RR 1.4, 95%CI 0.8-2.3), and cancer (RR 1.2 95%CI 0.7-2.0) were as expected based on general population rates. Borderline excesses of chromosomal anomalies other than Down's syndrome in the children of female radiographers (RR 3.9, 95%CI 1.3-9.0, based on five observations), and cancer in the children of male radiographers (RR 2.7, 95%CI 0.9-6.5, based on five observations) were noted. The numbers on which these risks are based are small and the findings should be interpreted cautiously.

CONCLUSIONS

The postal methods developed for obtaining information about reproductive events and child health proved to be reliable in men, as well as in women. Overall, the findings for medical radiographers are reassuring. Dose-response relations could not, however, be examined as long term dose records of radiographers are not routinely kept in an accessible form.

Risk of fetal chromosomal abnormalities in idiopathic polyhydramnios

BACKGROUND

Polyhydramnios is often associated with fetal anatomical abnormalities; thus chromosome analysis is indicated for fetuses with those indications. However, chromosome analysis for patients with idiopathic polyhydramnios is often overlooked. This is an attempt to evaluate the necessity for chromosome analysis in pregnancies with idiopathic polyhydramnios.

METHODS

Genetic amniocentesis or percutaneous umbilical blood sampling was done in 33 cases with idiopathic polyhydramnios which appeared at 26 to 34 weeks' gestation. To exclude false idiopathic polyhydramniotic cases, a level II sonographic examination was carefully performed for those fetuses with abnormal chromosome. Autopsy ultrasound examination and X-ray examination were done in four neonates with abnormal karyotypes, and the results were compared with prenatal sonographic findings.

RESULTS

Seven (21.2%) out of the 33 cases were, surprisingly found to have chromosomal abnormalities. Three out of the seven cases were diagnosed to have fetal anatomical defects, at a repeated level II sono-graphic examination. The incidence of fetal chromosome abnormalities in idiopathic polyhydramnios was 13.3% (4/30). After 7 cases of women older than 34 years and 3 cases with false idiopathic polyhydramnios were excluded, the incidence of chromosomal abnormalities in pregnancies of those under 34 years of age with idiopathic polyhydramnios was 8.3% (2/24).

CONCLUSIONS

According to the results of this study and other papers, the incidence of chromosomal abnormalities in fetuses with idiopathic polyhydramnios is much higher than that for maternal age specific risk at 34 years of age. Therefore fetal chromosome analysis for pregnancies with idiopathic polyhydramnios is recommended to avoid unnecessary Cesarean sections and deliveries of viable babies with abnormal chromosomes.

Solar activity cycle and the incidence of foetal chromosome abnormalities detected at prenatal diagnosis

We studied 2001 foetuses during the period of minimal solar activity of solar cycle 21 and 2265 foetuses during the period of maximal solar activity of solar cycle 22, in all women aged 37 years and over who underwent free prenatal diagnosis in four hospitals in the greater Tel Aviv area. There were no significant differences in the total incidence of chromosomal abnormalities or of trisomy between the two periods (2.15% and 1.8% versus 2.34% and 2.12%, respectively). However, the trend of excessive incidence of chromosomal abnormalities in the period of maximal solar activity suggests that a prospective study in a large population would be required to rule out any possible effect of extreme solar activity.