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PubMed2002

Correlation between rare chromosomal abnormalities and prenatal ultrasound findings.

Our objective was to examine ultrasound findings with outcomes in cases of rare chromosomal abnormalities diagnosed during pregnancy. Results of cytogenetic studies obtained from amniocenteses and chorionic villus samplings (CVS) from 1994-2000 were reviewed. Only those examples of rare chromosomal abnormalities with little information on the associated outcome were included. Cases of autosomal trisomy (13, 18, and 21), sex chromosome aneuploidy, and reciprocal or Robertsonian translocations were excluded. Ultrasound findings and outcomes were reviewed. In all, 8,642 procedures of amniocenteses and 557 of CVS were performed; 21 cases met the inclusion criteria. Parental karyotypes were obtained for 19 couples and the karyotypic abnormalities were de novo in 13. Abnormal ultrasound findings were present in 14 pregnancies, with the following outcomes: seven underwent dilatation and evacuation (D&E), with abnormal findings in two (although examination was limited by fragmentation); one medical termination with micrognathia and low-set ears; one fetal demise; one neonatal demise; three surviving neonates with abnormalities (one each with congenital kyphosis, hydronephrosis, and hypotonia), and one newborn was normal. There were seven patients without abnormal ultrasound findings with the following outcomes: three underwent D&E, with abnormal findings in two, one child with a colobomatous optic nerve, and two apparently normal infants. Follow-up was not available in one patient. We conclude that when rare karyotypes and ultrasound abnormalities are present, poor outcomes are likely. Even with normal ultrasound findings, abnormalities may be present. These data may assist in counseling patients when testing reveals such chromosomal abnormalities.

Adult↗
PubMed1995

Use of decision analysis to evaluate patients' choices of diagnostic prenatal test.

Women with a family history of a chromosomal or genetic abnormality must weigh several factors in choosing between amniocentesis and chorionic villus sampling. We compared the prenatal test choices of three such women with those of decision analytic models that incorporated their preferences. Patient preferences were assessed using visual linear rating scales. Threshold analysis was used to determine preference ranges, and stochastic sensitivity analysis to provide confidence levels, for each choice of test. The test choices of patients and decision analytic models agreed in one case, and disagreed in two cases. In one of the latter two cases, stochastic and threshold analyses showed the disagreement to be slight; for small shifts in preference differences for first- vs. second-trimester diagnosis, or first- vs. second-trimester therapeutic abortion, patient and decision model would have agreed. In the other, stochastic analysis showed their differences to be large; there were no thresholds for early diagnosis, or for early therapeutic abortion, that would have led to agreement between patient and model. In the two cases in which patient and decision model agreed or slightly disagreed, the patients had made their own choice of prenatal test. In the case in which patient and decision model strongly disagreed, the patient's physician had shared in the choice of test. Decision analysis can be useful in analyzing prenatal test choices based on individual preferences for pregnancy outcomes. When choices of patients and decision models do not agree, examination of the locus of decision making (patient vs. physician) may help resolve apparent differences.

Abortion, Induced↗
PubMed2005

Forty-two supernumerary marker chromosomes (SMCs) in 43,273 prenatal samples: chromosomal distribution, clinical findings, and UPD studies.

Fluorescence in situ hybridization (FISH) analyses were performed on supernumerary marker chromosomes (SMCs) detected in 43,273 prenatal diagnoses over a period of 11 years, 1993-2003. A total of 42 pregnancies with SMC were identified, indicating a prevalence of one in 1032. A total of 15 SMCs were endowed with detectable euchromatin (prevalence, 1/2884), including six SMCs containing the cat eye critical region (CECR) on chromosome 22q11.21 (1/7212). De novo SMCs were found in 29 pregnancies (1/1492), including 14 euchromatic SMCs (48.2%). Follow-up studies were available for 24 cases. Nine pregnancies (37.5%) were terminated; two children (8.3%) were born with Pallister-Killian syndrome and cat eye syndrome (CES), respectively; 13 children (54.1%) showed apparently normal development. Familial SMCs were identified in 13 pregnancies (1/3328) from 11 unrelated women. They were all acrocentric. In all, 10 were heterochromatic and one was an extra der(22)t(11;22) chromosome. A total of 12 cases were available for follow-up. One pregnancy was terminated due to anhydramnios, spina bifida, and cystic-dysplastic kidneys; one child suffered from a der(22) syndrome; 10 children (83.3%) appeared unaffected. Studies for uniparental disomy were performed on seven pregnancies and revealed a case of maternal heterodisomy for chromosome 22. So far this is the largest FISH study of prenatally ascertained SMCs and the first study with detailed data on the prevalence. Findings illustrate the spectrum and clinical outcomes of prenatally diagnosed SMCs, and indicate a higher frequency of SMCs than generally assumed.

Abnormalities, Multiple↗
PubMed2006

Postnatal follow-up of prenatally diagnosed trisomy 16 mosaicism.

OBJECTIVE: To determine the long-term outcome of pregnancies prenatally diagnosed with trisomy 16 and identify variables associated with the outcome. METHODS: We reviewed all published and our unpublished data from trisomy 16 pregnancies for which outcomes were available for children of greater than 1 year of age. RESULTS: Nineteen cases were diagnosed with trisomy 16 on chorionic villus sampling (CVS) and 17 cases at amniocentesis. Age at last follow-up ranges from 1 to 13 years. Among the CVS group, four out of five patients, with a birth weight and/or length below -2 SD and postnatal growth information, showed catch-up growth (80%). Among the amniotic fluid (AF) group, the birth weight was available in 13 cases. Eleven of the 13 cases had a birth weight less than -2 SD. In eight cases, the length was also below -2 SD (length data unavailable in one case). Nine out of ten cases (90%) and seven out of eight (87.5%) showed catch-up growth for weight and length, respectively. In terms of development, no cases of CVS mosaicism had global developmental delay. One child had a history of delay in speech development. Among the AF-detected cases, 4/17 cases had global developmental delay. All four children with global developmental delay had more than one major malformation compared to 6 out of 32 children in the group with normal development (p = 0.004). The finding of uniparental disomy (UPD) was not associated with developmental delay. CONCLUSIONS: The majority of prenatally diagnosed trisomy 16 mosaic cases have a good postnatal outcome. However, the finding of mosaicism on AF and the presence of major congenital anomalies are associated with an increased risk of developmental delay.

Amniocentesis↗
PubMed1995

Limb defects after chorionic villus sampling.

OBJECTIVE: To clarify the association between limb defects and chorionic villus sampling (CVS). METHODS: Questionnaires were sent to 165 major obstetric units in Taiwan to survey the incidence of limb defects with and without CVS exposure during 1991. Limb defects with CVS exposure from September 1990 to June 1992 were also surveyed. The spectrum of limb defects in CVS-exposed and general populations were compared by the Poisson test. RESULTS: The incidence of limb defects in the surveyed general population in 1991 was 0.032% and that with CVS exposure was 0.294%, a statistically significant difference (P < .001). The incidence of severe limb defects in the general population was 0.0026% and that with CVS exposure was 0.22%, also statistically significant (P < .001). Twenty-nine cases of limb defects after CVS were reported from September 1990 until June 1992: 19 cases with transverse limb reduction, two with mid-palm reduction, seven with adactyly or hypodactyly, and one with syndactyly. Four cases also had oromandibular-limb hypogenesis syndrome. CONCLUSIONS: The incidence of limb defects, especially the severe types, was increased after CVS. The spectrum of limb defects with CVS exposure was more severe than the limb defects seen in the general population and showed a specific pattern ranging from hypodactyly, adactyly, and transverse limb reduction, to oromandibular-limb hypogenesis. A correlation between the severity of limb defects and the timing of CVS was suggested.

Abnormalities, Multiple↗
PubMed2004

Late first-trimester invasive prenatal diagnosis: results of an international randomized trial.

OBJECTIVE: To assess, in a randomized trial, the safety and accuracy of amniocentesis and transabdominal chorionic villus sampling (CVS) performed at 11-14 weeks of gestation, given that this time frame is increasingly relevant to early trisomy screening. METHODS: We compared amniocentesis with CVS from 77 to 104 days of gestation in a randomized trial in a predominantly advanced maternal age population. Before randomization, the feasibility of both procedures was confirmed by ultrasonography, and experienced operators performed sampling under ultrasound guidance; conventional cytogenetic analysis was employed. The primary outcome measure was a composite of fetal loss plus preterm delivery before 28 weeks of gestation in cytogenetically normal pregnancies. RESULTS: We randomized 3,775 women into 2 groups (1,914 to CVS; 1,861 to amniocentesis), which were comparable at baseline. More than 99.6% had the assigned procedure, and 99.9% were followed through delivery. In contrast to previous thinking, in the cytogenetically normal cohort (n = 3,698), no difference in primary study outcome was observed: 2.1% (95% confidence interval 1.5, 2.8) for CVS and 2.3% (95% confidence interval, 1.7, 3.1) for amniocentesis. However, spontaneous losses before 20 weeks and procedure-related, indicated terminations combined were increased in the amniocentesis group (P =.07, relative risk 1.74). We found a 4-fold increase in the rate of talipes equinovarus after amniocentesis (P =.02) overall and in week 13 (P =.03, relative risk = 4.65), but data were insufficient to determine this risk in week 14. CONCLUSION: Amniocentesis at 13 weeks carries a significantly increased risk of talipes equinovarus compared with CVS and also suggests an increase in early, unintended pregnancy loss. LEVEL OF EVIDENCE: I

Abortion, Induced↗
PubMed2000

Studies of the mechanism of amniotic sac puncture-induced limb abnormalities in mice.

The principal advantage of chorionic villus sampling (cvs) over amniocentesis for the determination of the genetic constitution of the embryo is that it may be undertaken earlier in pregnancy. If carried out too early in pregnancy, it has the risk of inducing craniofacial and limb abnormalities, a condition termed the oromandibulofacial limb hypogenesis (OMFL) syndrome in genetically normal infants. It is believed that the defects observed have a vascular origin, possibly due to anoxia of tissues due to fetal blood loss or thrombus formation at the site of biopsy with distal embolization. We believe that this does not adequately explain the findings from the experimental animal literature involving amniotic sac puncture (ASP). Based on these experimental findings, we have hypothesised that (i) the defects observed following cvs may result from the consequences of oligohydramnios following the inadvertent puncturing of the amniotic sac during this procedure, and (ii) that cleft palate and the postural limb defects observed (e.g., clubfoot and clubhand) are secondary to embryonic/fetal compression. Our experimental studies shed new light on the mechanism of induction of the limb defects seen, but particularly syndactyly. Evidence of hypoperfusion of the peripheral part of the developing limb bud is observed, which interferes with apoptosis that occurs in the digital interzones, or induces an abnormal degree of cellular proliferation and/or tissue regeneration in these sites, possibly because of over-expression of critical genes involved in limb pattern specification. Cleft palate, tail abnormalities and abnormalities of sternal ossification are also observed in our model.

Amniocentesis↗
PubMed1990

Chromosome abnormalities in older women by maternal age: evaluation of regression-derived rates in chorionic villus biopsy specimens.

Maternal age-specific rates of chromosome abnormalities in women undergoing chorionic villus sampling (CVS) were evaluated. These were rates derived from regression equations of the form rate = ln(b[age] + c) where age varied from 35 to 48 years; and b and c are parameters. For Down syndrome (47, + 21), b = 0.29 and c = -15.53; for other nonmosaic abnormalities, b = 0.25 and c = -14.11; and, for all abnormalities, b = 0.27 and c = -14.22. The predicted rates per 1,000 varied, respectively, from 4.2, 4.6, and 8.8 at age 35 years to 180.0, 120.0, and 300.0 at age 48 years. The predicted numbers of abnormalities were compared with those observed in an overlapping data set reported in the literature. For 47, + 21, the ratio of observed (O) to expected (E) numbers was 54/56.4 = 0.96, suggesting that these rates are at least not grossly erroneous. For non-47, + 21 chromosome abnormalities, the ratio of O to E was 66/51.1 = 1.29. The possibility of geographic variation in rates of non-47, + 21 chromosome abnormalities cannot be dismissed. Finally, if 1) the regression derived rates are correct, 2) there is no difference in selective loss of chromosome abnormalities between younger and older mothers, and 3) the ratio of rates at ages 35 and 40 years to those in the women of all ages are the same for all abnormalities at CVS as for 47, + 21 in live births, then the proportion of all women with viable conceptuses at time of CVS who have an embryo or fetus with cytogenetic abnormality is 3.8-4.4 per 1,000 conceptuses.

Adult↗
PubMed1990

Malformations and minor anomalies in children whose mothers had prenatal diagnosis: comparison between CVS and amniocentesis.

The frequency of abortion following chorionic villus sampling (CVS) is similar to that following amniocentesis. However, there is no information on long-term effects, such as malformations in liveborn children exposed to CVS. We evaluated 189 infants whose mothers had either CVS or amniocentesis as participants in the Canadian Collaborative Randomized Trial, a prospective assessment of the safety of CVS compared with amniocentesis. The participation rate of children who could be contacted was 95%. Ninety-five of the 189 infants (50.2%) had been exposed to CVS, 87 (46%) to amniocentesis, and 7 (3.8%) to both. (The latter group was excluded from calculations.) One hundred twenty-eight (128) children had greater than or equal to one minor anomalies but no major abnormalities: 58 of 95 (60%) in the CVS and 70 of 87 (80%) in the amniocentesis group. Twenty-six children had malformations: 17 (17.8%) in the CVS and 9 (10.3%) in the amniocentesis group. Only one anomaly, Sturge-Weber dysplasia (amniocentesis group), was potentially severe and none were life-threatening. Superficial cavernous hemangiomas (strawberry nevi) were noted more frequently in children in the CVS group (12.6%) than in the amniocentesis group (3.4%), but only slightly higher than in the general public. We conclude that exposure to CVS is not associated with an increased frequency of malformations or minor anomalies in infants compared with amniocentesis although we observed a higher frequency of superficial cavernous (strawberry) hemangiomas in the children in the CVS group.

Amniocentesis↗
PubMed1991

[Evaluation of the risks of transabdominal chorionic villus sampling. 600 cases].

The authors report their experience with fine needle chorionic villus sampling carried out transabdominally. Six hundred antenatal karyotype diagnoses were made using this method. The indications were: maternal age: 509 (85%), previous chromosomal abnormalities: 57 (9.5%), parental chromosomal abnormalities: 19 (3%), X chromosome linked diseases: 9 (1.5%), others: 6 (1%). The patients were divided into two groups according as to whether the test was carried out before or after 12 weeks of amenorrhea (Group 1 and Group 2). Each group was divided into two sub-groups according to whether the amniotic membranes were broken or not. The test was carried out using a 20 gauge needle under ultrasound control with a to-and-fro movement using continuous aspiration. The success rate was 98.4%. Minor complications were rare. Contractions 9 (1.5%), spotting 4 (0.6%), small haematomas 13 (2.1%), loss of amniotic fluid 4 (0.6%). The level of unintentional abortions depended on the duration of the pregnancy and whether the amniotic cavity or not was entered. In group 1 (before or at 12 weak amenorrhea) there were 2 abortions out of 124 cases (1.6%) and if the needle entered the amniotic cavity 10 out of 57 cases (17.5%). In group 2 (after 12 weeks of amenorrhea) there was no ill effect from going into the amniotic cavity to the rest of the pregnancy. The abortion rates was 6 out of 419 (1.43%). There were no false positive or negative results.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed2006

Prenatal diagnosis for severe inherited skin disorders: 25 years' experience.

BACKGROUND: Over the last 25 years there have been major advances in methods for prenatal testing of inherited skin disorders. Since 1979, our group at the St John's Institute of Dermatology has performed 269 prenatal diagnoses, using a variety of approaches, including fetal skin biopsy (FSB), chorionic villus sampling (CVS) and preimplantation genetic diagnosis (PGD). OBJECTIVES: This study was designed to review the clinical indications, testing procedures and laboratory analyses for all prenatal tests conducted at St John's over this period. METHODS: FSBs were examined for morphological and, when relevant or feasible, immunohistochemical abnormalities. The DNA-based tests involved screening by nucleotide sequencing, restriction enzyme digests or, in a few cases, by linkage analysis. Results Of the 269 tests, 191 were FSB, 76 were CVS and two were PGD. The major indications for FSB were epidermolysis bullosa (EB) (138 cases, including 88 junctional and 48 dystrophic), ichthyoses (37 cases, including 22 tests for harlequin ichthyosis) and oculocutaneous albinism (12 cases). Of the CVS procedures, 75 were for EB (40 junctional, 35 dystrophic) and one was for the EEC (ectrodactyly, ectodermal dysplasia, clefting) syndrome. Both of the PGD procedures were for the skin fragility-ectodermal dysplasia syndrome. All tests provided accurate diagnoses and the fetal loss rate was approximately 1% for both FSB and CVS. CONCLUSIONS: The development of prenatal testing has proved to be of great benefit for individuals or couples at risk of having children with severe inherited skin disorders and, in the absence of a cure, prenatal testing along with appropriate counselling has become an important translational benefit of basic research and an integral part of clinical management.

Biopsy↗
PubMed1992

Decreasing risk of pregnancy loss following chorionic villus sampling. Elimination of transabdominal chorionic villus sampling during the ninth week of pregnancy.

Chorionic villus sampling (CVS) is a method of obtaining fetal cells in the first trimester of pregnancy for genetic analysis. The transcervical (TC) approach was the first technique to be widely used. In the National Institute of Child Health and Human Development collaborative study the absolute loss rate following CVS (the total number of spontaneous abortions and neonatal deaths following CVS) was 4%. More recently the transabdominal (TA) approach has been introduced. This study compares the loss rates for the two approaches at various gestational ages for three 6-month periods following the addition of the TA approach with each other and with the loss rates prior to the introduction of TA CVS. We found that the percentage of pregnancy losses following TA CVS during the ninth week of gestation (63-69 days) was consistently higher than for TC CVS performed at the same gestational age. The loss rate for TC CVS has steadily decreased since the introduction of TA CVS after remaining the same for the two years prior to the introduction of the TA approach. After minimizing the number of TA CVS performed during the ninth week of gestation, the overall loss rate during the most recent 6-month period has been reduced to 0.94%. We conclude that the lowest loss rate following CVS can be obtained if both the TA and TC methods are available, and that the number of TA procedures performed during the ninth week of gestation is minimized.

Abortion, Spontaneous↗
PubMed2003

Increased nuchal translucency and decreased fetomaternal transfusion after chorionic villus sampling.

OBJECTIVE: To investigate the relationship between nuchal translucency (NT) and fetomaternal transfusion (FMT) after chorionic villus sampling (CVS). METHODS: The level of FMT was determined in 272 viable, singleton pregnancies in which 10-14-week ultrasound scanning, NT measurement and CVS for fetal karyotyping had been performed. The pre-CVS NT was measured transvaginally, and the women were divided into two groups, i.e. those with NT < 2.5 mm (Group 1) or >or= 2.5 mm (Group 2). The level of FMT was determined via the maternal serum alpha-fetoprotein levels before and after CVS. FMT was analyzed in relation to the pre-CVS NT. RESULTS: Of the 272 pregnancies, 213 were in Group 1 and 59 in Group 2. The mean levels of FMT after CVS were 23.3 +/- 12.2 and 5.4 +/- 2.9 micro L in Groups 1 and 2, respectively (P < 0.01). An FMT > 100 micro L was found in 19 cases in Group 1, whereas the maximum in Group 2 was 67.2 micro L. Aneuploidies were diagnosed in 17 cases, 15 (88.2%) of them in Group 2. When the pregnancies with adverse outcome were excluded from the two groups, a higher level of FMT was observed in Subgroup 1 than in Subgroup 2 (P < 0.01). CONCLUSIONS: The mean level of FMT after CVS was significantly lower in pregnancies with an increased pre-CVS NT, a relationship observed in euploid pregnancies also. An increased pre-CVS NT seems to be inversely correlated with the FMT increase after CVS. Further studies are planned to investigate the background to this phenomenon.

Aneuploidy↗
PubMed1996

Serum parameters and nuchal translucency in first trimester screening for fetal chromosomal abnormalities.

OBJECTIVE: To assess the relation between serum parameters and nuchal translucency in pregnancies affected by fetal aneuploidy in the first trimester. DESIGN: Retrospective study of different serum parameters collected prior to chorionic villus sampling and measurement of nuchal translucency in relation to fetal aneuploidy. SETTING: Switzerland (German and Italian sector) and Bregenz, Austria. POPULATION: One thousand one hundred and fifty-one women aged 25 to 44 years at 10 to 13 weeks of gestation undergoing chorionic villus sampling, mostly for advanced maternal age. Fetal aneuploidy was found in 23 pregnancies including four cases of trisomy 21, five of trisomy 18 and one case of trisomy 13. MAIN OUTCOME MEASURE: Fetal karyotype, serum levels of free beta-hCG, pregnancy-associated plasma protein A (PAPP-A) and alpha-fetoprotein and the measurement of nuchal translucency. RESULTS: Serum PAPP-A was decreased in all common chromosomal abnormalities. Free beta-hCG levels were increased in trisomy 21 but decreased in trisomy 18, whereas alpha-fetoprotein was low in trisomy 21, 18 and other chromosomal abnormalities. Nine of twenty-three abnormal embryos had evidence of an increased nuchal translucency. Nuchal translucency, however, did not seem to be associated with any alteration in the levels of the biochemical parameters in either chromosomally normal or abnormal embryos. A low serum PAPP-A or an increased nuchal translucency was seen in two-thirds of all pregnancies with chromosomal abnormalities. CONCLUSION: A nuchal translucency > or = 3 mm and depressed serum PAPP-A levels have a good predictive value in the detection of fetal aneuploidy at 10 to 13 weeks of pregnancy. Serum free beta-hCG and alpha-fetoprotein levels may give additional information. An increased nuchal translucency was not associated with altered serum parameters. This would allow these different markers to be used in combination.

Adult↗
PubMed1993

Uniparental disomy for chromosome 16 in humans.

The association between chromosomal mosaicism observed on chorionic villus sampling (CVS) and poor pregnancy outcome has been well documented. CVS mosaicism usually represents abnormal cell lines confined to the placenta and often involves chromosomal trisomy. Such confined placental mosaicism (CPM) may occur when there is complete dichotomy between a trisomic karyotype in the placenta and a normal diploid fetus or when both diploid and trisomic components are present within the placenta. Gestations involving pure or significant trisomy in placental lineages associated with a diploid fetal karyotype probably result from a trisomic zygote which has lost one copy of the trisomic chromosome in the embryonic progenitor cells during cleavage. Uniparental disomy would be expected to occur in one-third of such cases. Trisomy of chromosome 7, 9, 15, or 16 is most common among the gestations with these dichotomic CPMs. Nine pregnancies with trisomy 16 confined to the placenta were prenatally diagnosed. Pregnancy outcome, levels of trisomic cells in term placentas, and fetal uniparental disomy were studied. Intrauterine growth retardation (IUGR), low birthweight, or fetal death was observed in six of these pregnancies and correlated with high levels of trisomic cells in the term placentas. Four of the five cases of IUGR or fetal death showed fetal uniparental disomy for chromosome 16. One of the infants with maternal uniparental disomy 16 had a significant malformation (imperforate anus). All infants with normal intrauterine growth showed term placentas with low levels of trisomic cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2002

Prolonged culture of normal chorionic villus cells yields ICF syndrome-like chromatin decondensation and rearrangements.

Untreated cultures from normal chorionic villus (CV) or amniotic fluid-derived (AF) samples displayed dramatic cell passage-dependent increases in aberrations in the juxtacentromeric heterochromatin of chromosomes 1 or 16 (1qh or 16qh). They showed negligible levels of chromosomal aberrations in primary culture and no other consistent chromosomal abnormality at any passage. By passage 8 or 9, 82 +/- 7% of the CV metaphases from all eight studied samples exhibited 1qh or 16qh decondensation and 25 +/- 16% had rearrangements in these regions. All six analyzed late-passage AF cultures displayed this regional decondensation and recombination in 54 +/- 16 and 3 +/- 3% of the metaphases, respectively. Late-passage skin fibroblasts did not show these aberrations. The chromosomal anomalies resembled those diagnostic for the ICF syndrome (immunodeficiency, centromeric region instability, and facial anomalies). ICF patients have constitutive hypomethylation at satellite 2 DNA (Sat2) in 1qh and 16qh, generally as the result of mutations in the DNA methyltransferase gene DNMT3B. At early and late passages, CV DNA was hypomethylated and AF DNA was hypermethylated both globally and at Sat2. DNMT1, DNMT3A, or DNMT3B RNA levels did not differ significantly between CV and AF cultures or late and early passages. The high degree of methylation of Sat2 in late-passage AF cells indicates that hypomethylation of this repeat is not necessary for 1qh decondensation. Sat2 hypomethylation may nonetheless favor 1qh and 16qh anomalies because CV cultures, with their Sat2 hypomethylation, displayed 1qh and 16qh decondensation and rearrangements at significantly lower passage numbers than did AF cultures. Also, CV cultures had much higher ratios of ICF-like rearrangements to heterochromatin decondensation in chromosomes 1 and 16. These cultures may serve as models to help elucidate the biological consequences of cancer-associated satellite DNA hypomethylation.

Amniotic Fluid↗
PubMed2005

Trisomies and other chromosome abnormalities detected after positive sonographic findings.

OBJECTIVE: To evaluate the rate of trisomies and other chromosome abnormalities after positive ultrasound findings in thefirst and second trimester of pregnancy. STUDY DESIGN: The study investigated chromosome abnormalities detected in cases with prior abnormal ultrasoundfindings. During a 10-year period there were 1907 invasive interventions carried out with the purpose of chromosome analysis. The intervention was genetic amniocentesis in 1619 cases and chorionic villus sampling in 288. RESULTS: Karyotyping revealed 103 cases (5.4%) of chromosome abnormalities. Abnormalities with subcutaneous edema were examined: abnormal karyotype was found in 20% of cases with nonimmune hydrops, 48.1% of cases with cystic hygroma and 53.8% of cases with nonimmune hydrops and cystic hygroma together, 8.3% of cases with nuchal edema in the first trimester and 5.5% in the second trimester. The incidence of chromosome abnormalities in cases of cerebral anomalies was 6.3% of cases with ventricular dilatation, 3.6% of cases with choroid plexus cysts and 15.9% of cases with other cranial anomalies. Regarding abnormalities of the heart, isolated echogenic intracardiac focus and ventricular septal defects were not associated with chromosome abnormality, but, in conjunction with other positive ultrasound findings, the incidence of chromosome abnormalities was 7.9% and 26.7%, respectively. Other anomalies of the heart and large blood vessels showed an abnormal karyotype incidence of 18.2%. In cases of unilateral pyelectasis unassociated with other anomalies, the incidence of chromosome abnormalities was 1%. In cases of bilateral pyelectasis or pyelectasis associated with other anomalies, the incidence was 3%. In terms of anomalies of the abdominal wall and abdomen, the incidence of association with chromosome abnormalities was 9.5% in cases of omphalocele, 11.8% in cases of duodenal atresia and 5.7% in cases of echogenic bowel. In cases of short femur and humerus the rate of abnormal karyotypes was 16%. CONCLUSION: Ultrasound plays an important role in prenatal diagnosis. In cases of positive ultrasound findings, karyotyping is reasonable.

Amniocentesis↗
PubMed2003

Prospective ranking of the sonographic markers for aneuploidy: data of 2143 prenatal cytogenetic diagnoses referred for abnormalities on ultrasound.

OBJECTIVE: To design a scheme to rank sonographic anomalies as indicators of aneuploidy and record the distribution of data from 2143 prenatal amniotic fluid/chorionic villous sample diagnoses referred for karyotyping because of fetal anomalies detected with ultrasound. METHODS: In all cases the records of sonographic anomalies were obtained prior to karyotyping. A cascade of seven prospective categories of ultrasound anomalies was chosen and the data were included in the highest compatible sonography category. The categories were in descending order: (I) combined central nervous system (CNS)/cranial shape and cardiac anomalies (excluding spina bifida and anencephaly); (II) key anomaly present (exomphalos/ intrauterine growth restriction/duodenal atresia/cystic hygroma/fetal hydrops/talipes--with other multiple anomalies); (III) CNS +/- other abnormality (excluding choroid plexus cyst, spina bifida, anencephaly); (IVa) increased nuchal translucency--first trimester +/- other abnormality; (IVb) increased nuchal thickening--second trimester +/- other abnormality; (V) cardiac anomaly +/- other abnormality; (VI) other markers of aneuploidy (pyelectasis/two vessel cord/echogenic bowel/short femur); and (VII) other (mostly isolated) malformations. RESULTS: There were 412/2143 (19.2%) chromosome abnormalities detected in this sonographically abnormal group. Overall, the prevalence of aneuploidy significantly ranged from 51 to 3% according to the above I-VII ultrasound categories and from approximately 1-80% for individual ultrasound anomalies. Likelihood ratios were derived for many ultrasound anomalies for several aneuploidy groups: trisomies of 13; 18; and 21; 45,X and 45,X mosaics; triploidy; other autosomal duplications and/or deletions; and other (than 45,X) sex chromosomal aneuploidies. CONCLUSION: It is suggested this data could be used to assist pre-procedural counselling of patients after the ultrasound scan in tertiary referral centres for prenatal cytogenetic diagnosis.

Abnormalities, Multiple↗