Echogenic intracardiac focus in 2nd-trimester fetuses with trisomy 21: usefulness as a US marker.

PURPOSE: To determine whether there is a relationship between the presence of an echogenic intracardiac focus in 2nd-trimester fetuses and trisomy 21 (Down syndrome). MATERIALS AND METHODS: A complete genetic ultrasonographic (US) scan was obtained in 3,303 consecutive fetuses with an estimated gestational age of 14.0-24.0 weeks (mean +/- SD, 17.1 weeks +/- 1.75). US was performed in a prospective fashion without any knowledge of karyotype and included assessment of any potential echogenic intracardiac focus (ie, calcified papillary muscle). Karyotypes were obtained in all fetuses. Maternal ages ranged from 13.0 to 47.4 years (mean, 35.1 years +/- 5.1). The prevalence of Down syndrome in this population was 1.6% (53 of 3,303 fetuses). RESULTS: An echogenic intracardiac focus was seen in 147 of the 3,192 karyotypically normal fetuses (4.6%) and 16 of the 53 fetuses with trisomy 21 (30%). The positive predictive value (PPV) of an echogenic intracardiac focus in this high-risk population was 9.8%; sensitivity, 30%; specificity, 95%; likelihood ratio, 6.6; and relative risk (RR), 8.2 (P <.001). For a sonographically isolated echogenic intracardiac focus, the PPV was 3.7%; sensitivity, 19%; specificity, 95%; likelihood ratio, 4.2; and RR, 4.8 (P =.002). CONCLUSION: A sonographically isolated echogenic intracardiac focus (no other anomalies or markers noted on a complete genetic sonogram) was associated in our high-risk population with a 4.8-fold (95% CI: 1.8, 12.5) increase in RR for trisomy 21 (P =.002).

The "genetic sonogram": comparison of the index scoring system with the age-adjusted US risk assessment.

PURPOSE: To compare two ultrasonographic (US) methods for prenatal detection of fetal Down syndrome. MATERIALS AND METHODS: Genetic amniocentesis was successfully performed in 3,303 consecutive women with high-risk pregnancies (mean gestational age, 17.1 weeks). All patients underwent a complete "genetic US" examination prospectively. Risk was assessed by using (a) various modifications of the index scoring system (ISS) and (b) the age-adjusted US risk assessment (AAURA). RESULTS: The prevalence of Down syndrome in this population was 1.6% (53 of 3,303). By using a threshold of at least 2 points to detect trisomy 21, the best ISS had a sensitivity of 45.3%, false-positive rate of 4.9%, likelihood ratio of 9.3, and positive predictive value in the high-risk population in this study of 13.3%. Lowering the threshold to 1 point increased the sensitivity to 60.4% but increased the false-positive rate to 15.8%. Adding points for age increased the sensitivity to 67.9% but increased the false-positive rate to 24.3%. Results of using AAURA to detect trisomy 21 were nearly identical, with a sensitivity of 43.4% and false-positive rate of 4.9% at a 1 in 36 risk threshold and a sensitivity of 69.8% and false-positive rate of 26.1% at a 1 in 200 threshold. Trisomies 18 and 13 were detected with sensitivities of 80.0% and 100.0%, respectively, with either system. CONCLUSION: The modified ISS and AAURA are equivalent in screening for Down syndrome, with detection of approximately half of all trisomy 21 fetuses at a 5% false-positive rate.

Cerebellar and frontal lobe hypoplasia in fetuses with trisomy 21: usefulness as combined US markers.

PURPOSE: To confirm that cerebellar hypoplasia is ultrasonographically recognizable in second-trimester fetuses with Down syndrome and determine whether the combination of frontal lobe shortening and cerebellar hypoplasia is superior to either measurement alone as a marker of this abnormality. MATERIALS AND METHODS: The frontothalamic distance (FTD) and transcerebellar diameter (TCD) were measured in 52 middle-trimester fetuses with euploid karyotypes and in 52 fetuses with Down syndrome. Receiver operating characteristic (ROC) curves were constructed with various thresholds for observed-to-expected ratios (O/Es) of the FTD, TCD, and average of these two parameters. RESULTS: The area under the average ROC curve, 0.80, was greater than that for either the FTD alone (0.75) or the TCD alone (0.76). At a 6% false-positive rate, the sensitivity for the detection of Down syndrome obtained with the average parameter was 34% better than that obtained with only the FTD and 12% better than that obtained with only the TCD. With an O/E threshold of 0.92 for the average parameter, an odds ratio of 16.3 and positive predictive value of 12.7% in the high-risk population were achieved. CONCLUSION: Although both measurements are individually statistically significant, the combination of TCD and FTD measurements may be superior to the use of either parameter alone as a marker of trisomy 21.

Frontal lobe shortening in second-trimester fetuses with trisomy 21: usefulness as a US marker.

PURPOSE: To determine whether the frontal lobe is disproportionately smaller than normal in second-trimester fetuses with Down syndrome by using prenatal ultrasonographic (US) measurements of the frontothalamic distance (FTD). MATERIALS AND METHODS: The FTD, measured from the inner table of the frontal bone to the posterior margin of the thalamus, was measured in 43 fetuses (mean gestational age, 17.2 weeks +/- 1.3 [standard deviation]; range, 15.0-20.4 weeks) with chromosomally proved trisomy 21 and in 160 chromosomally normal fetuses (mean gestational age, 17.1 weeks +/- 1.5; range, 14.5-22.5 weeks). Other cranial biometric ratios also were calculated. RESULTS: The FTD was best predicted from the estimated gestational age (EGA) in the euploid population with the quadratic equation FTD = -0.0120 x EGA2 + 0.6917 x EGA - 5.2349 (R2 = .731) or from the biparietal diameter (BPD) with the linear equation FTD = 0.6837 x BPD + 0.5525 (R2 = .731). If an observed-to-expected ratio of 0.84 is used as a cutoff sign to screen for trisomy 21, a sensitivity of 16%, specificity of 97%, odds ratio of 6.03 (95% confidence interval, 1.81, 20.1), and relative risk of 5.98 are achieved. CONCLUSION: The frontal lobe is statistically significantly smaller in fetuses with trisomy 21. US measurement of the FTD may prove to be a useful adjunctive screening tool if used with other markers for Down syndrome.

Amniotic fluid alpha-fetoprotein determination at the time of genetic amniocentesis: has it outlived its usefulness?

The purpose of this retrospective study was to evaluate the utility of routine measurement of amniotic fluid alpha-fetoprotein levels at the time of second trimester genetic amniocentesis (mean gestational age, 17.3 weeks +/- 2.5 weeks standard deviation; median, 16.8 weeks; range, 15 to 22 weeks). During the study period 7174 patients underwent second trimester genetic amniocentesis. Outcome data were available in all cases. In 79 (1.1%) cases the amniotic fluid alpha-fetoprotein level was > or = 2.0 multiples of the median. Thirty-three of the 79 (42%) patients had normal ultrasonograms, and in 31 of 33 (94%) the amniotic fluid alpha-fetoprotein level was between 2.0 and 3.0 multiples of the median. Forty-six of the 79 (58%) patients had abnormal ultrasonographic findings, and of these, 82% were neural tube defects, abdominal wall defects, or cystic hygromas. Acetylcholinesterase was positive in 37 cases, all of which had abnormal ultrasonographic findings. None of the fetuses with negative findings on sonographic screening had detectable abnormalities at birth. In this study, with over 7000 patients, amniotic fluid alpha-fetoprotein and acetylcholinesterase levels did not increase the detection of fetal abnormalities. On the basis of these results, routine measurement of amniotic fluid alpha-fetoprotein level at the time of routine genetic amniocentesis (15 to 22 weeks) does not appear justified.

Isolated fetal choroid plexus cysts and karyotype analysis: is it necessary?

The purpose of this study was to evaluate the risk of fetal aneuploidy in the presence of isolated choroid plexus cysts and to evaluate the results obtained from our institution and those reported previously in the English literature. All patients with fetal choroid plexus cysts on prenatal ultrasonography were offered genetic counseling and amniocentesis for fetal karyotyping. Seven of 274 fetuses, 2.6% (95% confidence interval = 1.0 to 5.2%), with isolated choroid plexus cysts were aneuploid. Literature analysis located 23 other reports of 1537 fetuses with isolated choroid plexus cysts; 26 were karyotypically abnormal, 1.7% (95% confidence interval = 1.0 to 2.4%). When evaluating only those patients whose indication for amniocentesis was choroid plexus cysts (i.e., eliminating those patients with advanced maternal age or abnormal serum screening) the risk of having a fetus with trisomy 18 changed little, 1.9% (95% confidence interval = 0.4 to 5.5%). Our data, combined with those of the literature, suggest that the risk of finding an abnormal fetal karyotype in the presence of isolated choroid plexus cysts is at least 1% and may be as high as 2.4%. On the basis of these results, genetic counseling and prenatal diagnosis should be offered to these patients.

Inconsistencies in pedigree symbols in human genetics publications: a need for standardization.

To determine consistency in usage of pedigree symbols by genetics professionals, we reviewed pedigrees printed in 10 human genetic and medical journals and 24 medical genetics textbooks. We found no consistent symbolization for common situations such as pregnancy, spontaneous abortion, death, or test results. Inconsistency in pedigree design can create difficulties in the interpretation of family studies and detract from the pedigree's basic strength of simple and accurate communication of medical information. We recommend the development of standard pedigree symbols, and their incorporation into genetic publications, professional genetics training programs, pedigree software programs, and genetic board examinations.

Recommendations for standardized human pedigree nomenclature. Pedigree Standardization Task Force of the National Society of Genetic Counselors.

The construction of an accurate family pedigree is a fundamental component of a clinical genetic evaluation and of human genetic research. Previous surveys of genetic counselors and human genetic publications have demonstrated significant inconsistencies in the usage of common pedigree symbols representing situations such as pregnancy, termination of pregnancy, miscarriage, and adoption, as well as less common scenarios such as pregnancies conceived through assisted reproductive technologies. The Pedigree Standardization Task Force (PSTF) was organized through the Professional Issues Committee of the National Society of Genetic Counselors, to establish recommendations for universal standards in human pedigree nomenclature. Nomenclature was chosen based on current usage, consistency among symbols, computer compatibility, and the adaptability of symbols to reflect the rapid technical advances in human genetics. Preliminary recommendations were presented for review at three national meetings of human genetic professionals and sent to > 100 human genetic professionals for review. On the basis of this review process, the recommendations of the PSTF for standardized human pedigree nomenclature are presented here. By incorporating these recommendations into medical genetics professional training programs, board examinations, genetic publications, and pedigree software, the adoption of uniform pedigree nomenclature can begin. Usage of standardized pedigree nomenclature will reduce the chances for incorrect interpretation of patient and family medical and genetic information. It may also improve the quality of patient care provided by genetic professionals and facilitate communication between researchers involved with genetic family studies.

Recommendations for standardized human pedigree nomenclature.

The construction of an accurate family pedigree is a fundamental component of a clinical genetic evaluation and of human genetic research. Previous surveys of genetic counselors and human genetic publications have demonstrated significant inconsistencies in the usage of common pedigree symbols representing situations such as pregnancy, termination of pregnancy, miscarriage, and adoption, as well as less common scenarios such as pregnancies conceived through assisted reproductive technologies. The Pedigree Standardization Task Force (PSTF) was organized through the Professional Issues Committee of the National Society of Genetic Counselors, to establish recommendations for universal standards in human pedigree nomenclature. Nomenclature was chosen based on current usage, consistency among symbols, computer compatibility, and the adaptability of symbols to reflect the rapid technical advances in human genetics. Preliminary recommendations were presented for review at three national meetings of human genetic professionals and sent to >100 human genetic professionals for review. On the basis of this review process, the recommendations of the PSTF for standardized human pedigree nomenclature are presented here. By incorporating these recommendations into medical genetics professional training programs, board examinations, genetic publications, and pedigree software, the adoption of uniform pedigree nomenclature can begin. Usage of standardized pedigree nomenclature will reduce the chances for incorrect interpretation of patient and family medical and genetic information. It may also improve the quality of patient care provided by genetic professionals and facilitate communication between researchers involved with genetic family studies.

Fetal t(5p;21q) misdiagnosed as monosomy 21: a plea for in situ hybridization studies.

We report a case of 45,XY,-5,-21,+der (5) t(5;21) (p13 or p14;q11.2 or q21) that was prenatally misdiagnosed as complete monosomy 21 and terminated at 24 weeks of gestation. Subsequent fluorescence in situ hybridization studies with a chromosome 21 painting probe documented the cryptic unbalanced translocation.

The need for developing standardized family pedigree nomenclature.

To assess the variation in usage of symbols used in recording a genetic family history, full members of the National Society of Genetic Counselors were surveyed by questionnaire. The questionnaire return rate was 55.3% and genetic counselors from a broad range of clinical experience, genetic counseling training programs and geographic regions responded. There was striking variation in symbols used for recording routine medical information in a genetic family history (i.e., pregnancy, spontaneous abortion, termination of pregnancy). There was even less consensus in recording situations representing new reproductive technologies (i.e., artificial insemination by donor semen, donor ovum, surrogate motherhood). The results of this survey document the need for developing standardized nomenclature in recording genetic family histories as a quality assurance measure in the delivery of genetic services. Such standardization will reduce the chance of incorrect interpretation of patient and family medical and genetic information.

Duplication (6q) syndrome diagnosed in utero.

We report on a case of partial duplication 6q detected ultrasonographically. The clinical picture noted in utero is consistent with the adult phenotype previously reported in the literature.

Assessment of ferrocytochrome C oxidation by hydrogen peroxide.

The reduction of ferricytochrome C is commonly employed for the quantitation of O2-.H2O2 arising from the dismutation of O2- is capable of oxidizing ferrocytochrome C. In order to assess whether this may interfere with O2- quantitation, the amount of H2O2 required for the oxidation of ferrocytochrome C was determined. While H2O2 concentrations below 10(-5) M were ineffective, one half of the reduced cytochrome was oxidized by 5 x 10(-5) M H2O2 within 15 min. H2O2 in the concentration range at which ferrocytochrome C is oxidized is generated upon interaction of hypoxanthine with xanthine oxidase and upon stimulation of human polymorphonuclear neutrophilic granulocytes by phorbol myristate acetate or the phagocytosis of opsonized zymosan. It is suggested that O2- quantitation by cytochrome C reduction is routinely performed in the presence of catalase.

Diagnosis of polyhydramnios in early gestation: indication for prenatal diagnosis?

Previously published reports have indicated that idiopathic polyhydramnios may be associated with trisomies 18 and 21 and that chromosomal analysis is indicated. Furthermore, the natural history and fetal outcome of polyhydramnios diagnosed in early gestation have not been well delineated. We identified 138 pregnancies with polyhydramnios prior to 26 weeks' gestation. Of 131 complete cases, 21 were diagnosed as severe, 18 as moderate, and 92 as mild polyhydramnios. Congenital abnormalities were noted in 18 of 21 severe cases (86 per cent). Two of the remaining three cases were twin-to-twin transfusion. Thirteen of 18 cases with moderate polyhydramnios (72 per cent) were associated with anomalies; six of the remaining cases were twin-to-twin transfusion. Sixteen of 92 cases of mild polyhydramnios (17 per cent) were associated with congenital abnormalities. In 69 of 76 cases of mild hydramnios not associated with anomalies (91 per cent), the hydramnios resolved prior to delivery. Only 2 of 16 (13 per cent) associated with anomalies resolved. In 4 of 5 cases (80 per cent) with moderate hydramnios and no anomalies, the amniotic fluid volume was normal on subsequent ultrasound. No case of moderate polyhydramnios associated with anomalies or maternal conditions nor any case of severe polyhydramnios resolved. There were seven cases of chromosomal abnormalities in this series; all were associated with sonographic findings in addition to the presence of polyhydramnios. On the basis of these data, we doubt the benefit of amniocentesis following the early diagnosis of idiopathic polyhydramnios in the absence of other ultrasound findings.

Adherence-induced enhancement of the oxidative burst of human neutrophilic granulocytes: effects of the surface coat and of divalent cations.

Neutrophilic granulocytes are capable of adhering to biological or artificial surfaces. In addition to specific interactions between adherence molecules on the cell surface and corresponding structures on other cells or matrix proteins like fibronection or collagen there appeared to be non-specific attachment as well. Adherence augmentation induced by stimulation with chemotactic factors or cytokines was an active process which did not proceed at 4 degrees C and after removal of divalent cations from the medium. Adherence acted as a priming stimulus increasing the amount of superoxide anion and hydrogen peroxide produced in response to stimulation by certain chemotactic factors and cytokines. Adherence priming like priming by GM-CSF was strongly suppressed by chelation of intracellular Ca2+ ions. The two priming mechanisms differed, however, in their requirement for divalent cations in the external medium: whereas Mg2+ suppressed GM-CSF priming, it synergised with Ca2+ in the adherence-augmented oxidative burst.

Inhibition of chemotactic migration of human neutrophilic granulocytes by recombinant human granulocyte-macrophage colony-stimulating factor.

Human recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) was analysed for effects on the migration of human neutrophilic granulocytes by the Boyden chamber assay. At concentrations ranging from 0.1 to 10,000 U/ml (or 10(-12) to 10-mol/l) GM-CSF had neither chemokinetic nor chemotactic activity. When added to the cells in the upper compartment of the chamber GM-CSF dose-dependently inhibited the chemotactic migration towards the tripeptide f-Met-Leu-Phe and the complement split product C5a. Chemotaxis towards f-Met-Leu-Phe was inhibited more efficiently by GM-CSF than C5a-induced migration.

Production of superoxide anion and hydrogen peroxide by human neutrophilic granulocytes during chemotactic migration towards f-Met-Leu-Phe, C5a, leukotriene B4, monocyte-derived chemotaxin/IL-8 and platelet-activating factor.

During the chemotactic migration of human neutrophilic granulocytes towards the chemotactic factors f-Met-Leu-Phe, C5a, leukotriene B4 (LTB4), monocyte-derived chemotaxin (MOC/IL-8) and platelet-activating factor (PAF) in Boyden chambers, the production of superoxide anion and hydrogen peroxide was measured by superoxide dismutase-inhibitable cytochrome C reduction and oxidation of p-OH-phenylacetic acid, respectively. With the exception of 10(-6) M PAF, none of the factors at optimal chemotactic concentrations induced the production of O2- or H2O2 in amounts significantly different from neutrophilic granulocytes migrating at random. At 20-50 times the optimal chemotactic concentration some O2- and H2O2 production was observed with f-Met-Leu-Phe, C5a and LTB4, but not with MOC/IL-8. Superoxide dismutase, catalase or a combination of the two added to both compartments of the Boyden chambers did not affect the random or chemotactic migration towards any of the chemotactic factors. The results suggest that chemotactic migration and the production of reactive oxygen metabolites by human neutrophilic granulocytes are unrelated events.

Sonography of placental abnormalities and oligohydramnios in women with elevated alpha-fetoprotein levels: comparison with control subjects.

To evaluate the relationship of placental and amniotic fluid findings to elevated maternal serum alpha-fetoprotein (MS-AFP) levels, we compared sonograms made between 18 and 24 weeks gestational age in 76 women with elevated MS-AFP levels with sonograms of a control group. Patients with fetal malformations, incorrect dates, twins, or lack of follow-up were excluded. Overall, 27 (36%) of 76 patients with elevated MS-AFP levels had placental or amniotic fluid abnormalities compared with only three (3%) of 87 control subjects. Significant differences (p less than .01) were noted in the frequency of periplacental hemorrhage (9% vs 0%), intraplacental sonolucencies greater than or equal to 1.5 cm in diameter (18% vs 3%) and moderate or severe oligohydramnios (17% vs 0%). More patients with elevated MS-AFP levels had placenta previa (4%) or placental thickness greater than or equal to 3.5 cm (12%) than did those in the control group (1% and 5%, respectively), although these differences did not reach statistical significance. Seven (26%) of the 27 patients had more than one abnormality. We conclude that placental and/or amniotic fluid abnormalities are frequently shown on sonograms in women who are examined because of elevated MS-AFP levels.

Stimulation of human neutrophilic granulocytes by two monocyte-derived cytokines.

Human monocytes upon stimulation with bacterial lipopolysaccharide release two cytokines which modulate the functions of neutrophilic granulocytes (PMN), a monocyte-derived chemotaxin (MOC) and tumor necrosis factor (TNF). Both cytokines stimulated the adherence of PMN on protein-coated nylon-fibers. Whereas MOC is one of the four most potent chemoattractants known, TNF was a most powerful inhibitor of PMN chemotactic migration towards several chemotactic factors including MOC. Neither cytokine stimulated the release of superoxide anion (O2-) or hydrogen peroxide (H2O2) from PMN in suspension. However, TNF, but not MOC, caused the release of considerable amounts of H2O2 and O2- from PMN attached to nylon fibers. The two cytokines have similar effects on the adherence, opposing effects on chemotactic migration and different effects on the oxidative burst of PMN.

Modulation of human neutrophilic granulocyte functions by recombinant human tumor necrosis factor and recombinant human lymphotoxin. Promotion of adherence, inhibition of chemotactic migration and superoxide anion release from adherent cells.

Recombinant human tumor necrosis factor (TNF) and recombinant human lymphotoxin (LT) were analyzed for their effects on inflammation-related functions of human polymorphonuclear neutrophilic granulocytes (PMN) in vitro, TNF at a concentration of 10 U/ml (corresponding to 10(-11) mol/l) enhanced PMN adherence to nylon fibres. It strongly inhibited the chemotactic migration of PMN in the Boyden chamber assay towards the chemotactic tripeptide formyl-methionyl-leucyl-phenylalanine (FMLP), C5a, LTB4 and a monocyte-derived chemotaxin (MOC) without affecting random migration and without being chemotactic itself. It did not stimulate superoxide anion (-O2.) production of PMN in suspension. However, it induced considerable -O2. release from PMN that had become adherent on nylon fibres. All these effects were abrogated by prior incubation of the cytokine with polyclonal and monoclonal antibodies against TNF. LT concentrations of 1,000 U/ml or higher were required to observe a moderate inhibition of chemotactic migration towards the above chemotactic factors and to elicit some -O2. production from nylon fibre-adherent PMN. LT did not increase the adherence of PMN to nylon fibres and it was not chemotactic. The results indicate that TNF is a potent modulator of PMN functions.