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Genetic origin and proportion of basal plate surface-lining cells in normal and abnormal pregnancies.

The human placenta is a transient organ, the villous surface of which is in direct contact with the maternal circulation during pregnancy. Thus, the syncytiotrophoblast and the basal plate-lining cells are considered continuous with the endothelial layer of the maternal vasculature. Two types of cells are found on the surface of the basal plate: trophoblasts (of fetal origin) and endothelial cells of putative maternal origin. Histologic abnormalities have been described in the basal plate of the placenta obtained from patients with preeclampsia and intrauterine growth restriction. Moreover, endothelial cell dysfunction and intravascular inflammation are key features of preeclampsia. The objectives of this study were to: (1) determine the origin of the endothelial cells located in the basal plate surface of the placenta (from male fetuses); and (2) analyze the relative proportion of the intervillous surface of the basal plate occupied by trophoblasts and endothelial cells. Immunohistochemistry and morphometry were performed in placentas from women in the following clinical groups: (1) normal-term pregnancies (n = 15); (2) severe preeclampsia at term (n = 15); (3) small-for-gestational-age (SGA) neonates delivered at term (n = 15); (4) preterm deliveries (<37 weeks) without inflammation (n = 5); and (5) preterm preeclampsia (n = 5). Laser capture microdissection and polymerase chain reaction were used to determine the allelic pattern of the amelogenin gene of the endothelial cells on the intervillous surface of the basal plate. Our results showed that: (1) the endothelial cells lining the basal plate in placentas of male fetuses were uniformly of maternal origin; and (2) in placentas from uncomplicated pregnancies, the median proportion of trophoblasts and endothelial cells covering the surface of the basal plate were 27.7% and 46.5%, respectively. The remaining area of the intervillous surface of the basal plate was composed of fibrin and anchoring villi. Of interest, placentas from women who delivered an SGA neonate had a higher proportion of trophoblasts and a lower proportion of endothelial cells lining the basal plate than those from normal pregnancies (P < .05). The same tendency was observed in placentas from patients with preeclampsia. This study demonstrates that endothelial cells of maternal origin cover the intervillous surface of the basal plate of the placenta, along with trophoblasts of fetal origin. The proportion of this surface lined by trophoblasts is greater in placentas from SGA and preeclampsia than in normal pregnancy. We propose that this change reflects a compensatory mechanism whereby the basal plate surface covered by injured endothelial cells is replaced by trophoblasts or results from a failure of trophoblastic involution in abnormal pregnancies. Our observations also suggest that the lining of the basal plate can provide information about the pathology of endothelial cells in complications of pregnancy.

Adolescent↗

Long-term efficacy of subendocardial resection in refractory ventricular tachycardia: relationship to site of arrhythmia origin.

Subendocardial resection is performed in patients with ventricular tachycardia (VT), but its efficacy as related to the site of origin of VT is problematic. We analyzed the efficacy of subendocardial resection in 24 patients with coronary artery disease and VT. All patients underwent preoperative and intraoperative mapping before subendocardial resection. Postoperative electrophysiologic studies were performed in the drug-free state 7 to 14 days after subendocardial resection. Group 1 (n = 14) had anterior, septal, or lateral sites of origin, and Group 2 (n = 10) had inferior or posterior sites of origin. Localization of presystolic electrical activity during VT by preoperative and intraoperative mapping was comparable in both groups (100%). Resectability of the site of origin was higher in Group 1. Induction of VT during a postoperative electrophysiological study was higher in Group 2. Perioperative mortality was comparable. Postoperative antiarrhythmic therapy was instituted more frequently in Group 2. Actuarial survival analysis showed improved patient survival at one year after subendocardial resection for both groups. The efficacy of subendocardial resection is related to site of origin of VT: Subendocardial resection is less efficacious in VT with inferior or posterior sites of origin because of nonresectability of the arrhythmogenic area.

Adolescent↗

The convergent validity of the Phobia Origins Questionnaire (POQ): a review of the evidence.

The Phobic Origins Questionnaire (POQ) [Ost, L.-G. & Hugdahl, K. (1981). Acquisition of phobias and anxiety response patterns in clinical patients. Behaviour Research and Therapy, 19, 439-447.] is the most commonly cited instrument for determining the origins of phobic anxiety and data obtained using this instrument strongly support the role of conditioning in the acquisition of fear reactions. The construct validity of the POQ in assessing episodes of conditioning has been questioned [e.g. Menzies, R. G. & Clarke, J. C. (1994). Retrospective studies of the origins of phobias: a review. Anxiety, Stress and Coping, 7, 305-318.] This paper examined the convergent validity of the POQ by comparing origins' classifications based on the POQ to classifications based on alternative instruments. The convergent validity of the POQ was found to be extremely poor. The POQ was consistently associated with a much greater likelihood of classifying the origin of fear reactions as due to direct conditioning episodes than was found using alternative instruments. The findings question the usefulness of the POQ in examining the origins of phobic anxiety.

Conditioning, Psychological↗

The functional origin of bacteriophage f1 DNA replication. Its signals and domains.

The origin of DNA replication of bacteriophage f1 functions as a signal, not only for initiation of viral strand synthesis, but also for its termination. Viral (plus) strand synthesis initiates and terminates at a specific site (plus origin) that is recognized and nicked by the viral gene II protein. Mutational analysis of the 5' side (upstream) of the origin of plus strand replication of phage f1 led us to postulate the existence of a set of overlapping functional domains. These included ones for strand nicking, and initiation and termination of DNA synthesis. Mutational analysis of the 3' side (downstream) of the origin has verified the existence of these domains and determined their extent. The results indicate that the f1 "functional origin" can be divided into two domains: (1) a "core region", about 40 nucleotides long, that is absolutely required for plus strand synthesis and contains three distinct but partially overlapping signals, (a) the gene II protein recognition sequence, which is necessary both for plus strand initiation and termination, (b) the termination signal, which extends for eight more nucleotides on the 5' side of the gene II protein recognition sequence, (c) the initiation signal that extends for about ten more nucleotides on the 3' side of the gene II protein recognition sequence; (2) a "secondary region", 100 nucleotides long, required exclusively for plus strand initiation. Disruption of the secondary region does not completely abolish the functionality of the f1 origin but does drastically reduce it (1% residual biological activity). We discuss a possible explanation of the fact that this region can be interrupted (e.g. f1, M13 cloning vectors) by large insertions of foreign DNA without significantly affecting replication.

Base Sequence↗

Metastatic adenocarcinoma of unknown primary origin.

Adenocarcinomas account for up to 60% of all metastatic neoplasms of unknown primary origin. In general, adenocarcinomas are the most difficult metastatic tumor to accurately identify the primary site. Some metastatic adenocarcinomas have distinctive histological features that allow for their site determination (eg, colonic adenocarcinoma, bronchioloalveolar cell carcinoma), although the majority of metastatic adenocarcinomas have histological features that are not distinctive enough to allow for a specific diagnosis of their origin. For this reason, electron microscopy and immunohistochemistry have been used to help identify the exact type (origin) of metastatic adenocarcinomas. Relatively specific ultrastructural features used to diagnose metastatic adenocarcinomas of unknown primary origin include tubular myelin, intranuclear surfactant apoprotein tubular inclusions, Clara cell granules, uniform short microvilli with filamentous cores and core rootlets, Langerhans cells associated with neoplastic cells, cytoplasmic hyaline globules, lipid droplets, glycogen, and cytoplasmic crystals. Only a few of these ultrastructural features are absolutely specific. Relatively specific immunohistochemical tests used to diagnose metastatic adenocarcinomas of unknown primary origin include prostate-specific antigen, thyroglobulin, estrogen and progesterone receptor proteins, thyroid transcription factor-I, and surfactant apoproteins. Of these, prostate-specific antigen and thyroglobulin are the most specific. The purpose of this article is to discuss the use of electron microscopy and immunohistochemistry in the site-specific diagnosis of metastatic adenocarcinomas of unknown primary origin.

Adenocarcinoma↗

Anomalous origin of coronary arteries and risk of sudden death: a study based on an autopsy population of congenital heart disease.

Coronary arteries anomalies may be part of complex congenital malformations of the heart or be an isolated defect. In our anatomic collection of congenital heart disease, an isolated anomalous origin of coronary arteries was observed in 27 of 1,200 specimens (2.2%): left coronary artery from pulmonary trunk in five, origin from the wrong aortic sinus in 12 (both right and left coronary artery from the right sinus in four and from the left sinus in seven, left coronary artery from the posterior sinus in one), left circumflex branch from right aortic sinus or from very proximal right coronary artery in three, high takeoff of right coronary artery in three, stenosis of the coronary ostia attributable to valvelike ridge in four. In 16 (59%) patients (12 males and 4 females, age ranging from 2 months to 53 years; median, 14), the final outcome was sudden death; it occurred in all cases of left coronary artery origin from right aortic sinus, in 43% of right coronary artery origin from left aortic sinus, and in 40% of the left coronary artery from the pulmonary trunk. Sudden death was precipitated by effort in eight (50%) and was the first manifestation of the disease in eight (50%); previous symptoms consisted of recurrent syncope in four, palpitations in three, and chest pain in one. Five patients who died suddenly during effort were athletes. In conclusion, (1) more than half of our postmortem cases with anomalous origin of coronary arteries died suddenly, (2) all but two patients with sudden death had anomalous coronary artery origin from the aorta itself, (3) the fatal event was frequently precipitated by effort, (4) palpitations, syncope, and ventricular arrhythmias were the only prodromic symptoms and signs. Recognition during life of these coronary anomalies, by the use of noninvasive procedures, is mandatory to prevent the risk of sudden death and to plan surgical correction if clinically indicated.

Adolescent↗

Frequency in the anomalous origin of the right coronary artery with angiography in a Turkish population.

OBJECTIVE: The estimate frequency of anatomic variations in origin of the right coronary artery in a Turkish population. MATERIAL AND METHOD: The angiographic data of 5253 consecutive adults patients undergoing coronary angiography were analysed retrospectively for the diagnosis of anomalous origin of the right coronary artery. RESULTS: Among 5253 adults patients, five (0.09%) patients had anomalous origin of the right coronary. They had an isolated anomalous origin of the right coronary artery. The right coronary arose from the left coronary sinus of Valsalva (there was separate orificium for the right coronary artery and the left coronary artery) in two (0.03%) patients, from above the left coronary sinus of Valsalva in three (0.05%) patients. In all patients, the anomalous origin of right coronary artery from the left sinus of Valsalva and from above the left coronary sinus of Valsalva coursed between the aorta and the pulmonary artery. CONCLUSION: The anomalous origin of the right coronary artery is a rare congenital cardiac malformation. Most patients remain asymptomatic. However, there are cases of sudden cardiac death described in the literature, indicating a potentially malign course of the disease. The angiographic recognition of this vessel may be useful for physicians dealing with diagnosis and treatment of the anomaly of the right coronary artery.

Coronary Angiography↗

[Use of statistical analysis in original articles in "Actas Urológicas Españolas." Accessibility for the reader].

OBJECTIVES: To describe the use of statistical methods employed in original articles published in Actas Urológicas Españolas as the first step to quantify the accessability for the readers. METHODS: Observational, retrospective, descriptive and transversal study to analize all the original articles published in Actas Urológicas Españolas during the year 2000. Once the anectotic cases were excluded, 55 original studies were selected. In each article it was minuciously reviewed the methods and results sections, tables and figures included, to identify the statistical analysis used and to classify them into 18 categories with three accessability levels as Emerson and Colditz and Mora y cols, previously reported: descriptive statistics, bivariables analysis and complex analysis. A randomized sample of the originals were reviewed again by the same investigator three months later to evaluate the criteria liability. The accessability was defined as a) article dependent (rate of originals that readers with different statistical knowledge are able to understand) and b) analysis dependent (rate of statistical methods respect to the total performed overall the articles that readers are able to understand). RESULTS: Our major findings are that the more frequently used technics are descriptive analysis (39.3%), bivariable tables (12.1%), survival analysis (10%), t Student and z tests (6%), and nonparametric tests (8.6%). The accessability for a reader which statistical konowledge includes bivariable methods is 63.6% (IC 95% 49%-76%) and 79% (IC 95% 71%-85), article and analysis dependent respectively, rates that are similar to the reported for biomedical journals in our country. CONCLUSIONS: A great percentage of original articles in Actas Urológicas Españolas includes complex analysis. It could be good that readers were able to increase our statistical and methodological knowledge to perform a critical approach to our publication.

Bibliometrics↗

Diversity of sequence haplotypes associated with beta-thalassaemia mutations in Algeria: implications for their origin.

We report the allelic sequence polymorphism associated with seven beta-thalassaemia mutations. Thirty-two DNAs originating from Algeria and 12 DNAs from Sardinia and Sicily were investigated. Their analysis revealed an association with a unique haplotype for three beta-thalassaemia mutations (-29, IVS-I-2 and IVS-I-1). It seems clear that these mutations have a unicentric origin. The presence of the -29 mutation could be explained by migration and founding effect. However, the local origin of IVS-I-2 seems clear. The four other mutations, FS6, IVS-I-6, IVS-I-110 and stop39 were found to be associated with at least two different sequence haplotypes. The likelihood of so many recurrent nucleotide dimorphisms in different lineages as a consequence of random mutation is very low; it is supported neither by the analysis of equivalent regions in other primates, nor by the presence of highly mutable sites such as CpG dinucleotides. The fact that these mutations are found exclusively in the Mediterranean area is not in favour of a recurrent origin of the mutation. The diversity is far more important for the preponderant thalassaemia mutations of the Mediterranean area and is higher in the 5' part of the beta-globin gene. Hence, the IVS-I-110, the preponderant beta-thalassaemia in the Eastern Mediterranean, probably emerged in the extension of the fertile crescent. For the stop39, all the data support the hypothesis of a West-Mediterranean origin. The diversity of haplotypes would then be generated by recombination events (crossing-over or gene conversions) between the original beta-thalassaemia chromosome and the other chomosomal structures present in the normal population.

Algeria↗

Origin of new genes and source for N-terminal domain of the chimerical gene, jingwei, in Drosophila.

This paper deals with a general question posed by the origin of new processed chimerical genes: when a new retrosequence inserts into a new genome position, how does it become activated and acquire novel protein function by recruiting new functional domains and regulatory elements? Jingwei (jgw), a newly evolved functional gene with a chimerical structure in Drosophila, provides an opportunity to examine such questions. The source of its exon encoding C-terminal peptide has been identified as an Adh retrosequence, which extends the concept of exon shuffling from recombination to retroposition as a general molecular mechanism for the origin of a new gene. However, the origin of 5' exons remains unclear. We examined two hypotheses concerning the origin of these non-Adh-derived jgw exons: (i) these exons might originate from a unique genomic sequence that fortuitously evolved a standard intron-exon structure and regulatory sequence for jgw; (ii) these exons might be a duplicate of an unrelated previously existing gene. Genomic Southern analysis, in conjunction with construction and screening of a genomic bookshelf (sub-library), was conducted in a group of Drosophila species. The results demonstrated that there are duplicate genes containing the same structure as the recruited portion of jgw. We name this duplicate gene in Drosophila teissieri and Drosophila yakuba and its orthologous gene in Drosophila melanogaster as yellow-emperor (ymp). Thus, the 5' exons/introns originated from a previously existing gene that provided new modules with specific sub-function to create jgw.

Amino Acid Sequence↗

Repetitive monomorphic ventricular tachycardia originating from the aortic sinus cusp: electrocardiographic characterization for guiding catheter ablation.

OBJECTIVES: We sought to investigate the electrocardiographic (ECG) characteristics for guiding catheter ablation in patients with repetitive monomorphic ventricular tachycardia (RMVT) originating from the aortic sinus cusp (ASC). BACKGROUND: Repetitive monomorphic ventricular tachycardia can originate from the right ventricular outflow tract (RVOT) and ASC in patients with a left bundle branch block (LBBB) morphology and an inferior axis. METHODS: Activation mapping and ECG analysis was performed in 15 patients with RMVT or ventricular premature contractions. The left main coronary artery (LMCA) was cannulated as a marker and for protection during radiofrequency delivery if RMVT originated from the left coronary ASC. RESULTS: During arrhythmia, the earliest ventricular activation was recorded from the superior septal RVOT in eight patients (group 1) and from the ASC in the remaining seven patients (group 2). The indexes of R-wave duration and R/S-wave amplitude were significantly lower in group 1 than in group 2 (31.8+/-13.5% vs. 58.3+/-12.1% and 14.9+/-9.9% vs. 56.7+/-29.5%, respectively; p < 0.01), despite similar QRS morphology. In five patients from group 2, RMVT originated from the left ASC, with a mean distance of 12.2+/-3.2 mm (range 7.3 to 16.1) below the ostium of the LMCA. In the remaining two patients, the RMVT origin was in the right ASC. All arrhythmias were successfully abolished. None of the patients had recurrence or complications during 9+/-3 months of follow-up. CONCLUSIONS: On the surface ECG, RMVT from the ASC has a QRS morphology similar to that of RVOT arrhythmias. The indexes of R-wave duration and R/S-wave amplitude can be used to differentiate between the two origins. Radiofrequency ablation can be safely performed within the left ASC with a catheter cannulating the LMCA.

Adolescent↗

ATP-dependent recognition of eukaryotic origins of DNA replication by a multiprotein complex.

A multiprotein complex that specifically recognizes cellular origins of DNA replication has been identified and purified from the yeast Saccharomyces cerevisiae. We observe a strong correlation between origin function and origin recognition by this activity. Interestingly, specific DNA binding by the origin recognition complex is dependent upon the addition of ATP. We propose that the origin recognition complex acts as the initiator protein for S. cerevisiae origins of DNA replication.

Adenosine Triphosphate↗

ATR and ATM regulate the timing of DNA replication origin firing.

Timing of DNA replication initiation is dependent on S-phase-promoting kinase (SPK) activity at discrete origins and the simultaneous function of many replicons. DNA damage prevents origin firing through the ATM- and ATR-dependent inhibition of Cdk2 and Cdc7 SPKs. Here, we establish that modulation of ATM- and ATR-signalling pathways controls origin firing in the absence of DNA damage. Inhibition of ATM and ATR with caffeine or specific neutralizing antibodies, or upregulation of Cdk2 or Cdc7, promoted rapid and synchronous origin firing; conversely, inhibition of Cdc25A slowed DNA replication. Cdk2 was in equilibrium between active and inactive states, and the concentration of replication protein A (RPA)-bound single-stranded DNA (ssDNA) correlated with Chk1 activation and inhibition of origin firing. Furthermore, ATM was transiently activated during ongoing replication. We propose that ATR and ATM regulate SPK activity through a feedback mechanism originating at active replicons. Our observations establish that ATM- and ATR-signalling pathways operate during an unperturbed cell cycle to regulate initiation and progression of DNA synthesis, and are therefore poised to halt replication in the presence of DNA damage.

Animals↗

The effect of geographic origin on the frequency of HLA antigens and their association with ageing.

The association between HLA antigens and ageing is not clear. Ageing in women was associated with B40 and DR5 in a recent study, but other studies yielded conflicting results. In none of the studies, however, did the young and elderly samples originate from the same homogeneous population. Homogeneity is dependent on geographic origin. The aim of this study was to investigate whether differences in geographic origin between age groups could explain the age-associated differences in the frequencies of B40 and DR5. The authors used the new design of a 'birth-place-restricted comparison' in which the origin of all subjects was ascertained. The total study population comprised 1010 young women aged 25-40 years and 660 elderly women aged 85 years and older. The 'birth-place-restricted comparison' included 66 young and 285 elderly women from one geographic area (Leiden, the Netherlands). Men were not included because ageing in men was not associated with HLA antigens in a recent study. In the total population, the frequency of B40 in young women of different origin varied between 16 and 28%, and the frequency of DR5 between 11 and 23%. Similar differences were observed in the elderly women. In the 'birth-place-restricted comparison', the frequency of B40 was 15% in the young women and 11% in the elderly women (difference 4%, 95% confidence interval, -5 to 13%). The frequency of DR5 was 20% in the young women, and 28% in the elderly women (difference 8%, 95% confidence interval, -4 to 19%). Thus, marked differences in HLA antigen frequency were found between populations of various geographic origins. Definition and ascertainment of the target population are therefore necessary in genetic studies of ageing. In such a 'birth-place-restricted comparison', the authors confirmed that ageing in women was negatively associated with HLA-B40 and positively associated with HLA-DR5.

Adult↗

Ber-EP4 immunoreactivity depends on the germ layer origin and maturity of the squamous epithelium.

AIM: To map the expression of Ber-EP4 in well-differentiated squamous epithelia, metaplastic squamous epithelia and dysplastic squamous epithelia of different origins. METHODS AND RESULTS: Squamous epithelium of different origin was stained using a standard immunohistochemistry method applied to paraffin sections. We found that normal squamous epithelium of the oral cavity, oesophagus, uterine cervix, vagina, anal canal, and branchial cysts are Ber-Ep4-negative, as are the mature squamous metaplasia of bronchial mucosa, urinary bladder mucosa and uterine cervical mucosa. In contrast, immature squamous metaplasia of bronchial mucosa, or uterine cervical mucosa, and squamous dysplasia of oral mucosa of endodermal origin, or uterine cervical mucosa in most cases expressed Ber-EP4. CONCLUSION: Squamous epithelia of ectodermal origin never express Ber-EP4, whether normal, hyperplastic, dysplastic or neoplastic. In contrast, squamous epithelium of endodermal origin sometimes contains the target glycoproteins of Ber-EP4 when immature, metaplastic, dysplastic or neoplastic. The results indicate that the differences in expression of Ber-EP4 in squamous epithelium depend primarily on germ layer origin, and on the maturity of the epithelium.

Antigens, Surface↗

Magnetocardiographic and magnetic resonance imaging for noninvasive localization of ventricular arrhythmia origin in a model of nonischemic cardiomyopathy.

Ventricular arrhythmia may in myocardial failure arise as a consequence of remodeling related to hypertrophy and dilatation. In surgically repaired tetralogy of Fallot (TOF), which carries a substantial risk for ventricular arrhythmias and sudden death, the situation is even more complex and several potential arrhythmia mechanisms exist. The authors wanted to test a completely noninvasive localization technique, magnetocardiography (MCG) and magnetic resonance imaging (MRI), to define the origin of ventricular ectopic beats (VEBs) in this model of nonischemic cardiomyopathy. The study included 84 patients with surgically repaired TOF, all 11 subjects with VEBs Lown grade > or = 2 on a 24-hour Holter were included. From 37-channel MCG registrations, the underlying current dipole was computed for the VEBs, and for anatomic correlation MRIs were produced. Eight patients had VEBs of altogether 11 morphologies during the MCG recording. The RVOT was the origin of 6 VEBs, while 4 originated from the RV free wall, and 1 VEB could not be localized. Applying this completely noninvasive technique, it was possible to define different origins of RV ectopies in a complex heart model. Thus, VEBs originated from the RVOT, suggesting a relation to surgical scars and from the nonoperated parts of the RV, supporting that ventricular remodeling might be of equal importance for arrhythmogenesis in this model of cardiomyopathy. This technique can assist in answering the important question of whether there is any difference in prognostic information depending on the origin and related mechanism of VEBs in this and other high risk conditions.

Adult↗

Origin and course of the coronary arteries in normal mice and in iv/iv mice.

This paper reports on the origin and distribution of the coronary arteries in normal mice and in mice of the iv/iv strain, which show situs inversus and heterotaxia. The coronary arteries were studied by direct observation of the aortic sinuses with the scanning electron microscope, and by examination of vascular corrosion casts. In the normal mouse, the left and right coronaries (LC, RC) arise from the respective Valsalva sinus and course along the ventricular borders to reach the heart apex. Along this course the coronary arteries give off small branches at perpendicular or acute angles to supply the ventricles. The ventricular septum is supplied by the septal artery, which arises as a main branch from the right coronary. Conus arteries arise from the main coronary trunks, from the septal artery and/or directly from the Valsalva sinus. The vascular casts demonstrate the presence of intercoronary anastomoses. The origin of the coronary arteries was found to be abnormal in 84% of the iv/iv mice. These anomalies included double origin, high take-off, slit-like openings and the presence of a single coronary orifice. These anomalies occurred singly or in any combination, and were independent of heart situs. The septal artery originated from RC in most cases of situs solitus but originated predominantly from LC in situs inversus hearts. Except for this anomalous origin no statistical correlation was found between the coronary anomalies and heart situs or a particular mode of heterotaxia. The coronary anomalies observed in the iv/iv mice are similar to those found in human hearts. Most coronary anomalies appear to be due to defective connections between the aortic root and the developing coronaries. iv/iv mice may therefore constitute a good model to study the development of similar anomalies in the human heart.

Animals↗

Maternal ethnic origin and fetal nasal bones at 11-14 weeks of gestation.

OBJECTIVES: Failure to visualise the fetal nasal bones at 11-14 weeks of gestation is associated with a significant increase in the risk for trisomy 21. However, it is not known whether the ethnic origin of the mother has any effect on the fetal profile and the prevalence of this marker. DESIGN: Prospective study. SETTING: London Teaching Hospital. POPULATION: Four thousand and four hundred and ninety-two consecutive fetuses undergoing routine first trimester ultrasound scanning at 11-14 weeks of gestation in a multiethnic population. METHODS: Examination of the nasal bones was attempted in the fetuses. MAIN OUTCOME MEASURE: Rate of visualisation of the fetal nasal bones. RESULTS: Five hundred fetuses were excluded from the analysis because of chromosomal abnormalities or a technically unsatisfactory examination. In the remaining 3992 fetuses, the maternal ethnic origin was African in 13.0%, Asian in 15.3% and Caucasian in 66.0%. Compared with Caucasians, the failure to visualise the fetal nasal bones was significantly higher in women of African (P= 0.0001) but not Asian origin (P= 0.24). A multivariable logistic regression model showed that having a mother of African origin is still significantly associated with an increased likelihood of absent fetal nasal bones compared with Caucasians (odds ratio 2.33), even after correcting for maternal age, parity and crown-rump length. CONCLUSION: There is a significant difference in the rate of visualisation of the fetal nasal bones in the first trimester in mothers of different ethnic origin. This suggest that corrections for maternal ethnicity will be required to ensure equity of fetal nasal bone screening in multiracial populations. Whether corrections are required for the father's ethnic origin remains to be determined.

Adult↗