Glycosaminoglycans and proteoglycans in the skin of aneuploid fetuses with increased nuchal translucency

Turner's syndrome associated with discoid lateral meniscus and Blount's disease: a case report

Background

Turner’s syndrome, discoid meniscus, and Blount’s disease have all been studied in isolation, but, to the best of our knowledge, there have been no studies reporting a patient with all three. Thus, the first case of Turner’s syndrome with discoid meniscus and Blount’s disease is presented.

Case presentation

A 5-year-old Japanese girl with a history of Turner’s syndrome and Blount’s disease complained of pain in her left knee. Magnetic resonance imaging showed a discoid lateral meniscus tear, and arthroscopic partial meniscectomy was performed, providing a good outcome.

Conclusions

In this report, some possible explanations regarding the concomitant presence of these three diseases are discussed. A possible explanation in this case is that the patient with Turner’s syndrome had a discoid lateral meniscus that might have been induced by some genetic factors associated with Turner’s syndrome, and then the discoid lateral meniscus might have been the mechanical stress that caused Blount’s disease.

Evidence of biglycan structure-function in bone homeostasis and aging

Purpose: Biglycan is a proteoglycan of the small leucine-rich repeat family. It is present in all connective tissues and plays key structural and signaling roles. This review aimed to compile available evidence in the characteristics and distribution of biglycan and its glycosylated and non-glycosylated forms in connective tissues with a specific focus on the contribution to homeostasis of bone and changes of biglycan structure with aging.Methods: The Pubmed database was searched and included the terms "biglycan", "proteoglycans", "glycosaminoglycans", "bone", "osteoblast", "osteocyte", "osteoclast", "aging", "inflammation", "cartilage". Abstracts were appraised and a series of original articles and reviews studied to generate this narrative review.Results: Based on the search, biglycan significantly affects bone development and homeostasis and can be significantly changed by the aging process in several connective tissues, which in turn affects the behavior of tissue and cell responses in aged networks. Further, as the understanding of the various forms of biglycan in vivo is expanded and the function of its components in vitro is dissected, this proteoglycan can potentially serve as a therapeutic or biomarker molecule to detect tissue destruction.Conclusions: Biglycan is a key player in skeletal bone homeostasis, and overall, there is more evidence on the role of biglycan in development and less in the adult physiological or diseased young and aged systems. Further understanding of its conformation, degradation peptides and post-translational modifications will be required to understand the role of biglycan in bone maintenance and to support the development of treatments for age-related bone dysfunctions.

What can be inferred if the fetal increased nuchal translucency thickness changes?

Objectives: To study the perinatal outcomes in the women who's the different changes of an increased fetal nuchal translucency thickness.Methods: Since 2013-2016, the pregnant women whose initial measurement of fetal nuchal translucency (NT) ≥ 3.5 mm would be invited to scan the NT again after a week. Between the two measurements over 1 mm, defined as "change". According to different results between two measurements, they were divided into three groups: unchanged group, thinned group and thicken group. To follow-up and compare the perinatal outcomes among the three groups.Results: One hundred seventy-five cases met our criteria and were retrieved in the study. There are 90 cases of the unchanged group, 60 cases of the thinned group and 25 cases of thicken group. Among three groups, the chromosomal abnormalities rate is 11.11, 21.67, and 60.0% respectively, the structure abnormalities rate is 10.0, 8.51, and 20.0%, the normal delivery rate is 76.67, 70.0, and 28.0%. There all have the significantly differences in statistics except the structure abnormalities rate.Conclusion: The chromosomal abnormalities rate and adverse perinatal outcome rate were worse if NT continues to thicken. However, the perinatal outcome of the NT thinned group is no better than the NT unchanged case.

Aortic elasticity deterioration proves intrinsic abnormality of the ascending aorta in pediatric Turner syndrome unrelated to the aortic valve morphology

Turner syndrome (TS) is a common genetic disorder in females with high incidence of ascending aortic dilatation and even dissection occurring as early as in the second decade. Known risk factors (RF) are bicuspid aortic valves (BAV), coarctation of the aorta (CoA), and arterial hypertension. Since 10% of dissections occur in patients without RF, an intrinsic aortic wall abnormality has been postulated. This study aimed to investigate the elasticity of the ascending aorta as a surrogate marker of aortic wall texture. Forty-six pediatric patients with genetically proven TS were prospectively examined for the morphology of their aortic valve, and size and elasticity indices of the adjacent aorta. Cohorts of 46 female subjects with tricuspid aortic valves (TAV) and ten non-syndromic females with BAV were investigated as separate control groups. Comparison of healthy controls with TS patients revealed significantly deteriorated elasticity indices in those with TS. Furthermore, normalized aortic dimensions were greater in TS patients, but dilatations of the ascending aorta with z-score levels above two were restricted to those with BAV (14/46). Deteriorated elasticity indices were measured in TS patients, independent of aortic dilatation, BAV, and CoA, and were comparable to those of patients with isolated, non-syndromic BAVs. By measuring elasticity levels as a surrogate for aortic wall texture, we were able to gather evidence that TS presents with an intrinsic abnormality of the ascending aorta even in patients without concomitant BAV, CoA or dilatations as early as in childhood.

Maternal serum placental growth factor at 11-13 weeks' gestation and fetal cardiac defects

OBJECTIVE

To investigate the relationship between fetal heart defects and maternal serum placental growth factor (PlGF), a marker of placental angiogenesis.

METHODS

Maternal serum PlGF, pregnancy-associated plasma protein-A (PAPP-A) and uterine artery pulsatility index (UtA-PI) at 11-13 weeks' gestation were compared in 68 cases of isolated fetal major heart defects and 340 normal controls. Variables were converted into multiples of the median (MoM) after adjustment for gestational age, maternal age, racial origin, weight, parity and method of conception, and then compared between groups. The cardiac defects included 11 cases of obstruction of the left ventricular outflow tract (LVOT), 25 conotruncal abnormalities and 32 valve defects.

RESULTS

The median PlGF-MoM in the heart defect group was lower than in controls (0.80 (interquartile range (IQR), 0.57-1.08) vs 1.00 (IQR, 0.79-1.32); P < 0.0001). Low PlGF levels were observed in the presence of conotruncal and valve defects but not in the presence of LVOT defects. There was no significant difference between the group with fetal heart defects and controls in PAPP-A-MoM (0.95 (IQR, 0.68-1.28) vs 1.01 (IQR, 0.70-1.39); P = 0.292) or UtA-PI-MoM (1.01 (IQR, 0.84-1.28) vs 0.99 (IQR, 0.80-1.20); P = 0.396).

CONCLUSION

In pregnancies with isolated fetal heart defects there is evidence of impaired placental angiogenesis in the absence of impaired placental perfusion and function.

Cardiovascular phenotype in Turner syndrome--integrating cardiology, genetics, and endocrinology

Cardiovascular disease is emerging as a cardinal trait of Turner syndrome, being responsible for half of the 3-fold excess mortality. Turner syndrome has been proposed as an independent risk marker for cardiovascular disease that manifests as congenital heart disease, aortic dilation and dissection, valvular heart disease, hypertension, thromboembolism, myocardial infarction, and stroke. Risk stratification is unfortunately not straightforward because risk markers derived from the general population inadequately identify the subset of females with Turner syndrome who will suffer events. A high prevalence of endocrine disorders adds to the complexity, exacerbating cardiovascular prognosis. Mounting knowledge about the prevalence and interplay of cardiovascular and endocrine disease in Turner syndrome is paralleled by improved understanding of the genetics of the X-chromosome in both normal health and disease. At present in Turner syndrome, this is most advanced for the SHOX gene, which partly explains the growth deficit. This review provides an up-to-date condensation of current state-of-the-art knowledge in Turner syndrome, the main focus being cardiovascular morbidity and mortality. The aim is to provide insight into pathogenesis of Turner syndrome with perspectives to advances in the understanding of genetics of the X-chromosome. The review also incorporates important endocrine features, in order to comprehensively explain the cardiovascular phenotype and to highlight how raised attention to endocrinology and genetics is important in the identification and modification of cardiovascular risk.

Abnormal ductus venosus flow in first-trimester fetuses with increased nuchal translucency: relationship with the type of cardiac defect?

OBJECTIVE

The purpose of this study was to evaluate ductus venosus flow velocities and a possible relationship with the type of cardiac defect in fetuses with increased nuchal translucency (NT).

METHODS

Seventy-two fetuses with normal NT and 137 fetuses with increased NT (>95th percentile) were evaluated. The ductus venosus pulsatility index for veins (PIV), late diastolic velocity (velocity during atrial contraction [a-V]), and intracardiac velocities were evaluated. In cases of pregnancy termination, a postmortem examination was performed. Cardiac defects were grouped into septal defects, left and right inflow obstruction, left and right outflow obstruction, and other defects. Data were evaluated by multilevel analysis.

RESULTS

A cardiac defect was found in 45 fetuses with increased NT. Fetuses with increased NT showed a higher ductus venosus PIV and a lower a-V compared to fetuses with normal NT (P < .05). Within the group of fetuses with increased NT, a higher PIV and a lower a-V were found in cases with a cardiac defect compared to cases with a normal heart (P < .001). No differences in PIV and a-V were found between the types of cardiac defects. Intracardiac velocities showed no differences between fetuses with normal and increased NT, irrespective of the presence of a cardiac defect.

CONCLUSIONS

Ductus venosus flow velocities in fetuses with increased NT are not related to a certain type of cardiac defect. This indicates that the altered ductus venosus flow velocities found in fetuses with increased NT cannot be explained by cardiac failure due to a specific altered cardiac anatomy.

First-trimester ultrasound: current uses and applications

This article is aimed to aid the sonographer and medical care provider in better interpretation and clinical application of first-trimester ultrasound findings in early pregnancy. We review current uses, applications, and interpretations of first-trimester ultrasound. A discussion of basic embryology and normal as well as abnormal first-trimester sonographic findings are discussed. We also cover the utility of the first-trimester ultrasound in screening for fetal aneuploidy. Attention is also given to the role of the first-trimester ultrasound in the prediction of adverse perinatal and maternal outcomes.

Nuchal Translucency and First Trimester Risk Assessment

First-trimester risk assessment for fetal aneuploidy using nuchal translucency (NT) measurement is rapidly gaining popularity in the United States. In combination with maternal serum markers in the first trimester, the screening performance is exceptionally good, with detection rates of more than 80% at a screen positive rate of 5%. Recently, the method has been validated for screening for Down syndrome and other aneuploidies in multicenter trials in the United States and elsewhere. Compliance with established criteria for measurement of the NT is essential to achieve uniform reliability and high screening test sensitivity. There is an international consensus about the importance of specific training in the NT examination, conformity to standards of NT measurement, and regular audit for quality assurance. In the United States, the Nuchal Translucency Quality Review program has been developed to administer credentialing and quality review for registered practitioners. The Nuchal Translucency Quality Review credentials signify the proficiency of the sonographer or sonologist in NT measurement and participation in a regular quality assurance audit. We encourage accreditation of clinical sites offering first-trimester risk assessment to ensure the highest quality care.

Quantitative evaluation of collagen type VI and SOD gene expression in the nuchal skin of human fetuses with trisomy 21

OBJECTIVE

To investigate the involvement of the genes encoding for COL6A1, COLA2 and super-oxide dismutase (SOD) in the mechanism for the retention of subcutaneous fluid in fetuses with trisomy 21.

METHODS

During a 7-month period (November 2004-May 2005), human fetal skin from the nuchal region was obtained from euploid fetuses and from fetuses with trisomy 21 following abortions and terminations of pregnancy. Cell cultures were performed from nuchal skin. Quantification of COL6A1, COL6A2, COL6A3 and SOD mRNAs were performed using real-time quantitative RT-PCR.

RESULTS

Twelve fetuses were studied between 13-15 and 19-20 weeks of gestation including 7 cases of trisomy 21. A significant overexpression of genes of interest was demonstrated in trisomy 21 fetuses when compared with euploid fetuses, in the first and in the second trimester of pregnancy (p < 0.0001).

CONCLUSION

This study demonstrates a homogeneous overexpression of the genes encoding for alpha1 and alpha2 chains of Collagen type VI, and SOD in nuchal skin of human trisomy 21 fetuses. Persistence of this overexpression in the second trimester of pregnancy, despite the absence of an enlarged nuchal translucency (NT), may characterize some compensatory mechanisms.

Clinical and epidemiological description of aortic dissection in Turner's syndrome

BACKGROUND

Women with Turner's syndrome have an increased risk of congenital cardiac malformations, ischaemic heart disease, hypertension and stroke. Aortic dissection seems to occur with increased frequency.

AIM

To describe in more detail aortic dissection as encountered in Turner's syndrome, giving attention to clinical, histological and epidemiological aspects.

MATERIALS AND METHODS

Based on a retrospective study, we describe the clinical, karyotypic, and epidemiological aspects of aortic dissection as encountered in cases of Turner's syndrome seen in Denmark and Sweden.

RESULTS

The median age at onset of aortic dissection in 18 women was 35 years, ranging from 18 to 61 years. Fourteen of 18 women had a 45,X karyotype, while 2 patients had 45,X/45,XY, and 2 had the 45,X/46,X+r(X) complement, respectively. Echocardiography was performed in 10 of 18 patients before their acute illness, and showed signs of congenital cardiac disease, with either bifoliate aortic valves, dilation of the aortic root, or previous aortic coarctation evident in most patients. In 5 patients evidence of a bifoliate aortic valve was conclusive. Hypertension was present in 5 of 18 patients, while 10 of the patients died from aortic dissection, of so-called type A in 6, type B in 3, while in the final case the origin of dissection could not be determined. Biochemical analysis showed altered ratio between type I and type III collagen. Histology showed cystic medial necrosis in 3 of 7 cases. We estimated an incidence of dissection of 36 per 100,000 Turner's syndrome years, compared with an incidence of 6 per 100,000 in the general population, and a cumulated rate of incidence of 14, 73, 78, and 50 per 100,000 among 0-19, 20-29, 30-39, and 40+ year olds, respectively.

CONCLUSION

Aortic dissection is extremely common in the setting of Turner's syndrome, and occurs early in life. Patients with Turner's syndrome should be offered a protocol for clinical follow-up similar to that provided for patients with Marfan syndrome, and each clinic should embrace a programme for follow-up.

Temporal Relationship Between Increased Nuchal Translucency and Enlarged Jugular Lymphatic Sac

OBJECTIVE

To study the relationship between the volume of the jugular lymphatic sacs and nuchal translucency thickness in fetuses with increased nuchal translucency with advancing gestation.

METHODS

Seventy-four fetuses with a nuchal translucency greater than the 95th percentile were examined weekly between 11 and 17 weeks of gestational age. The fetal neck region was studied by ultrasonography, followed by measurement of nuchal translucency and jugular lymphatic sacs. The measurements were analyzed using multilevel analysis. In case of termination of pregnancy postmortem examination was performed.

RESULTS

In 40 euploid fetuses and 34 aneuploid fetuses, 159 measurements of jugular lymphatic sac volume and nuchal translucency thickness were analyzed. The volume of the jugular lymphatic sacs and gestational age showed a quadratic relation, which differed between euploid and aneuploid fetuses (P < .01). The maximum volumes were larger and present longer in fetuses with aneuploidy than in euploid fetuses (P < .01). In case of a cardiac anomaly, jugular lymphatic sac volume was larger than in cardiac normal fetuses (nonsignificant). Furthermore, the development of jugular lymphatic sac volume and increased nuchal translucency were related, whereby an increase of the nuchal translucency preceded enlargement of the jugular lymphatic sacs (P < .001). In each fetus an increase in jugular lymphatic sac volume was followed by a decrease with advancing gestation. The gestational age at maximum jugular lymphatic sac volume differed between fetuses, indicating a fetus-specific pattern. Nuchal translucency development showed a similar pattern. Postmortem examination confirmed distension of the jugular lymphatic sacs in all cases.

CONCLUSION

Increased nuchal translucency is associated with abnormal lymphatic development, in which nuchal translucency enlargement precedes enlargement of jugular lymphatic sacs on ultrasound examination. Aneuploid fetuses have a more disturbed lymph angiogenesis.

LEVEL OF EVIDENCE

III.

Prenatal diagnosis of Turner syndrome: report on 69 cases

OBJECTIVE

This study was conducted to evaluate the diagnostic value of different sonographic signs of fetuses with Turner syndrome in the first and second trimesters of pregnancy.

METHODS

Between 1990 and 2004, Turner syndrome was found in 69 of 22,150 fetal karyotypings. Congenital anomalies detected by sonography were analyzed.

RESULTS

Of the 514 (2.3%; 514/22,150) chromosome aberrations that were diagnosed, 69 Turner syndrome cases were found (13.4%; 69/514). Twenty-four fetuses had a 45,X karyotype (34.8%), and 45 fetuses were mosaic (65.2%). Forty-seven fetuses (68.1%; 47/69) showed symptoms on sonography. A substantial proportion of fetuses with Turner syndrome showed early-onset signs that could be detected in the first trimester (29.8%;14/69). The most common findings with sonography were hygroma colli (26.1%; 18/69), fetal hydrops (11.6%; 8/69), cardiac defects (13%; 9/69), and increased nuchal translucency (13%; 9/69). Among heart defects, coarctation of the aorta was the most common (44.4% of all cardial defects). Soft markers were also detected with relatively high frequency (23.2%; 16/69).

CONCLUSIONS

The diagnosis of severe Turner syndrome is possible in early pregnancy. A search for soft markers during second-trimester sonography and extensive use of echocardiography may increase the detection rate of Turner syndrome.

Evidence of genetic underexpression in chorionic villi samples of euploid fetuses with increased nuchal translucency at 10-11 weeks' gestation

OBJECTIVE

To retrospectively investigate whether the genetic profile from chorionic villous sampling (CVS) found in euploid fetuses with increased NT differs from matched controls.

STUDY DESIGN

We employed cDNA microarray technology to characterize and compare the gene expression profile of chorionic villous tissues (which encompass the trophoblast and inner mesenchymal core) belonging to four singleton male fetuses with increased NT at 10-11 weeks' gestation. A pool of four normal chorionic villous tissues belonging to four respective fetuses, matched for gestational age and gender, was used as controls.

RESULTS

In euploid fetuses, we found several underexpressed genes, possibly involved in mechanisms associated with the abnormal NT thickness. All these genes are likely to belong to the mesenchymal core of the villus that originates from the extraembryonic mesoderm, and thus might be closely representative of the embryonic genetic profile. They include: (1) genes of embryonic development and differentiation such as Endothelin 3 (EDN3) and secreted frizzled-related protein 4 (SFRP4); (2) genes of the extracellular matrix (ECM) metabolism such as tissue inhibitor of metalloproteinase1 (TIMP1), and disintegrin-like and matrix metalloproteinase (MMP) (reprolysin type) with thrombospondin type 1 Motif or ADAMTS2, exostoses (multiple)-like 1 (EXTL1), heparan sulfate (HS) 6-O-sulfotransferase 1 or HS6ST1, fibronectin 1 (FN1) and Integrin Alpha 10 (ITGA10) involved in HS and proteoglycan bio-synthesis, ECM synthesis and cell-matrix adhesion; (3) genes involved in vessel formation and differentiation such as angiogenic factor (VG5Q), and in blood pressure control and muscle contraction, like Endothelin 3 or EDN3 and sarcolemma associated protein (SLMAP). Such lower expressions of the villous tissues might be related to an immature genetic profile of the embryo development as well as abnormal regulation of ECM bio-synthesis and/or improper vessel growth and blood pressure control. Also, the results partially support the theories proposed for NT enlargement such as altered composition of ECM and abnormal/delayed development of the circulatory system.

CONCLUSIONS

Abnormal extraembryonic genetic expression is found at 10-11 weeks' gestation in euploid fetuses with increased NT. If both extra- and intraembryonic mesoderms express the same genetic alterations, then microarray analyses on CVS could be used to screen several mesoderm-derivate anomalies.

Increased NCAM expression and vascular development in trisomy 16 mouse embryos: relationship with nuchal translucency

Increased nuchal translucency in the human fetus is associated with chromosomal abnormalities, enlarged jugular lymphatic sacs, cardiac defects and changed flow through the ductus venosus. The developmental background of this nuchal edema in relation to the associated anomalies remains elusive. We studied the morphologic correlation between neurogenesis and vasculogenesis in neck, heart, and ductus venosus region of wild type and trisomy 16 mice embryos (E10- E18), using an antibody against Neural Cell Adhesion Molecule (NCAM). Trisomy 16 mice are a model for the above described human phenotype. From E12 trisomy 16 mice showed an altered arrangement of cranial nerves IX, X and XI, which are positioned between the carotid artery, jugular vein and enlarged lymphatic sac. The vagal nerve was significantly smaller, compared with wild type embryos. NCAM was over expressed in both neuronal and cardiovascular structures in trisomy 16 mice, being particularly prominent in the 4th and 6th pharyngeal arch arteries, and the ductus venosus. In the 4th and 6th pharyngeal arch arteries, NCAM over expression was located to the part of the vessel wall that is closely related to the vagal and recurrent nerve. In case of 4th pharyngeal arch artery abnormalities NCAM expression, on the other hand, was reduced. In conclusion, the interaction between neurogenesis and vasculogenesis is disturbed in the trisomy 16 mouse model, and might be a common denominator in the spectrum of anomalies associated with increased nuchal translucency.

Hyaluronan content of Wharton's jelly in healthy and Down syndrome fetuses

The mechanisms by which the excess genetic material of chromosome 21 results in the dysmorphologic features of Down syndrome (DS) are largely unknown. It has been found that the extracellular matrix of nuchal skin of DS fetuses exhibits an higher content of hyaluronan (HA) compared to that of euploid fetuses. Since HA plays a central role in many morphogenetic processes during embryogenesis, an alteration in its metabolism could be involved in the pathogenesis of several structural defects of DS. The extracellular matrix of umbilical cord (UC) is the mammalian tissue with one of the highest content of HA. Therefore we sought to explore the quantitative HA modifications during gestation, tissue distribution and HA metabolism in euploid and DS UCs. Euploid UCs (n=28) and UCs from DS fetuses (n=13) were obtained after termination of pregnancy, spontaneous abortion, or at delivery. Quantitative and molecular size analysis were performed using HPLC and FPLC. Tissue distribution was visualized by immunohistochemistry. Gene expression for HA synthases (HAS) and hyaluronidases (HYAL) were quantified by real-time PCR techniques and HYAL activity was detected by zymography. In euploid UC only HA of a molecular weight of 1700 kDA was present while in DS UC an additional lower weight HA molecule of 1100 kDA was found. Immunohistochemistry showed a larger amount of Wharton's jelly HA in DS UCs than in euploid UC. Real-time PCR analysis showed that HAS 2 and HYAL 2 were expressed at significant levels in all specimens. A higher expression of HAS 2 and a lower expression of HYAL 2 was found in the Wharton's jelly of DS fetuses compared to that of euploid fetuses at 14 weeks of gestation. On the contrary, at term HYAL 2 expression was higher in DS specimens than in those from euploid fetuses. Zymographic studies showed a similar behavior with a lower HYAL activity at early gestation and a higher HYAL activity at term gestation in DS UCs compared to euploid specimens. Therefore we can conclude that HA is more represented in DS UCs than in euploid UCs. A complex alteration of the HA metabolism characterized by an increased synthesis of lower weight HA molecules is a peculiarity of DS UCs.

Increased nuchal translucency with normal karyotype

Increased fetal nuchal translucency (NT) thickness between 11 and 14 weeks' gestation is a common phenotypic expression of chromosomal abnormalities, including trisomy 21. However, even in the absence of aneuploidy, nuchal thickening is clinically relevant because it is associated with an increase in adverse perinatal outcome caused by a variety of fetal malformations, dysplasias, deformations, dysruptions, and genetic syndromes. Once the presence of aneuploidy is ruled out, the risk of perinatal outcome dose not statistically increase until the nuchal translucency measurement reaches 3.5 mm or more (>99th percentile). This increase in risk occurs in an exponential fashion as the NT measurement increases. However, if the fetus survives until midgestation, and if a targeted ultrasound at 20 to 22 weeks fails to reveal any abnormalities, the risk of an adverse perinatal outcome and postnatal developmental delay is not statistically increased.

Increased nuchal translucency and distended jugular lymphatic sacs on first-trimester ultrasound

OBJECTIVE

To investigate the presence and volume of jugular lymphatic sacs (JLS) in first-trimester fetuses with normal nuchal translucency thickness (NT) and in those with increased NT.

METHODS

This was a prospective study of 26 fetuses with NT > 95(th) percentile, which were compared with 137 fetuses with normal NT. Following crown-rump length (CRL) and NT measurement the neck region of the fetus was studied by transvaginal ultrasound. The JLS presented as spheroidal translusencies in the anterolateral region of the neck.

RESULTS

The prevalence of JLS differed significantly between fetuses with enlarged NT and the control group (P < 0.0001). In the group of 26 fetuses with increased NT, 22 had clearly visible JLS. Chorionic villus sampling revealed aneuploidy in 10 and euploidy in 16 fetuses. In the control group two fetuses, with NT values of 2.8 mm and 2.9 mm, had JLS; pregnancy outcome was normal in both cases. Logistic regression analysis in the total study group showed that an increase in NT was associated with a greater probability of JLS being present (for NT = 3-3.5 mm, probability = 0.67; for NT > 3.5 mm, probability = 0.93). In fetuses with JLS, an increase in CRL was associated with a significant increase in right JLS volume (r = 0.51; P-value = 0.01) and a non-significant increase in left sac volume (r = 0.40; P-value = 0.09). Increase in NT was not associated with a significant increase in JLS volume.

CONCLUSION

There is a significant association between increased NT and the presence of JLS on first-trimester ultrasound. In our opinion, the pathophysiological explanation for increased NT lies in a disturbance in lymphangiogenesis.