Single-cell reconstruction with spatial context of migrating neural crest cells and their microenvironments during vertebrate head and neck formation.

The dynamics of multipotent neural crest cell differentiation and invasion as cells travel throughout the vertebrate embryo remain unclear. Here, we preserve spatial information to derive the transcriptional states of migrating neural crest cells and the cellular landscape of the first four chick cranial to cardiac branchial arches (BA1-4) using label-free, unsorted single-cell RNA sequencing. The faithful capture of branchial arch-specific genes led to identification of novel markers of migrating neural crest cells and 266 invasion genes common to all BA1-4 streams. Perturbation analysis of a small subset of invasion genes and time-lapse imaging identified their functional role to regulate neural crest cell behaviors. Comparison of the neural crest invasion signature to other cell invasion phenomena revealed a shared set of 45 genes, a subset of which showed direct relevance to human neuroblastoma cell lines analyzed after exposure to the in vivo chick embryonic neural crest microenvironment. Our data define an important spatio-temporal reference resource to address patterning of the vertebrate head and neck, and previously unidentified cell invasion genes with the potential for broad impact.

Early stages of development of the alar fascia (human specimens at 6-12 weeks of development).

In recent years, there has been much discussion concerning the cervical fasciae. The aim of this study is to confirm and to describe the development of the alar fascia as well as its relationship with nearby structures. Histological preparations of 25 human embryos (6-8 weeks of development) and 25 human fetuses (9-12 weeks of development) were studied bilaterally using a conventional optical microscope. Our study confirms the existence of the alar fascia and permits three stages to be established during its development. The initial stage (1st), corresponding to the 6th week of development (Carnegie stages 18-19), is characterized by the beginning of the alar fascia primordium in the retroesophageal space at the level of C7-T1. In the formation stage (2nd), corresponding to the 7th and 8th weeks of development (Carnegie stages 20-23), the alar fascia primordium grows upwards and reaches the level of C2-C3. In the maturation stage (3rd), beginning in the 9th week of development, the visceral, alar and prevertebral fasciae can be identified. The alar fascia divides the retrovisceral space (retropharyngeal and retroesophageal) into two spaces: one anterior (between the alar fascia and the visceral fascia and extending from C1 to T1, named retropharyngeal or retroesophageal space according to the level) and the other posterior (between the alar fascia and the prevertebral fascia, named danger space). We suggest that this latter space be named the retroalar space. This study suggests that alar fascia development is related to mechanical factors and that the alar fascia permits the sliding of the pharynx and the oesophagus during swallowing.

Prenatal MRI of neck masses with special focus on the evaluation of foetal airway.

BACKGROUND: Prenatal magnetic resonance imaging is the best tool to visualize foetal airway. OBJECTIVE: To evaluate the performance of MRI in the assessment of foetal airway status in the presence of a neck mass. MATERIALS AND METHODS: Two paediatric radiologists with 12- and 2-year experience in foetal imaging retrospectively analysed 23 foetal MRI examinations, performed between 2001 and 2016, after a second-level ultrasound suspicious for presence of a neck mass. Postnatal imaging, postoperative report, histology, autopsy, and clinical outcomes were the reference standard to calculate sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of prenatal MRI in detecting airway patency. We used the Cohen к statistics to estimate the interobserver agreement. We also assessed MRI performance in the diagnosis of the mass nature. RESULTS: We obtained data about postnatal airway status in 19 of 23 patients; prenatal MRI demonstrated a sensitivity of 9/9 [100%, 95% confidence interval (CI) 66-100%], specificity 8/10 (80%, 44-98%), accuracy 17/19 (89%, 67-99%), PPV 9/11 (82%, 48-98%), and NPV 8/8 (100%, 63-100%); the interobserver agreement was perfect. Prenatal MRI correctly identified 21 of 23 masses (к = 0.858); the interobserver agreement was almost perfect (к = 0.851). CONCLUSION: Prenatal MRI demonstrated high accuracy in assessing foetal airway status and diagnosing mass nature, allowing proper delivery planning.

Clonal analysis reveals a common origin between nonsomite-derived neck muscles and heart myocardium.

Neck muscles constitute a transition zone between somite-derived skeletal muscles of the trunk and limbs, and muscles of the head, which derive from cranial mesoderm. The trapezius and sternocleidomastoid neck muscles are formed from progenitor cells that have expressed markers of cranial pharyngeal mesoderm, whereas other muscles in the neck arise from Pax3-expressing cells in the somites. Mef2c-AHF-Cre genetic tracing experiments and Tbx1 mutant analysis show that nonsomitic neck muscles share a gene regulatory network with cardiac progenitor cells in pharyngeal mesoderm of the second heart field (SHF) and branchial arch-derived head muscles. Retrospective clonal analysis shows that this group of neck muscles includes laryngeal muscles and a component of the splenius muscle, of mixed somitic and nonsomitic origin. We demonstrate that the trapezius muscle group is clonally related to myocardium at the venous pole of the heart, which derives from the posterior SHF. The left clonal sublineage includes myocardium of the pulmonary trunk at the arterial pole of the heart. Although muscles derived from the first and second branchial arches also share a clonal relationship with different SHF-derived parts of the heart, neck muscles are clonally distinct from these muscles and define a third clonal population of common skeletal and cardiac muscle progenitor cells within cardiopharyngeal mesoderm. By linking neck muscle and heart development, our findings highlight the importance of cardiopharyngeal mesoderm in the evolution of the vertebrate heart and neck and in the pathophysiology of human congenital disease.

What are the prevalence, characteristics and significance of fetal lateral neck cysts detected in an early anatomical scan?

PURPOSE: This study evaluated the association of fetal lateral neck cysts (FLNC) with adverse pregnancy outcomes, in relation to specific sonographic characteristics and co-existing findings. METHODS: Pregnancies in which FLNC were detected by a single examiner in early anatomical scans (14-16 weeks) were included. Data regarding the pregnancy and its outcome were retrieved from telephone-based questionnaires, patient charts and from the examiner's reports. RESULTS: 654 cases of FLNC were detected among 9446 early anatomical scans (6.9%). Complete data regarding 219 pregnancies were available. FLNC were significantly more prevalent in males (65.2%). The prevalence of heart malformations was 3.2% [all were non-isolated cases or with abnormal nuchal translucency (NT) and/or nuchal fold (NF)]. Amniocentesis performed in 165 pregnancies was abnormal in 1.2%. Among 206 children born from this cohort, adverse medical outcomes were reported in 5.3%. The likelihood of adverse pregnancy outcomes was significantly higher in non-isolated cases and in cases with abnormal NT or NF. Sonographic characteristics such as cyst size and bilateral findings were not linked to adverse pregnancy outcomes. CONCLUSION: Isolated FLNC are benign findings which do not require additional work up. FLNC with additional sonographic abnormalities are associated with a significantly increased risk for adverse pregnancy outcomes.

Temporal and spatial requirements for Hoxa3 in mouse embryonic development.

Hoxa3(null) mice have severe defects in the development of pharyngeal organs including athymia, aparathyroidism, thyroid hypoplasia, and ultimobranchial body persistence, in addition to defects of the throat cartilages and cranial nerves. Some of the structures altered in the Hoxa3(null) mutant embryos are anterior to the described Hoxa3 gene expression boundary: the thyroid, soft palate, and lesser hyoid horn. All of these structures develop over time and through the interactions of multiple cell types. To investigate the specific cellular targets for HOXA3 function in these structures across developmental time, we performed a comprehensive analysis of the temporal and tissue-specific requirements for Hoxa3, including a lineage analysis using Hoxa3(Cre). The combination of these approaches showed that HOXA3 functions in both a cell autonomous and non-cell autonomous manner during development of the 3rd and 4th arch derivatives, and functions in a neural crest cell (NCC)-specific, non-cell autonomous manner for structures that were Hoxa3-negative by lineage tracing. Our data indicate that HOXA3 is required for tissue organization and organ differentiation in endodermal cells (in the tracheal epithelium, thymus, and parathyroid), and contributes to organ migration and morphogenesis in NCCs. These data provide a detailed picture of where and when HOXA3 acts to promote the development of the diverse structures that are altered in the Hoxa3(null) mutant. Data presented here, combined with our previous studies, indicate that the regionally restricted defects in Hoxa3 mutants do not reflect a role in positional identity (establishment of cell or tissue fate), but instead indicate a wider variety of functions including controlling distinct genetic programs for differentiation and morphogenesis in different cell types during development.

Sonographic correlation of foetal neck circumference and area with gestational age among pregnant women in Port Harcourt, Nigeria.

The purpose of this study was to create a reference range nomogram of foetal neck circumference (FNC) and foetal neck area (FNA) in a Nigerian population using polynomial regression models. This cross-sectional study involved 723 pregnant women between 14 and 40 weeks of gestation. Axial measurements of the FNC and FNA were obtained in three measurements and the mean taken as the final value and the 5th, 50th and 95th percentiles for each foetal gestational age (FGA) were calculated. FNC and FNA correlated strongly with FGA, biparietal diameter, abdominal circumference, head circumference, and femoral length. Cubic models fitted the FNC vs FGA, and FNA vs. FGA values, and the mathematical relationships are given as: [Formula: see text] [Formula: see text] [Formula: see text]. Nomograms of FNC and FNA are thus generated. Impact statement The foetal neck circumference (FNC) and foetal neck area (FNA) can serve as predictors of foetal gestational age (FGA) since they correlate strongly and positively with FGA and known biometric parameters. The measurements obtained vary with the population studied. This study provides a nomogram of the FNA and FNC for an African population. The values correlate with that of the Caucasian population up to 32 weeks FGA. Interestingly, FNA and FNC measurements demonstrate high correlation but poor agreement in measurements between sonographers. Even though FNA and FNC could be used as predictors of foetal gestational age, the measurements vary significantly between sonographers. This is attributable to the difficulty in obtaining a satisfactory axial view of foetal neck, which is dependent on foetal presentation.

Developmental origin of the clavicle, and its implications for the evolution of the neck and the paired appendages in vertebrates.

In fish, the pectoral appendage is adjacent to the head, but during vertebrate evolution a long neck region emerged via caudal relocation of the pectoral appendage. The pectoral appendage is comprised of endochondral portions, such as the humerus and the scapula, and a dermal portion, such as the clavicle, that contributes to the shoulder girdle. In the search for clues to the mechanism of the caudal relocation of the pectoral appendage, the cell lineage of the rostral lateral plate mesoderm was analyzed in chickens. It was found that, despite the long neck region in chickens, the origin of the clavicle attached to the head mesoderm ranged between 1 and 14 somite levels. Because the pectoral limb bud and the endochondral pectoral appendage developed on 15-20 and 15-24 somite levels, respectively, the clavicle-forming region corresponds to the embryonic neck, which suggests that the relocation would have been executed by the expansion of the source of the clavicle. The rostral portion of the clavicle-forming region overlaps the source of the cucullaris muscle, embraces the pharyngeal arches caudally, and can be experimentally replaced with the head mesoderm to form the cucullaris muscle, which implies that the mesodermal portion could have been the head mesoderm and that the clavicle would have developed at the head/trunk boundary. The link between the head mesoderm and the presumptive clavicle appears to have been the developmental constraint needed to create the evolutionarily conserved musculoskeletal connectivities characterizing the gnathostome neck. In this sense, the dermal girdle of the ganathostomes would represent the wall of the branchial chamber into which the endochondral pectoral appendage appears to have attached since its appearance in evolution.

Expansion of the neck reconstituted the shoulder-diaphragm in amniote evolution.

The neck acquired flexibility through modifications of the head-trunk interface in vertebrate evolution. Although developmental programs for the neck musculoskeletal system have attracted the attention of evolutionary developmental biologists, how the heart, shoulder and surrounding tissues are modified during development has remained unclear. Here we show, through observation of the lateral plate mesoderm at cranial somite levels in chicken-quail chimeras, that the deep part of the lateral body wall is moved concomitant with the caudal transposition of the heart, resulting in the infolding of the expanded cervical lateral body wall into the thorax. Judging from the brachial plexus pattern, an equivalent infolding also appears to take place in mammalian and turtle embryos. In mammals, this infolding process is particularly important because it separates the diaphragm from the shoulder muscle mass. In turtles, the expansion of the cervical lateral body wall affects morphogenesis of the shoulder. Our findings highlight the cellular expansion in developing amniote necks that incidentally brought about the novel adaptive traits.

Ossification sequence and genetic patterning in the mouse axial skeleton.

We provide novel data on vertebral ontogeny in the mouse, the mammalian model-of-choice for developmental studies. Most previous studies on ossification sequences in mice have focused on pooled elements of the spine (cervicals, thoracics, lumbars, sacrals, and caudals). Here, we contribute data on ossification sequences in the neural arches and centra to provide a comparative basis upon which to evaluate mammalian diversity of the axial skeleton. In attempt to explain the ossification pattern observed, we compared our observations with the phenotype of Cdx over-expresser mice. We use high-resolution X-ray microtomography and clearing and staining techniques to quantify the precise sequential ossification pattern of the mouse spine. We show that micro-CT scans perform better in all cases whereas clearing and staining exhibit sensitivity to the presence of semi-opaque tissue. We observe that the centra of wild-type mice always ossify after neural arches and that the ossification of the neural arches proceeds from two loci. The ossification of the centra appears more complex, especially in the neck where ossification is delayed and does not just follow the order of the vertebrae along the anterior-posterior axis. Our findings also suggest that Cdx genes' expression levels may be involved in the delayed ossification in the neck centra.

The anatomy of nuchal translucency at 10-14 weeks gestation in fetuses with trisomy 21: An incredible medical mystery.

Nuchal translucency (NT) is a hypo-echoic region of subcutaneous fluid accumulation in the posterior neck at the level of the cervical spine between the skin and soft tissues found at 10-14 weeks gestation. This ultrasound finding is important because increased NT measurements place the fetus at increased risk for chromosomal and structural abnormalities. It is a fascinating phenomenon that displays the intersection of anatomy, development, and imaging. In addition, with the ever increasing use of ultrasound in anatomy, NT is a readily demonstrable example of how important ultrasound has become to the practice of medicine. Articles on NT were obtained from OVID database and reviewed for their contribution to an understanding of the anatomical basis of NT. Whereas it is well established that the ultrasound finding of increased NT is a sensitive marker for Trisomy 21 at 10-14 weeks gestation, why this phenomena occurs has yet to be explained. The basis of nuchal edema is most likely multifactorial, a combination of delayed or disturbed lymphangiogenesis, cardiac and vascular abnormalities, and abnormal extracellular matrix components. Further research on the development of the fetal head and neck related to lymphatic development and fluid regulation during 8-14 weeks gestation will enable a greater understanding of how and why increased NT occurs compared to what is currently known. This could lead to early intervention to manage some of the repercussions of Trisomy 21 and other abnormalities related to NT.

Skeletal development in sloths and the evolution of mammalian vertebral patterning.

Mammals show a very low level of variation in vertebral count, particularly in the neck. Phenotypes exhibited at various stages during the development of the axial skeleton may play a key role in testing mechanisms recently proposed to explain this conservatism. Here, we provide osteogenetic data that identify developmental criteria with which to recognize cervical vs. noncervical vertebrae in mammals. Except for sloths, all mammals show the late ossification of the caudal-most centra in the neck after other centra and neural arches. In sloths with 8-10 ribless neck vertebrae, the caudal-most neck centra ossify early, matching the pattern observed in cranial thoracic vertebrae of other mammals. Accordingly, we interpret the ribless neck vertebrae of three-toed sloths caudal to V7 as thoracic based on our developmental criterion. Applied to the unusual vertebral phenotype of long-necked sloths, these data support the interpretation that elements of the axial skeleton with origins from distinct mesodermal tissues have repatterned over the course of evolution.

Suprahyoid neck fascial configuration, especially in the posterior compartment of the parapharyngeal space: a histological study using late-stage human fetuses.

The fascial configuration in the suprahyoid parapharyngeal space was evaluated using semiserial sagittal sections of 15 late-stage human fetal heads. The prevertebral fascia covered the longus colli, longus capitis, and rectus capitis lateralis muscles, but was most evident along the longus colli muscle. The carotid sheath and its extension were located around the internal and external carotid arteries and the lower cranial nerves. The superior cervical ganglion was also inside the sheath. Even near full term, the fetal suprahyoid neck was short, with the jugular foramen and hypoglossal canal located at the posterolateral side of the oropharynx. Thus, the glossopharyngeal and accessory nerves ran across the upper part of the carotid sheath. Fasciae of the stylopharyngeus, styloglossus, and stylohyoideus muscles were attached to and joined the anterosuperior aspect of the carotid sheath. All these neurovascular and muscle sheaths are communicated with the visceral fascia covering the pharynx at multiple sites, and, together, they formed a mesentery-like bundle. This communication bundle was made narrow by the anteriorly protruding longus capitis muscle. The mesentery-like bundle was covered by the posterior marginal fascia of the prestyloid compartment of the parapharyngeal space. The external carotid artery ran on the lateral and posterior sides of the posterior marginal fascia. Consequently, the typical carotid sheath configuration was modified by muscle sheaths from the styloid process, communicated with the visceral fascia and, anteriorly, constituted the posterior margin of the prestyloid space.

[Investigation of ultrasound markers in screening fetal trisomy 21].

OBJECTIVE: To investigate the clinical value of ultrasound markers in screening fetal trisomy 21. METHODS: From Jan. 2001 to Dec. 2011, a retrospective study about sonographic information of 138 fetuses diagnosed as trisomy 21 was taken in the First Affiliated Hospital of Sun Yat-sen University. All fetuses were divided into 3 groups: isolated ultrasound markers, non-isolated ultrasound markers, and isolated structural malformations or other abnormalities. The relationship between trisomy 21 and ultrasound markers as well as structural anomalies or other abnormalities was analyzed. RESULTS: Sonographic anomalies were detected in 132 fetuses (95.7%, 132/138), including ultrasound markers and structural malformations or other abnormalities. One hundred and twenty cases (87.0%, 120/138) had ultrasound markers, 38 (31.7%, 38/120) had one marker and 82 (68.3%, 82/120) had more than one marker (P < 0.01). Fifty-one fetuses (37.0%, 51/138) had isolated ultrasound markers and non-isolated markers were found in 69 fetuses (50.0%, 69/138). Only 12 fetuses (8.7%, 12/138) had isolated structural malformations or other abnormalities. In 20 fetuses on whom the first-trimester ultrasound screening were performed, all had ultrasound markers, 95% (19/20) had thickened nuchal translucency and 55% (11/20) had nasal bone hypoplasia. The most common ultrasound markers on the second-trimester screening were nasal bone hypoplasia, which accounted for 41.9% (52/124) cases, followed by thickened nuchal fold (25.0%, 31/124), short femurs and humerus (24.2%, 30/124), echogenic intracardiac focus (16.1%, 20/124), mild ventriculomegaly (15.3%, 19/124), hyperechoic bowel (12.9%, 16/124), mild renal pyelectasis (12.1%, 15/124). Furthermore, the common structural malformations or other abnormalities were as follows: cardiac defects (33.1%, 41/124), digestive system (26.6%, 33/124). CONCLUSIONS: Ultrasound markers are valuable for screening fetal trisomy 21. The fetuses of trisomy 21 usually had more than one ultrasound markers or associated with other abnormalities. Combinations of ultrasound markers with the results of serum screening and maternal age are necessary for evaluation.

Expression and interaction of muscle-related genes in the lamprey imply the evolutionary scenario for vertebrate skeletal muscle, in association with the acquisition of the neck and fins.

Gnathostomes (jawed vertebrates) possess skeletal muscles with unique functional and developmental features that are absent from cyclostomes-i.e., lamprey and hagfish. These gnathostome-specific traits include the epaxial and hypaxial division of myotomes, paired fin/limb muscles, shoulder girdle muscles, and the muscle associated with the tongue and the neck. Many of these muscles are derived from several rostral somites, specifically from their hypaxial myotomic domains. However, it has not been clarified how the complicated morphology of these muscles was acquired in the evolution of vertebrates. Here we describe the expression of lamprey homologs of transcription factor genes, including a myogenic regulatory factor of the Myod family (MRF), Pax3/7, Lbx, and Zic, which play important roles in the development of ep-/hypaxial somitic muscles in gnathostomes, and show that the ventral portion of lamprey somites is comparable to the ventral dermomyotome in gnathostomes. The supra- and infraoptic muscles, derived from the two anterior somites in the lamprey, are molecularly specified before their extensive invasion into the head region. Of these, the infraoptic myotomes are suggested to represent the cucullaris homologue in the lamprey based on their topographical position in the embryonic pattern. Slightly caudal myotomes in the lamprey give rise to the hypobranchial muscle, the developmental homologue of the gnathostome hypobranchial musculature. The dorsal moieties of the lamprey somites express a Zic gene, which in teleosts specifies the epaxial identities of the somites. These evidences suggest that, although the myotomes in the ancestral jawless vertebrates do not exhibit ep-/hypaxial distinction at the morphological level, their dorsoventral specification would have already been present at gene regulatory levels, prior to the cyclostome-gnathostome divergence, which may have functioned as the key innovation to establish the ep-/hypaxial distinction in gnathostomes.

A hypothesis on the morphologic differences between Unna and Miescher nevi on the head and neck, based on embryologic bases.

Unna and Miescher nevi show very different morphologic features. The main difference is that melanocytes involve mainly the papillary dermis in Unna nevi, whereas they widely penetrate the reticular dermis in Miescher nevi. The reason for this behavior is not totally understood, but anatomical location might play a role, since because Unna nevi are mainly found on the trunk, whereas Miescher nevi are mainly found on the face. We decided to test this hypothesis in relative easy way: dermis from the frontal, temporal, maxillary, and mandibullary regions derives from the neural crest, whereas the dermis of the parietal/occipital regions originates from the paraxial mesoderm (somites and somitomeres). Therefore, we studied the morphology of 137 acquired melanocytic nevi from the head and neck and classified their locations in 7 areas: occipital, temporal, parietal, frontal, face, high neck, and low neck. From such areas, we distinguished 4 groups: area A (parietal + occipital + low neck); area B (face + temporal + frontal + high neck); area 1 (parietal and occipital); and area 2 (temporal and frontal). In region A, 97.30% of the nevi were of Unna type. In region B, 89.00% were of Miescher type. Region A had 76.60% of Unna type nevi, whereas region B had 98.89% of Miescher nevi. In area 1, 100% of the nevi were of Miescher type. In area 2, 86.67% of the nevi were of Unna type. Region 1 had 86.67% of the cranial Unna nevi, whereas region 2 had 100% of the cranial Miescher nevi. Moreover, 90.9% of the nevi from the low neck were of Unna type. In the high neck, 20% of nevi were of Unna type. Finally, 90.90% of Unna nevi were in the low neck, whereas 80% of Miescher nevi were in the high neck. We concluded that these findings supported the hypothesis that the embryologic differences of these areas of head and neck might play a role in the morphology of Unna and Miescher nevi.

Many routes to the same destination: lessons from skeletal muscle development.

The development and differentiation of vertebrate skeletal muscle provide an important paradigm to understand the inductive signals and molecular events controlling differentiation of specific cell types. Recent findings show that a core transcriptional network, initiated by the myogenic regulatory factors (MRFs; MYF5, MYOD, myogenin and MRF4), is activated by separate populations of cells in embryos in response to various signalling pathways. This review will highlight how cells from multiple distinct starting points can converge on a common set of regulators to generate skeletal muscle.

Neural crest origins of the neck and shoulder.

The neck and shoulder region of vertebrates has undergone a complex evolutionary history. To identify its underlying mechanisms we map the destinations of embryonic neural crest and mesodermal stem cells using Cre-recombinase-mediated transgenesis. The single-cell resolution of this genetic labelling reveals cryptic cell boundaries traversing the seemingly homogeneous skeleton of the neck and shoulders. Within this assembly of bones and muscles we discern a precise code of connectivity that mesenchymal stem cells of both neural crest and mesodermal origin obey as they form muscle scaffolds. The neural crest anchors the head onto the anterior lining of the shoulder girdle, while a Hox-gene-controlled mesoderm links trunk muscles to the posterior neck and shoulder skeleton. The skeleton that we identify as neural crest-derived is specifically affected in human Klippel-Feil syndrome, Sprengel's deformity and Arnold-Chiari I/II malformation, providing insights into their likely aetiology. We identify genes involved in the cellular modularity of the neck and shoulder skeleton and propose a new method for determining skeletal homologies that is based on muscle attachments. This has allowed us to trace the whereabouts of the cleithrum, the major shoulder bone of extinct land vertebrate ancestors, which seems to survive as the scapular spine in living mammals.

The relationship between maternal body mass, smoking status and ethnicity and first trimester nuchal translucency thickness.

OBJECTIVE: To investigate the existence of a relationship between maternal body mass, maternal ethnicity and maternal smoking status and nuchal translucency (NT) in the first trimester of pregnancy. METHODS: NT measurements from 130 339 euploid, singleton pregnancies were converted to NT multiples of the median (MoM) and delta NT using expected medians determined using regression analysis. Relationships between maternal body mass index (BMI), maternal weight, maternal ethnicity and maternal smoking status and NT MoM and delta NT were examined. RESULTS: NT increased with gestational age. Uncorrected NT MoM and delta NT demonstrated small but significant positive relationships with either maternal BMI or maternal weight. Both NT MoM and delta NT were slightly, but significantly, increased in smokers compared to non-smokers and Afro-Caribbean compared to Caucasians, and slightly, but significantly, decreased in Asians compared to Caucasians. CONCLUSION: Although statistically significant, all the changes reported are likely to be too small to be relevant in terms of correcting in prenatal screening.

Differential proteomics analysis of amniotic fluid in pregnancies of increased nuchal translucency with normal karyotype.

OBJECTIVES: To investigate the functional roles of differentially expressed proteins in amniotic fluid supernatant (AFS) from normal karyotype pregnancies with increased nuchal translucency (NT). METHODS: AFS from fetuses with increased NT (>3.4 mm, N = 14) and control (<0.7 mm, N = 14) were analyzed by two-dimensional electrophoresis and in-gel digestion to identify the difference of expressed proteins between both groups. Targeted proteins were confirmed by western blot and ELISA. The roles of biological networks in pathophysiology of NT were determined using MetaCore mapping. RESULTS: Levels of apolipoprotein-A1 (Entrez Gene ID 335), alpha-1 antitrypsin (SERPINA1, ID 5265) and prolactin (ID 5617) were significantly decreased in AFS of fetuses with increased NT compared with those in controls. According to Gene Ontology terms, biological processes of functional networks were mainly involved in steroid metabolism. On the basis of the database of MetaCore, these proteins are considered as the potential biomarkers of cardiovascular disorders. The prediction of tissue distribution from this network in fetal organs such as liver, skin, and kidney supported that these three proteins may play different roles between two groups. CONCLUSION: The combination of using quantitative proteomics and functional network analysis could integrally analyze the pathophysiology of fetuses with increased NT.