Altered placental immune cell composition and gene expression with isolated fetal spina bifida.

PROBLEM: Fetal spina bifida (SB) is more common in pregnant people with folate deficiency or anomalies of folate metabolism. It is also known that fetuses with SB have a higher risk of low birthweight, a condition that is typically placental-mediated. We therefore hypothesized that fetal SB would associate with altered expression of key placental folate transporters and an increase in Hofbauer cells (HBCs), which are folate-dependent placental macrophages. METHOD OF STUDY: Folate receptor-α (FRα), proton coupled folate receptor (PCFT), and reduced folate carrier (RFC) protein localization and expression (immunohistochemistry) and HBC phenotypes (HBC abundance and folate receptor-ß [FRß] expression; RNA in situ hybridization) were assessed in placentae from fetuses with SB (cases; n = 12) and in term (n = 10) and gestational age (GA) - and maternal body mass index - matched (n = 12) controls without congenital anomalies. RESULTS: Cases had a higher proportion of placental villous cells that were HBCs (6.9% vs. 2.4%, p = .0001) and higher average HBC FRß expression (3.2 mRNA molecules per HBC vs. 2.3, p = .03) than GA-matched controls. HBCs in cases were largely polarized to a regulatory phenotype (median 92.1% of HBCs). In sex-stratified analyses, only male cases had higher HBC levels and HBC FRß expression than GA-matched controls. There were no differences between groups in the total percent of syncytium and stromal cells that were positive for FRα, PCFT, or RFC protein immunolabeling. CONCLUSIONS: HBC abundance and FRß expression by HBCs are increased in placentae of fetuses with SB, suggesting immune-mediated dysregulation in placental phenotype, and could contribute to SB-associated comorbidities.

Automated detection of microscopic placental features indicative of maternal vascular malperfusion using machine learning.

INTRODUCTION: Hypertensive disorders of pregnancy (HDP) and fetal growth restriction (FGR) are common obstetrical complications, often with pathological features of maternal vascular malperfusion (MVM) in the placenta. Currently, clinical placental pathology methods involve a manual visual examination of histology sections, a practice that can be resource-intensive and demonstrates moderate-to-poor inter-pathologist agreement on diagnostic outcomes, dependant on the degree of pathologist sub-specialty training. METHODS: This study aims to apply machine learning (ML) feature extraction methods to classify digital images of placental histopathology specimens, collected from cases of HDP [pregnancy induced hypertension (PIH), preeclampsia (PE), PE + FGR], normotensive FGR, and healthy pregnancies, according to the presence or absence of MVM lesions. 159 digital images were captured from histological placental specimens, manually scored for MVM lesions (MVM- or MVM+) and used to develop a support vector machine (SVM) classifier model, using features extracted from pre-trained ResNet18. The model was trained with data augmentation and shuffling, with the performance assessed for patch-level and image-level classification through measurements of accuracy, precision, and recall using confusion matrices. RESULTS: The SVM model demonstrated accuracies of 70 % and 79 % for patch-level and image-level MVM classification, respectively, with poorest performance observed on images with borderline MVM presence, as determined through post hoc observation. DISCUSSION: The results are promising for the integration of ML methods into the placental histopathological examination process. Using this study as a proof-of-concept will lead our group and others to carry ML models further in placental histopathology.

Placental Pathology and Pregnancy Complications.

Placental pathology assessment following delivery provides an opportunity to identify the presence and type of disease that can mediate major obstetrical complications, especially in cases where the fetus is growth-restricted, born premature, or stillborn, or if the mother suffers from severe hypertensive morbidities [...].

Synoptic Reporting in Clinical Placental Pathology: A Preliminary Investigation Into Report Findings and Interobserver Agreement.

INTRODUCTION: Placental pathology is key for investigating adverse pregnancy outcomes, however, lack of standardization in reporting has limited clinical utility. We evaluated a novel placental pathology synoptic report, comparing its robustness to narrative reports, and assessed interobserver agreement. METHODS: 100 singleton placentas were included. Histology slides were examined by 2 senior perinatal pathologists and 2 pathology residents using a synoptic report (32 lesions). Historical narrative reports were compared to synoptic reports. Kappa scores were calculated for interobserver agreement between senior, resident, and senior vs resident pathologists. RESULTS: Synoptic reporting detected 169 (51.4%) lesion instances initially not included in historical reports. Amongst senior pathologists, 64% of all lesions examined demonstrated fair-to-excellent agreement (Kappa ≥0.41), with only 26% of Kappas ≥0.41 amongst those examined by resident pathologists. Well-characterized lesions (e.g., chorioamnionitis) demonstrated higher agreement, with lower agreement for uncommon lesions and those previously shown to have poor consensus. DISCUSSION: Synoptic reporting is one proposed method to address issues in placenta pathology reporting. The synoptic report generally identifies more lesions compared to the narrative report, however clinical significance remains unclear. Interobserver agreement is likely related to differential in experience. Further efforts to improve overall standardization of placenta pathology reporting are needed.

Proteomics Profiling of Stool Samples from Preterm Neonates with SWATH/DIA Mass Spectrometry for Predicting Necrotizing Enterocolitis.

Necrotizing enterocolitis (NEC) is a life-threatening condition for premature infants in neonatal intensive care units. Finding indicators that can predict NEC development before symptoms appear would provide more time to apply targeted interventions. In this study, stools from 132 very-low-birth-weight (VLBW) infants were collected daily in the context of a multi-center prospective study aimed at investigating the potential of fecal biomarkers for NEC prediction using proteomics technology. Eight of the VLBW infants received a stage-3 NEC diagnosis. Stools collected from the NEC infants up to 10 days before their diagnosis were available for seven of them. Their samples were matched with those from seven pairs of non-NEC controls. The samples were processed for liquid chromatography-tandem mass spectrometry analysis using SWATH/DIA acquisition and cross-compatible proteomic software to perform label-free quantification. ROC curve and principal component analyses were used to explore discriminating information and to evaluate candidate protein markers. A series of 36 proteins showed the most efficient capacity with a signature that predicted all seven NEC infants at least a week in advance. Overall, our study demonstrates that multiplexed proteomic signature detection constitutes a promising approach for the early detection of NEC development in premature infants.

Maternal Underweight and Obesity Are Associated with Placental Pathologies in Human Pregnancy.

Maternal underweight and obesity are prevalent conditions, associated with chronic, low-grade inflammation, poor fetal development, and long-term adverse outcomes for the child. The placenta senses and adapts to the pregnancy environment in an effort to support optimal fetal development. However, the mechanisms driving these adaptations, and the resulting placental phenotypes, are poorly understood. We hypothesised that maternal underweight and obesity would be associated with increased prevalence of placental pathologies in term and preterm pregnancies. Data from 12,154 pregnancies were obtained from the Collaborative Perinatal Project, a prospective cohort study conducted from 1959 to 1974. Macro- and microscopic placental pathologies were analysed across maternal prepregnancy body mass index (BMI) to assess differences in the presence of pathologies among underweight, overweight, and obese BMI groups compared to normal weight reference BMI at term and preterm. Placental pathologies were also assessed across fetal sex. Pregnancies complicated by maternal obesity had placentae with increased fetal inflammation at preterm, and increased inflammation of maternal gestational tissues at term. In term pregnancies, increasing maternal BMI associated with increased maternal vascular malperfusion (MVM), odds of an appropriately mature placenta for gestational age, and placental weight, and decreased placental efficiency. Male placentae, independent of maternal BMI, had increased inflammation, MVM, and placental efficiency than female placentae, particularly at term. Maternal underweight and obesity are not inert conditions for the placenta, and the histomorphological changes driven by suboptimal maternal BMI may serve as indicators of adversities experienced in utero and potential predictors of future health trajectories.

Placental Pathology as a Tool to Identify Women for Postpartum Cardiovascular Risk Screening following Preeclampsia: A Preliminary Investigation.

Preeclampsia (PE) is associated with an increased risk of cardiovascular disease (CVD) in later life. Postpartum cardiovascular risk screening could identify patients who would benefit most from early intervention and lifestyle modification. However, there are no readily available methods to identify these high-risk women. We propose that placental lesions may be useful in this regard. Here, we determine the association between placental lesions and lifetime CVD risk assessed 6 months following PE. Placentas from 85 PE women were evaluated for histopathological lesions. At 6 months postpartum, a lifetime cardiovascular risk score was calculated. Placental lesions were compared between CVD risk groups and the association was assessed using odds ratios. Multivariable logistic regression was used to develop prediction models for CVD risk with placental pathology. Placentas from high-risk women had more severe lesions of maternal vascular malperfusion (MVM) and resulted in a 3-fold increased risk of screening as high-risk for CVD (OR 3.10 (1.20-7.92)) compared to women without these lesions. MVM lesion severity was moderately predictive of high-risk screening (AUC 0.63 (0.51, 0.75); sensitivity 71.8% (54.6, 84.4); specificity 54.7% (41.5, 67.3)). When clinical parameters were added, the model's predictive performance improved (AUC 0.73 (0.62, 0.84); sensitivity 78.4% (65.4, 87.5); specificity 51.6% (34.8, 68.0)). The results suggest that placenta pathology may provide a unique modality to identify women for cardiovascular screening.

Thrombospondin-1 Plays a Major Pathogenic Role in Experimental and Human Bronchopulmonary Dysplasia.

Rationale: Extremely preterm infants develop bronchopulmonary dysplasia (BPD), a chronic lung injury that lacks effective treatment. TSP-1 (thrombospondin-1) is an antiangiogenic protein that activates TGF-ß1 (transforming growth factor-ß1), a cytokine strongly linked to both experimental and human BPD. Objectives:1) To examine effects of inhibiting TSP-1-mediated TGF-ß1 activation (LSKL [leucine-serine-lysine-leucine]) in neonatal rats with bleomycin-induced lung injury; 2) to examine effects of a TSP-1 mimic (ABT-510) on lung morphology; and 3) to determine whether TSP-1 and related signaling peptides are increased in lungs of human preterm infants at risk for BPD. Methods: From Postnatal Days 1 to 14, rat pups received daily intraperitoneal bleomycin (1 mg/kg) or vehicle and were treated with daily subcutaneous LSKL (20 mg/kg) or vehicle alone. Separate animals were treated with vehicle or ABT-510 (30 mg/kg/d). Paraffin-embedded lung tissues from 47 autopsies (controls; death <28 d, n = 30 and BPD at risk; death ⩾28 d, n = 17) performed on infants born <29 completed weeks' gestation were semiquantified for injury markers (collagen, macrophages, and 3-nitrotyrosine), TSP-1, and TGF-ß1. Measurements and Main Results: Bleomycin or ABT-510 increased lung TGF-ß1 activity and macrophage influx, caused pulmonary hypertension, and led to alveolar and microvascular hypoplasia. Treatment with LSKL partially prevented abnormal lung morphology secondary to bleomycin. Lungs from human infants at risk for BPD had increased contents of TSP-1 and TGF-ß1 when compared with controls. TGF-ß1 content correlated with markers of lung injury. Conclusions: TSP-1 inhibits alveologenesis in neonatal rats, in part via the upregulated activity of TGF-ß1. Observations in human lungs suggest a similar pathogenic role for TSP-1 in infants at risk for BPD.

Lipocalin-2 and calprotectin as stool biomarkers for predicting necrotizing enterocolitis in premature neonates.

BACKGROUND: Necrotizing enterocolitis (NEC) is a major challenge for premature infants in neonatal intensive care units and efforts toward the search for indicators that could be used to predict the development of the disease have given limited results until now. METHODS: In this study, stools from 132 very low birth weight infants were collected daily in the context of a multi-center prospective study aimed at investigating the potential of fecal biomarkers for NEC prediction. Eight infants (~6%) received a stage 3 NEC diagnosis. Their stools collected up to 10 days before diagnosis were included and matched with 14 non-NEC controls and tested by ELISA for the quantitation of eight biomarkers. RESULTS: Biomarkers were evaluated in all available stool samples leading to the identification of lipocalin-2 and calprotectin as the two most reliable predicting markers over the 10-day period prior to NEC development. Pooling the data for each infant confirmed the significance of lipocalin-2 and calprotectin, individually and in combination 1 week in advance of the NEC clinical diagnosis. CONCLUSIONS: The lipocalin-2 and calprotectin tandem represents a significant biomarker signature for predicting NEC development. Although not yet fulfilling the "perfect biomarker" criteria, it represents a first step toward it. IMPACT: Stool biomarkers can be used to predict NEC development in very low birth weight infants more than a week before the diagnosis. LCN2 was identified as a new robust biomarker for predicting NEC development, which used in conjunction with CALPRO, allows the identification of more than half of the cases that will develop NEC in very low birth weight infants. Combining more stool markers with the LCN2/CALPRO tandem such as PGE2 can further improve the algorithm for the prediction of NEC development.

Preterm Birth Associates With Increased Placental Expression of MDR Transporters Irrespective of Prepregnancy BMI.

CONTEXT: Preterm birth (PTB) and suboptimal prepregnancy body mass index (BMI) operate through inflammatory pathways to impair fetoplacental development. Placental efflux transporters mediate fetal protection and nutrition; however, few studies consider the effect of both PTB and BMI on fetal protection. We hypothesized that PTB would alter the expression of placental multidrug resistance (MDR) transporters and selected proinflammatory cytokines, and that maternal underweight and obesity would further impair placental phenotype. OBJECTIVE: To determine whether placental MDR transporters P-glycoprotein (P-gp, encoded by ABCB1) and breast cancer resistance protein (BCRP/ABCG2), and proinflammatory cytokine levels are altered by PTB and maternal BMI. METHODS: A cross-sectional study was conducted to assess the effect of PTB (with/without chorioamnionitis), or the effect of maternal prepregnancy BMI on placental MDR transporter and interleukin (IL)-6 and -8 expression in 60 preterm and 36 term pregnancies. RESULTS: ABCB1 expression was increased in preterm compared to term placentae (P = .04). P-gp (P = .008) and BCRP (P = .01) immunolabeling was increased among all preterm compared to term placentae, with P-gp expression further increased in preterm pregnancies with chorioamnionitis (PTC, P = .007). Placental IL-6 mRNA expression was decreased in PTC compared to term placentae (P = .0005) and PTC associated with the greatest proportion of anti-inflammatory medications administered during pregnancy. Maternal BMI group did not influence placental outcomes. CONCLUSION: PTB and infection, but not prepregnancy BMI, alter placental expression of MDR transporters and IL-6. This may have implications for fetal exposure to xenobiotics that may be present in the maternal circulation in pregnancies complicated by PTB.

Isolated fetal neural tube defects associate with increased risk of placental pathology: Evidence from the Collaborative Perinatal Project.

INTRODUCTION: Neural tube defects (NTDs) are amongst the most common congenital anomalies and are associated with significant postnatal morbidity, but also with a higher incidence of low birthweight and fetal growth restriction. Despite the placenta being a critical determinant of fetal growth, placental development has not been extensively studied in fetuses with NTDs. METHODS: We performed a matched case-cohort study using data from the Collaborative Perinatal Project to assess the risk of placental pathology in pregnancies with an isolated fetal NTD (cases; n = 74) compared to those without any congenital anomalies (controls; n = 148). We hypothesised that cases would be at an increased risk of placental pathology compared to controls. Data were analysed using adjusted generalized linear and nominal logistic regression models. Results are presented as adjusted ß or adjusted odds ratio (aOR; 95% confidence interval). RESULTS: Cases had lower placental weight (ß = -22.2 g [-37.8 to -6.6]), surface area (ß = -9.6 cm2 [-18.3 to -1.0]) and birth length z-scores (ß = -0.4 [-0.7 to -0.001]) compared to controls. Cases were more likely to have a single umbilical artery (vs. two; 6 [8.1%] vs. 1 [0.7%]; aOR = 301 [52.6-1726]), placental hypermaturity (9 [12.2%] vs. 5 [3.4%]; aOR = 6.8 [3.1-14.7]), many (vs. few) Hofbauer cells (9 [12.2%] vs. 7 [4.7%]; aOR = 3.02 [1.2-7.3]), and stromal fibrosis (9 [12.2%] vs. 10 [6.8%]; aOR = 3.0 [1.4-6.3]) in placental terminal villi compared to controls. CONCLUSIONS: Fetuses with isolated NTDs may be at increased risk of placental pathology, which could be contributing to poor fetal growth in these pregnancies and subsequent postnatal morbidities.

Fibrinogen-Like Protein 2-Associated Transcriptional and Histopathological Features of Immunological Preeclampsia.

Preeclampsia is a multifactorial hypertensive disorder of pregnancy, with variable presentation in both maternal and fetal factors, such that no treatment or marker is currently universal to all cases. Here, we demonstrate that the prothrombinase and immunomodulatory secreted factor FGL-2 (fibrinogen-like protein 2) is differentially expressed across previously characterized gene expression clusters containing clinically relevant disease subtypes. FGL2 is low in a cluster consistent with the traditional paradigm of the pathology of preeclampsia (canonical preeclampsia) and high in a cluster exhibiting evidence of immune activation (immunological preeclampsia). We show that it is part of an immunoregulatory gene module integral to the transcriptional profile and placental pathology specific to immunological preeclampsia. We determine that FGL2 associates positively with chronic inflammation lesions of the placenta while associating negatively with maternal vascular malperfusion lesions. The transcriptional profiles of maternal vascular malperfusion lesions show downregulation of FGL2 and upregulation of previously investigated preeclampsia biomarkers, such as FLT1 (Fms Related Receptor Tyrosine Kinase 1) and ENG (endoglin). Conversely, the profiles of chronic inflammation lesions show an interesting downregulation of these genes, but an upregulation of FGL2 and of FGL2-correlated immunoregulatory genes, suggesting it is upregulated downstream of major inflammatory mediators such as TNF (tumor necrosis factor)-α and IFN (interferon)-γ, hallmarks of the immunological preeclampsia subtype. This work, overall, demonstrates that FGL-2 expression levels in the term placenta reflect the unique pathophysiology that leads to immunological preeclampsia, leading to its potential as a subtype-specific biomarker.

Neonatal necrotizing enterocolitis: a case series examining clinical diagnosis with discrepant versus concordant autopsy results.

OBJECTIVE: The objective of this study is to determine whether rapidity of death in necrotizing enterocolitis (NEC) increased odds of discordance between clinical and pathological diagnosis. STUDY DESIGN: Retrospective case-series study including preterm infants admitted to the NICU. RESULTS: Twenty-two infants met the selection criteria. Gross pathologic evidence of NEC was present in 1/6 cases (17%) where demise occurred <12 h after onset of symptoms, 3/5 cases (60%) within 12-24 h, and 8/11 cases (73%) in >24 h. Histological evidence of necrosis was present in 4/6 (67%) cases when death occurred <12 h, 4/5 (80%) in 12-24 h, and 9/11 (82%) in >24 h. The percentage with gross pathologic evidence showed a monotonic trend (P = 0.031), while the trend was less clear for histologic findings (P = 0.496). CONCLUSION: Pathologic features of cell death may not have had sufficient time to develop. This study could reassure both healthcare providers and families when pathologic and clinical diagnoses are not consistent.

Gastroschisis Is Associated With Placental Delayed Villous Maturation.

Gastroschisis is a congenital abnormality characterized by visceral herniation through an abdominal wall defect. While the cause of gastroschisis is unknown, it has been linked to risk factors including young maternal age, smoking, and alcohol use during pregnancy. To date, the only established placental correlate is amniocyte vacuolization. Based on our clinical experience, we hypothesized that delayed villous maturation (DVM) is also associated with gastroschisis. We conducted a retrospective slide review of 23 placentas of neonates with gastroschisis. Additionally, we selected 2 control groups of placentas: 1 with a previous diagnosis of DVM and 1 with normal villous morphology. All placentas were randomized and reviewed by 2 perinatal pathologists, who were blinded to the group; DVM and amniocyte vacuolization were assessed. Gastroschisis was associated with increased placental DVM in 65.2% of cases (vs 13.6% of controls; P = .0007) and increased amniocyte vacuolization in 52.2% of cases (vs 9.1% of controls; P = .003) compared to the control group. Based on the normal and DVM groups, kappa agreement between current slide review and initial pathology diagnosis was 0.419, indicating moderate agreement. Our study shows that gastroschisis is associated with placental DVM. This association may be due to (1) a common upstream factor contributing to both gastroschisis and DVM or (2) DVM may be a consequence of the altered placental and amniotic environment in the context of gastroschisis.

Incorporating Transition-Affirming Language into Anatomical Pathology Reporting for Gender Affirmation Surgery.

Background: The use of inclusive terminology in health records continues to be a challenge for transgender, gender-diverse, and nonbinary peoples. When patients access electronic health records, laboratory results, including pathology reports, are among the most frequently viewed items. There has been limited discussion of transgender care within laboratory medicine, despite its role in providing written pathology reports after gender-affirming surgery. Proposal: This group proposes inclusive diagnostic terminology for pathology reporting and puts forward recommendations for procedural descriptions in the pathology report. Finally, we highlight pathological information that should be included in a report that has future cancer screening or diagnostic consequences.

Both "canonical" and "immunological" preeclampsia subtypes demonstrate changes in placental immune cell composition.

Our prior work investigating the heterogeneity of preeclampsia identified multiple placental subtypes of this disorder, including a "canonical" group with maternal vascular malperfusion and an "immunological" group with signs of allograft rejection. Here, we perform a pilot immunohistochemistry study to investigate if an increase in infiltrating maternal immune cells is contributing to the "immunological" pathology subtype. This revealed an enrichment of monocytes and/or neutrophils (CD68 + and MPO+ cells) in the intervillous space of these placentas. Surprisingly, "canonical" samples also demonstrated a significant result, with decreased CD68 staining. As such, further immunohistochemistry to assess immune contributions in preeclampsia subtypes is warranted.

Pilomatrixoma of the ocular adnexa: report of 3 cases with variations in the histopathological findings.

OBJECTIVE: To report the clinical and variations in the histopathological features of pilomatrixoma of the ocular adnexa in 3 young individuals. DESIGN: A retrospective case series was performed with clinical, histological, and immunohistochemical analysis. PARTICIPANTS: Case 1 is an 18-year-old male who presented with a reddish-blue swelling under the left eyebrow. The lesion measured 2 × 1 cm. Case 2 is a 2-year-old female who presented with a reddish-blue nodule inferior to the right eyebrow with telangiectatic vessels. The lesion measured 6 × 4 × 4 mm. Case 3 is a 14-year-old female who presented with a subcutaneous lesion under the right upper eyebrow with fluctuating inflammation. The lesion measured 12 × 3 × 2 mm. Histopathological examination of case 1 disclosed peripheral basaloid cells and central shadow cells containing calcific foci, separated by a transition zone. In case 2, histopathological analysis revealed central calcific foci in islands of shadow cells with more peripheral basaloid cells. In case 3, we observed numerous clusters of shadow cells with focal calcifications, as well as basaloid cells in a disorganized configuration. CONCLUSION: Pilomatrixoma is an uncommon benign skin neoplasm originating from the matrix of the hair root. We describe a spectrum of histopathological findings in pilomatrixoma of the ocular adnexal in 3 young individuals.

Recurrent Placental Transcriptional Profile With a Different Histological and Clinical Presentation: A Case Report.

Statistically, patients with severe pregnancy complications are at risk of recurrent complications, but it is less understood if patients present with similar or different placental pathologies in subsequent pregnancies. In this case report, we describe 2 consecutive adverse pregnancies in the same woman 4 years apart. The first pregnancy was diagnosed as early-onset preeclampsia and hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome, with placental maternal vascular malperfusion features, such as syncytial knots and accelerated villous maturity. In contrast, the second pregnancy was associated with normotensive fetal growth restriction and placental "immunological" lesions, such as massive perivillous fibrin deposition and chronic intervillositis. However, based on the expression of FLT1, LIMCH1, and TAP1 by quantitative polymerase chain reaction, the placentas from both pregnancies were found to exhibit an "immunological" transcriptional signature. This suggests that this small panel of gene expression markers may be able to predict the future reoccurrence of an immunological placental pathology despite no histological evidence within the first pregnancy. These results call for more studies looking at paired pregnancies of individuals with recurrent obstetric complications and confirm the importance of assessing matched transcriptional and histopathological placental information.

Neu-Laxova syndrome presenting prenatally with increased nuchal translucency and cystic hygroma: The utility of exome sequencing in deciphering the diagnosis.

Neu-Laxova syndrome (NLS) is a lethal autosomal recessive microcephaly syndrome associated with intrauterine growth restriction (IUGR) and multiple congenital anomalies. Clinical features include central nervous system malformations, joint contractures, ichthyosis, edema, and dysmorphic facial features. Biallelic pathogenic variants in either the PHGDH or PSAT1 genes have been shown to cause NLS. Using exome sequencing, we aimed to identify the underlying genetic diagnosis in three fetuses (from one family) with prenatal skin edema, severe IUGR, micrognathia, renal anomalies, and arthrogryposis and identified a homozygous c.1A>C (p.Met1?, NM_006623.3) variant in the PHGDH gene. Loss of the translation start codon is a novel genetic mechanism for the development of NLS. Prenatal diagnosis of NLS is challenging and few reports describe the fetal pathology. Fetal neuropathologic examination revealed: delayed brain development, congenital agenesis of the corticospinal tracts, and hypoplasia of the hippocampus, cerebellum and brainstem. Each pregnancy also showed increased nuchal translucency (NT) or cystic hygroma. While NLS is rare, it may be a cause of recurrent increased NT/cystic hygroma. This finding provides further support that cystic hygroma has many different genetic causes and that exome sequencing may shed light on the underlying genetic diagnoses in this group of prenatal patients.