Case report: Antenatal diagnostic of a polymalformative syndrome due to biallelic BRCA2 mutations.

Testing the partner of a BRCA2 carrier must always be discussed. If both members of the couple are BRCA2 carriers, they should be informed about the high risks of polymalformative syndromes.

Expanding the genotypic and phenotypic spectrum of severe serine biosynthesis disorders.

Serine biosynthesis disorders comprise a spectrum of very rare autosomal recessive inborn errors of metabolism with wide phenotypic variability. Neu-Laxova syndrome represents the most severe expression and is characterized by multiple congenital anomalies and pre- or perinatal lethality. Here, we present the mutation spectrum and a detailed phenotypic analysis in 15 unrelated families with severe types of serine biosynthesis disorders. We identified likely disease-causing variants in the PHGDH and PSAT1 genes, several of which have not been reported previously. Phenotype analysis and a comprehensive review of the literature corroborates the evidence that serine biosynthesis disorders represent a continuum with varying degrees of phenotypic expression and suggest that even gradual differences at the severe end of the spectrum may be correlated with particular genotypes. We postulate that the individual residual enzyme activity of mutant proteins is the major determinant of the phenotypic variability, but further functional studies are needed to explore effects at the enzyme protein level.

Finding vacuolated lymphocytes in fetal effusions improves the prenatal diagnosis of lysosomal storage diseases.

OBJECTIVES: There are many causes of fetal effusions, including the rare lysosomal storage diseases (LSDs). Vacuolated lymphocytes (VLs) are found in the blood of infants with LSDs, and their presence in fetal effusion could increase the risk of underlying LSD. METHODS: Between 2006 and 2018, all fetal effusions samples from 43 fetal multidisciplinary centers were referred to a single laboratory. Cells were counted, and, if observed, VLs were categorized and counted. Screening for LSDs was performed by metabolite analyses on amniotic fluid supernatant. The diagnosis of an LSD was confirmed by measuring the activity of the corresponding enzyme and/or mutation analysis. RESULTS: Our laboratory received 614 ascitic fluids and 280 pleural fluids sampled between 22 and 33 weeks of gestation. The final diagnosis was LSD in 16 cases (1.8%). VLs were reported in all these 16 cases, in a mix of lymphocytes with and without vacuoles. Vacuoles in VLs varied in size and number. In most cases, VLs were easy to recognize, with numerous, large, round, well-defined vacuoles, but in three cases of LSDs, VLs were atypical. CONCLUSION: The finding of VLs in fetal effusions is an inexpensive first-line test that may help to prioritize biochemical and genetic tests for LSDs.

Duplicated distal phalanx of thumb or hallux in trisomy 13: A recurrent feature in a series of 42 fetuses.

Trisomy 13 or Patau syndrome (PS) is a well-known aneuploidy characterized by a polymalformative syndrome. We described a large series of fetuses with PS and compared them with cases described in the literature, most of which were live-born. In all, 42 fetuses, aged from 14 to 41 gestational weeks (GW), were examined. The main defects observed were similar to those described in live-born patients: congenital heart defects (76%), holoprosencephaly spectrum anomalies including arhinencephaly and hypotelorism (74%), urinary tract anomalies (71%), ear anomalies (69%), postaxial polydactyly (67%), anogenital anomalies (60%), anophthalmos, and/or microphthalmos (53%), brachycephaly (45%), and oro-facial clefts (45%). A duplication or triplication of at least one distal phalanx of the thumb or hallux was present in 38% of fetuses. This sign has only been reported previously in one patient in the literature. Fetal examination in trisomy 13, is thus, useful to complete the phenotype or to orient diagnosis toward trisomy 13 in the absence of cytogenetic analysis.

Severe Phenotype of Cutis Laxa Type 1B with Antenatal Signs due to a Novel Homozygous Nonsense Mutation in EFEMP2.

EFEMP2 mutations are known to be responsible for autosomal recessive cutis laxa type 1B (ARCL1B), a rare multisystem disease affecting skin, skeleton, and vascular structures. We report 2 additional related cases of ARCL1B of particular severity leading to termination of pregnancy. Cardinal signs of this connective tissue disease were already seen during the second trimester of pregnancy, then confirmed and clarified at autopsy. Anomalies included cutis laxa, arachnodactyly, clubfoot, wormian bones, moderate bowing of long bones with slender bone trabeculae, rib fractures, undermuscularized diaphragm, hiatal hernia, and arterial tortuosity with thick vascular walls and disorganized elastic fibers. Sequencing of the EFEMP2 gene revealed a novel homozygous nonsense mutation: c.639C>A (p.Cys213*). We performed a thorough histological analysis and discuss differential diagnoses, genotype-phenotype correlations, and the challenge of prenatal diagnosis of this disease.

Growth Restriction, Osteopenia, Placental Massive Perivillous Fibrin Deposition With (or Without) Intervillous Histiocytes and Renal Tubular Dysgenesis-An Emerging Complex.

We describe a case of a pregnancy complicated by early onset asymmetric growth restriction with anhydramnios with termination occurring at 21 weeks. Fetal autopsy showed demineralization of bones and renal tubular dysgenesis. Placental pathology showed features of massive perivillous fibrin deposition and chronic histiocytic intervillositis. We review prior documentation of this association and briefly discuss potential pathogenesis.

TRAP Sequence in Monochorionic/Monoamniotic (MC/MA) Discordant Twins: Two Cases Treated with Fetoscopic Laser Surgery.

INTRODUCTION: Ablation of the acardiac twin umbilical cord in the TRAP protects the normal donor twin. MATERIALS AND METHODS: Two case descriptions, one of interstitial laser photocoagulation and one of laser umbilical cord occlusion (L-UCO) of the acardiac twin in monochorionic monoamniotic pregnancies are reported. RESULTS: L-UCO in two pregnancies with TRAP syndrome in the second trimester resulted in intrauterine fetal death in both cases after 1 month. Case 1 had no detectable cause of fetal death. Case 2 had rupture of the amniotic sac causing anhydramnios and acute chorioamnionitis. A groove on the umbilical cord of the normal twin indicated a cord stricture due to cord entanglement. CONCLUSION: Our experience confirms that the best timing and optimal treatment of MC/MA twins complicated by TRAP sequence still remains a controversial clinical issue. Cord entanglement may continue be a potential clinical risk factor for adverse perinatal outcome even after ablation therapy.

Novel NEK8 Mutations Cause Severe Syndromic Renal Cystic Dysplasia through YAP Dysregulation.

Ciliopathies are a group of genetic multi-systemic disorders related to dysfunction of the primary cilium, a sensory organelle present at the cell surface that regulates key signaling pathways during development and tissue homeostasis. In order to identify novel genes whose mutations would cause severe developmental ciliopathies, >500 patients/fetuses were analyzed by a targeted high throughput sequencing approach allowing exome sequencing of >1200 ciliary genes. NEK8/NPHP9 mutations were identified in five cases with severe overlapping phenotypes including renal cystic dysplasia/hypodysplasia, situs inversus, cardiopathy with hypertrophic septum and bile duct paucity. These cases highlight a genotype-phenotype correlation, with missense and nonsense mutations associated with hypodysplasia and enlarged cystic organs, respectively. Functional analyses of NEK8 mutations in patient fibroblasts and mIMCD3 cells showed that these mutations differentially affect ciliogenesis, proliferation/apoptosis/DNA damage response, as well as epithelial morphogenesis. Notably, missense mutations exacerbated some of the defects due to NEK8 loss of function, highlighting their likely gain-of-function effect. We also showed that NEK8 missense and loss-of-function mutations differentially affect the regulation of the main Hippo signaling effector, YAP, as well as the expression of its target genes in patient fibroblasts and renal cells. YAP imbalance was also observed in enlarged spheroids of Nek8-invalidated renal epithelial cells grown in 3D culture, as well as in cystic kidneys of Jck mice. Moreover, co-injection of nek8 MO with WT or mutated NEK8-GFP RNA in zebrafish embryos led to shortened dorsally curved body axis, similar to embryos injected with human YAP RNA. Finally, treatment with Verteporfin, an inhibitor of YAP transcriptional activity, partially rescued the 3D spheroid defects of Nek8-invalidated cells and the abnormalities of NEK8-overexpressing zebrafish embryos. Altogether, our study demonstrates that NEK8 human mutations cause major organ developmental defects due to altered ciliogenesis and cell differentiation/proliferation through deregulation of the Hippo pathway.

Inversion duplication deletions involving the long arm of chromosome 13: phenotypic description of additional three fetuses and genotype-phenotype correlation.

Inversion duplication and terminal deletion of the long arm of chromosome 13 (inv dup del 13q) is a rare chromosomal rearrangement: only five patients have been reported, mostly involving a ring chromosome 13. We report on additional three fetuses with pure inv dup del 13q: Patient 1 had macrosomia, enlarged kidneys, hypersegmented lungs, unilateral moderate ventriculomegaly, and a mild form of hand and feet preaxial polydactyly; Patient 2 had intrauterine growth retardation, widely spaced eyes, left microphthalmia, right anophthalmia, short nose, bilateral absent thumbs, cutaneous syndactyly of toes 4 and 5, bifid third metacarpal, a small left kidney, hyposegmented lungs, and partial agenesis of the corpus callosum; Patient 3 had widely spaced eyes, long and smooth philtrum, low-set ears, median notch in the upper alveolar ridge, bifid tongue, cutaneous syndactyly of toes 2 and 3, enlarged kidneys and pancreas, arhinencephaly, and partial agenesis of the corpus callosum. We compared the phenotypes of these patients to those previously reported for ring chromosome 13, pure 13q deletions and duplications. We narrowed some critical regions previously reported for lung, kidney and fetal growth, and for thumb, cerebral, and eye anomalies.

Cytomegalovirus-induced brain malformations in fetuses.

Neurologic morbidity associated with congenital cytomegalovirus (CMV) infection is a major public health concern. The pathogenesis of cerebral lesions remains unclear. We report the neuropathologic substrates, the immune response, and the cellular targets of CMV in 16 infected human fetal brains aged 23 to 28.5 gestational weeks. Nine cases were microcephalic, 10 had extensive cortical lesions, 8 had hippocampal abnormalities, and 5 cases showed infection of the olfactory bulb. The density of CMV-immunolabeled cells correlated with the presence of microcephaly and the extent of brain abnormalities. Innate and adaptive immune responses were present but did not react against all CMV-infected cells. Cytomegalovirus infected all cell types but showed higher tropism for stem cells/radial glial cells. The results indicate that 2 main factors influence the neuropathologic outcome at this stage: the density of CMV-positive cells and the tropism of CMV for stem/progenitor cells. This suggests that the large spectrum of CMV-induced brain abnormalities is caused not only by tissue destruction but also by the particular vulnerability of stem cells during early brain development. Florid infection of the hippocampus and the olfactory bulb may expose these patients to the risk of neurocognitive and sensorineural handicap even in cases of infection at late stages of gestation.

Pre- and postnatal phenotype of 6p25 deletions involving the FOXC1 gene.

FOXC1 deletion, duplication, and mutations are associated with Axenfeld-Rieger anomaly, and Dandy-Walker malformation spectrum. We describe the clinical history, physical findings, and available brain imaging studies in three fetuses, two children, and one adult with 6p25 deletions encompassing FOXC1. Various combinations of ocular and cerebellar malformations were found. In all three fetuses, necropsy including detailed microscopic assessments of the eyes and brains showed ocular anterior segment dysgenesis suggestive of Axenfeld-Rieger anomaly. Five 6p25 deletions were terminal, including two derived from inherited reciprocal translocations; the remaining 6p25 deletion was interstitial. The size and breakpoints of these deletions were characterized using comparative genomic hybridization arrays. All six deletions included FOXC1. Our data confirm that FOXC1 haploinsufficiency plays a major role in the phenotype of patients with 6p25 deletions. Histopathological features of Axenfeld-Rieger anomaly were clearly identifiable before the beginning of the third-trimester of gestation.

Inner ear lesions in congenital cytomegalovirus infection of human fetuses.

Congenital cytomegalovirus (CMV) infection is the leading cause of non-hereditary congenital sensorineural hearing loss (SNHL). The natural course and the pathophysiology of inner ear lesions during human fetal CMV infection have not yet been reported. Inner ear lesions were investigated in six CMV-infected fetuses aged 19-35 postconceptional weeks and correlated with central nervous system (CNS) lesions. All the fetuses had high viral loads in the amniotic fluid and severe visceral and CNS lesions visible by ultrasound. Diffuse lesions consisting of both cytomegalic cells containing inclusion bodies and inflammation were found within all studied structures including the inner ear, brain, other organs, and placenta, suggesting hematogenous dissemination. Cochlear infection was consistently present and predominated in the stria vascularis (5/6), whereas the supporting cells in the organ of Corti were less often involved (2/6). Vestibular infection, found in 4/6 cases, was florid; the non-sensory epithelia, including the dark cells, were extensively infected. The endolymphatic sac was infected in 1 of 3 cases. The severity of inner ear infection was correlated with the CNS lesions, confirming the neurotropism of CMV. This study documenting infection of the structures involved in endolymph secretion and potassium homeostasis in fetuses with high amniotic fluid viral loads suggests that potassium dysregulation in the endolymphatic compartment of the inner ear may lead to secondary degeneration of the sensory structures. In addition, the occurrence of SNHL depends on the intensity and duration of the viral infection and inflammation.

Fetopathologic examination for early termination of pregnancy: dogma or necessity?

OBJECTIVE: Our objective was assessment of fetopathological examination after termination of pregnancy (TOP) for fetal anomalies with normal karyotype <17 weeks of gestation. STUDY DESIGN: This was a multicenter retrospective study. Records of TOP for fetal anomalies with normal karyotype were analyzed. Primary outcomes were modifications of genetic counseling and management of next subsequent pregnancies. Medical TOPs were compared with surgical TOPs. RESULTS: In all, 59 pregnancies were included (30 aspirations, 29 inductions). Fetopathological examination modified genetic counseling for 22 patients: 62% for the medical induction group vs 13% in the vacuum aspiration group (P < .001). Management of subsequent pregnancies was modified in 17% in the medical induction group vs 3% in the aspiration group (P = .06). CONCLUSION: Fetopathological examination for early TOP with normal karyotype is relevant, especially when an intact fetus is examined. Thanks to it, genetic counseling is often modified, as is management of the next pregnancy. Medical procedures should be preferred to surgical procedures.

Aphallia, lung agenesis and multiple defects of blastogenesis.

We report the association of aphallia, with imperforate anus, bilateral renal dysplasia and complete right lung agenesis in a fetus born of non-consanguineous parents. No maternal diabetes was present. The multiple mesodermal anomalies present in this male fetus, with a severe form of Uro-Rectal-Septum Malformation Sequence associated with unilateral lung agenesis, and rib segmentation anomaly is consistent with an extended defect of blastogenesis, with apparent common timing of the malformations around the 5th to 7th weeks of gestation.

DYRK1A interacts with the REST/NRSF-SWI/SNF chromatin remodelling complex to deregulate gene clusters involved in the neuronal phenotypic traits of Down syndrome.

The molecular mechanisms that lead to the cognitive defects characteristic of Down syndrome (DS), the most frequent cause of mental retardation, have remained elusive. Here we use a transgenic DS mouse model (152F7 line) to show that DYRK1A gene dosage imbalance deregulates chromosomal clusters of genes located near neuron-restrictive silencer factor (REST/NRSF) binding sites. We found that Dyrk1a binds the SWI/SNF complex known to interact with REST/NRSF. The mutation of a REST/NRSF binding site in the promoter of the REST/NRSF target gene L1cam modifies the transcriptional effect of Dyrk1a-dosage imbalance on L1cam. Dyrk1a dosage imbalance perturbs Rest/Nrsf levels with decreased Rest/Nrsf expression in embryonic neurons and increased expression in adult neurons. Using transcriptome analysis of embryonic brain subregions of transgenic 152F7 mouse line, we identified a coordinated deregulation of multiple genes that are responsible for dendritic growth impairment present in DS. Similarly, Dyrk1a overexpression in primary mouse cortical neurons induced severe reduction of the dendritic growth and dendritic complexity. We propose that DYRK1A overexpression-related neuronal gene deregulation via disturbance of REST/NRSF levels, and the REST/NRSF-SWI/SNF chromatin remodelling complex, significantly contributes to the neural phenotypic changes that characterize DS.