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.
Cobblestone lissencephaly is a peculiar brain malformation with characteristic radiological anomalies. It is defined as cortical dysplasia that results when neuroglial overmigration into the ...arachnoid space forms an extracortical layer that produces agyria and/or a “cobblestone” brain surface and ventricular enlargement. Cobblestone lissencephaly is pathognomonic of a continuum of autosomal-recessive diseases characterized by cerebral, ocular, and muscular deficits. These include Walker-Warburg syndrome, muscle-eye-brain disease, and Fukuyama muscular dystrophy. Mutations in POMT1, POMT2, POMGNT1, LARGE, FKTN, and FKRP identified these diseases as alpha-dystroglycanopathies. Our exhaustive screening of these six genes, in a cohort of 90 fetal cases, led to the identification of a mutation in only 53% of the families, suggesting that other genes might also be involved. We therefore decided to perform a genome-wide study in two multiplex families. This allowed us to identify two additional genes: TMEM5 and ISPD. Because TMEM has a glycosyltransferase domain and ISPD has an isoprenoid synthase domain characteristic of nucleotide diP-sugar transferases, these two proteins are thought to be involved in the glycosylation of dystroglycan. Further screening of 40 families with cobblestone lissencephaly identified nonsense and frameshift mutations in another four unrelated cases for each gene, increasing the mutational rate to 64% in our cohort. All these cases displayed a severe phenotype of cobblestone lissencephaly A. TMEM5 mutations were frequently associated with gonadal dysgenesis and neural tube defects, and ISPD mutations were frequently associated with brain vascular anomalies.
L1 syndrome results from mutations in the
L1CAM
gene located at Xq28. It encompasses a wide spectrum of diseases, X-linked hydrocephalus being the most severe phenotype detected in utero, and whose ...pathophysiology is incompletely understood. The aim of this study was to report detailed neuropathological data from patients with mutations, to delineate the neuropathological criteria required for
L1CAM
gene screening in foetuses by characterizing the sensitivity, specificity and positive predictive value of the cardinal signs, and to discuss the main differential diagnoses in non-mutated foetuses in order to delineate closely related conditions without
L1CAM
mutations. Neuropathological data from 138 cases referred to our genetic laboratory for screening of the
L1CAM
gene were retrospectively reviewed. Fifty-seven cases had deleterious
L1CAM
mutations. Of these, 100 % had hydrocephalus, 88 % adducted thumbs, 98 % pyramidal tract agenesis/hypoplasia, 90 % stenosis of the aqueduct of Sylvius and 68 % agenesis/hypoplasia of the corpus callosum. Two foetuses had
L1CAM
mutations of unknown significance. Seventy-nine cases had no
L1CAM
mutations; these were subdivided into four groups: (1) hydrocephalus sometimes associated with corpus callosum agenesis (44 %); (2) atresia/forking of the aqueduct of Sylvius/rhombencephalosynapsis spectrum (27 %); (3) syndromic hydrocephalus (9 %), and (4) phenocopies with no mutations in the
L1CAM
gene (20 %) and in whom family history strongly suggested an autosomal recessive mode of transmission. These data underline the existence of closely related clinical entities whose molecular bases are currently unknown. The identification of the causative genes would greatly improve our knowledge of the defective pathways involved in these cerebral malformations.
Objective To investigate the association between histologic chorioamnionitis (HCA) and bronchopulmonary dysplasia (BPD) in very preterm infants, both in a general population and for those born after ...spontaneous preterm labor and after preterm premature rupture of membranes (pPROM). Study design This study included 2513 live born singletons delivered at 24-31 weeks of gestation from a national prospective population-based cohort of preterm births; 1731 placenta reports were available. HCA was defined as neutrophil infiltrates in the amnion, chorion of the membranes, or chorionic plate, associated or not with funisitis. The main outcome measure was moderate or severe BPD. Analyses involved logistic regressions and multiple imputation for missing data. Results The incidence of HCA was 28.4% overall: 38% in cases of preterm labor, 64% in cases of pPROM, and less than 5% in cases of vascular disorders. Overall, the risk of BPD after adjustment for gestational age, sex, and antenatal steroids was reduced for infants with HCA (HCA alone: aOR 0.6 95% CI 0.4-0.9; associated with funisitis: aOR 0.5 95% CI 0.3-0.8). This finding was explained by the high rate of BPD and low rate of chorioamnionitis among children with fetal growth restriction. HCA was not associated with BPD in the preterm labor (13.4% vs 8.5%; aOR 0.9; 95% CI 0.5-1.8) or in the pPROM group (12.9% vs 12.1%; aOR 0.6; 95% CI 0.3-1.3). Conclusion In homogeneous groups of infants born after preterm labor or pPROM, HCA is not associated with BPD.
Oral-facial-digital syndrome type VI (OFD VI) is a recessive ciliopathy defined by two diagnostic criteria: molar tooth sign (MTS) and one or more of the following: (1) tongue hamartoma (s) and/or ...additional frenula and/or upper lip notch; (2) mesoaxial polydactyly of one or more hands or feet; (3) hypothalamic hamartoma. Because of the MTS, OFD VI belongs to the “Joubert syndrome related disorders”. Its genetic aetiology remains largely unknown although mutations in the
TMEM216
gene, responsible for Joubert (JBS2) and Meckel-Gruber (MKS2) syndromes, have been reported in two OFD VI patients. To explore the molecular cause(s) of OFD VI syndrome, we used an exome sequencing strategy in six unrelated families followed by Sanger sequencing. We identified a total of 14 novel mutations in the
C5orf42
gene in 9/11 families with positive OFD VI diagnostic criteria including a severe fetal case with microphthalmia, cerebellar hypoplasia, corpus callosum agenesis, polydactyly and skeletal dysplasia.
C5orf42
mutations have already been reported in Joubert syndrome confirming that OFD VI and JBS are allelic disorders, thus enhancing our knowledge of the complex, highly heterogeneous nature of ciliopathies.
Objective
To study the histoanatomical structure of laryngeal atresia with a focus on the laryngeal functional components in order to evaluate the functional prognosis of laryngeal atresia repair.
...Methods
Twenty‐one consecutives cases of laryngeal atresia were diagnosed at our institution between 2009 and 2016. Morphological analysis by macroscopic exam during autopsy was performed in 19 cases. Histological study of the larynx included hematoxylin and eosin staining and protein S100 immunostaining. Our analysis focused on the vocal folds, structures of the lamina propria, cricoarytenoid joints, muscles, and innervation. For each case, associated malformations were classified into two groups: severe and moderate.
Results
Antenatal diagnosis was suspected because of congenital high airway obstruction syndrome in nine cases (37%).
Associated malformations were present in 19 cases (90%), including severe malformations in 12 cases (57%). Atresia involved the cricoid in all cases, with a residual lumen in only one case and the glottis in 18 cases. Separation between the cricoid and arytenoid cartilages was observed in all cases. Fusion of the vocal process of the arytenoids in the midline was present in 13 cases.
According to the gestational age, posterior maculae flavae (MF) were present in 17 of 19 cases, with abnormal structure and median fusion in 13 cases. Anterior MF were present in nine of 18 cases, with fusion on the midline in five cases.
Intrinsic abductors and adductors muscles were identifiable in all cases, with fusion of thyroarytenoids muscles in the midline in 18 cases. Both recurrent laryngeal nerves were observed in all cases.
Conclusion
Laryngeal atresia is generally associated with other malformations, with a high risk of fatal outcomes. We observed that the functional structures of the glottic plane were present in most cases, with the exception of MF, which were frequently abnormal.
Level of Evidence
4 Laryngoscope, 130:252–256, 2020
Aims
SALL4 is a marker of germ cell tumours. The aim of this study was to investigate SALL4 expression in blastemal tumours, particularly in hepatoblastoma.
Methods and results
The study included 12 ...hepatoblastomas. Eight hepatoblastomas were pure epithelial tumours, and four were mixed epithelial and mesenchymal tumours. The patients were nine males and three females with a mean age of 14.6 months. Immunohistochemistry was performed with an antibody against SALL4, using an automated immunostainer. Seven of 12 hepatoblastomas showed nuclear staining only in the embryonal component. Fetal and mesenchymal components were negative.
Conclusions
SALL4 is expressed in blastemal tumours, particularly in the embryonal subtype of hepatoblastoma. Pathologists need to be aware of such expression so that misdiagnosis can be avoided.
Background
Osteogenesis imperfecta (OI), commonly called “brittle bone disease”, is a genetic disorder characterised by increased bone fragility and decreased bone density due to quantitative and/or ...qualitative abnormalities of type I collagen. Different types of OI exist, from mild to severe; they may lead to death, multiple bone fractures, skeletal deformity and short stature.
Methods
Severe cases are usually diagnosed before birth and may incite the parents to choose therapeutic abortion, whereas milder cases are much more difficult to diagnose and may be sometimes confused with non-accidental injury (NAI) (“child abuse”) in young children. Whatever the degree of severity, conventional radiography still remains the mainstay in diagnosing OI.
Results
The prognosis of this disorder has changed in the last few years thanks to biphosphonate therapy.
Conclusion
The aim of this pictorial review is to illustrate the radiographic manifestations of OI, including in children receiving biphosphonates, and to outline specific patterns that help differentiate OI from NAI when necessary.
Key Points
•
The main radiographic features of OI are osteopenia, bone fractures and bone deformities.
•
Some radiographic features depend on the type of OI or may be encountered with biphosphonates.
The combination of pulmonary agenesis/dysgenesis/hypoplasia, microphthalmia/anophthalmia, and a diaphragmatic defect (agenesis or eventration) is a rare syndrome presumed to have an autosomal ...recessive mode of inheritance based on a report of affected siblings born to unaffected parents Seller et al., 1996. The condition is known as Spear syndrome and Matthew-Wood syndrome, although genetic heterogeneity cannot be ruled out. We report on eight patients with this condition including a living child, three sibs and three isolated cases. Most presented with fetal ultrasound findings of microphthalmia/anophthalmia, and diaphragmatic eventration/hernia and in five, cardiac abnormalities were also found. The earliest detection was at 20 weeks gestation. This is the second report of sibs affected with this condition, which supports an autosomal recessive mode of inheritance. We present the first and only reported living patient with this condition and expand the intrafamilial, interfamilial, and ethnic variability of this condition. We suggest changing the condition's name to PDAC to reflect the most important components of this condition.
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