Search

Deficient Anterior pituitary with common Variable Immune Deficiency (DAVID) syndrome results from NFKB2 heterozygous mutations, causing adrenocorticotropic hormone deficiency (ACTHD) and primary hypogammaglobulinemia. While NFKB signaling plays a crucial role in the immune system, its connection to endocrine symptoms is unclear. We established a human disease model to investigate the role of NFKB2 in pituitary development by creating pituitary organoids from CRISPR/Cas9-edited human induced pluripotent stem cells (hiPSCs). Introducing homozygous TBX19 K146R/K146R missense pathogenic variant in hiPSC, an allele found in congenital isolated ACTHD, led to a strong reduction of corticotrophs number in pituitary organoids. Then, we characterized the development of organoids harboring NFKB2 D865G/D865G mutations found in DAVID patients. NFKB2 D865G/D865G mutation acted at different levels of development with mutant organoids displaying changes in the expression of genes involved on pituitary progenitor generation ( HESX1 , PITX1 , LHX3 ), hypothalamic secreted factors ( BMP4, FGF8, FGF10 ), epithelial-to-mesenchymal transition, lineage precursors development ( TBX19 , POU1F1 ) and corticotrophs terminal differentiation ( PCSK1, POMC ), and showed drastic reduction in the number of corticotrophs. Our results provide strong evidence for the direct role of NFKB2 mutations in the endocrine phenotype observed in patients leading to a new classification of a NFKB2 variant of previously unknown clinical significance as pathogenic in pituitary development., Competing Interests: TM, TF, NJ, PR, HE, AB, FC, TB No competing interests declared, (© 2023, Mac et al.)

Background: Congenital melanocytic naevi (CMN) can have a great impact on patients' lives owing to perceived stigmatization, and the risk of melanoma development and neurological complications. Development of a core outcome set (COS) for care and research in CMN will allow standard reporting of outcomes. This will enable comparison of outcomes, allowing professionals to offer advice about the best management options. In previous research, stakeholders (patients, parents and professionals) reached consensus on the core domains of the COS. To select the appropriate measurement instruments, the domains should be specified by outcomes., Objectives: To reach consensus on the specific core outcomes describing the core domains pertaining to clinical care and research in CMN., Methods: A list of provisional outcomes (obtained earlier) was critically reviewed by the Outcomes for COngenital MElanocytic Naevi (OCOMEN) research team and by relevant stakeholders through an online questionnaire, to refine this list and provide clear definitions for every outcome. When needed, discussion with individual participants was undertaken over the telephone or by email. During an online consensus meeting, stakeholders discussed the inclusion of potential outcomes. After the meeting, participants voted in two rounds for the inclusion of outcomes., Results: Forty-four stakeholders from 19 countries participated. Nine core outcomes were included in the COS relative to clinical care and 10 core outcomes for research., Conclusions: These core outcomes will enable standard reporting in future care and research of CMN. This study facilitates the next step of COS development: selecting the appropriate measurement instruments for every outcome., (© 2021 The Authors. British Journal of Dermatology published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists.)

Background: Medium, large and giant congenital melanocytic naevi (CMN) can impose a psychosocial burden on patients and families, and are associated with increased risk of developing melanoma or neurological symptoms. Lack of consensus on what outcomes to measure makes it difficult to advise patients and families about treatment and to set up best practice for CMN., Objectives: Fostering consensus among patient representatives and professionals, we aim to develop a core outcome set, defined as the minimum set of outcomes to measure and report in care and all clinical trials of a specific health condition. We focused on the 'what to measure' aspect, the so-called core domain set (CDS), following the COMET and CS-COUSIN guidelines., Methods: We conducted a systematic review to identify outcomes reported in the literature. Focus groups with patient representatives identified patient-reported outcomes. All these outcomes were classified into domains. Through e-Delphi surveys, 144 stakeholders from 27 countries iteratively rated the importance of domains and outcomes. An online consensus meeting attended by seven patient representatives and seven professionals finalized the CDS., Results: We reached consensus on six domains, four of which were applied to both care and research: 'quality of life', 'neoplasms', 'nervous system' and 'anatomy of skin'. 'Adverse events' was specific to care and 'pathology' to research., Conclusions: We have developed a CDS for medium-to-giant CMN. Its application in reporting care and research of CMN will facilitate treatment comparisons. The next step will be to reach consensus on the specific outcomes for each of the domains and what instruments should be used to measure these domains and outcomes., (© 2020 British Association of Dermatologists.)

We report a series of 6 melanocytic proliferations harboring both NRAS and IDH1 hotspot mutations. Clinically, there was no specific sex-ratio, ages ranged from 18 to 85 years, and the trunk and limbs were the most affected localizations. In half of the cases, progressive modification of a pre-existing nevus was reported. Morphologically, all tumors were predominantly based in the dermis and the most striking pathologic finding was the presence of a background architecture of congenital-type nevi with a superimposed biphasic pattern formed by dendritic pigmented melanocytes surrounding areas of nevoid melanocytes. This finding was further underscored by HMB45 staining, which was positive in the dendritic cells and negative in the nevoid melanocytes. Four cases displayed increased cellularity and 1 case showed increased dermal mitotic activity. DNA and RNA sequencing revealed NRAS and IDH1 comutations in all 6 cases, with homogenous expression data according to unsupervised clustering analysis. Array-comparative genomic hybridization revealed no copy number alteration for the 2 most cellular and mitogenic cases. All were surgically excised, available follow-up for 2 patients showed no relapse nor metastases. We hypothesize that the IDH1 mutation is a secondary event in a pre-existing NRAS-mutated nevus and could be in part responsible for the emergence of a pigmented dendritic dermal component. So far, such comutations have been reported in one benign melanocytic nevus and several melanomas. This combination could represent a new subgroup of intermediate prognosis (melanocytoma) with a distinctive morphology. Further acquisition of genomic anomalies could progressively lead to malignant transformation.

A new consensus-based classification of congenital melanocytic nevi (CMN) has recently been proposed. It includes categories for projected adult size (PAS) and location, satellite nevi counts, and morphologic characteristics (color heterogeneity, rugosity, nodularity, and hypertrichosis). The objective of the current study was to test the applicability of the new categorization scheme and to correlate classification outcome with the patient's history of melanoma and neurocutaneous melanocytosis (NCM). Children and adults with CMN attending a patient conference in Dallas, Texas, in 2012 were invited to participate in the study. Anamnestical data were collected using a standardized questionnaire. Two dermatologists performed clinical examinations. Of 45 patients enrolled, 33 had a giant CMN (G1 [>40 cm PAS], n = 13; G2 [>60 cm PAS], n = 20), 12 had an NCM (5 symptomatic, 7 asymptomatic), and 1 had a history of melanoma. CMN size was positively correlated with NCM (p < 0.05). The classification system allowed an easy and detailed phenotypic characterization of each individual CMN. CMN size and morphology were difficult to assess in patients after surgical removal, and the number of satellite nevi at birth or during infancy was not always known. Our report provides practical aids for the application of the newly proposed CMN classification. Prospective evaluation of accurately classified patients in CMN registries will reveal the predictive value of the scheme. The small study sample limits meaningful conclusions regarding the correlation between CMN parameters and the risk of NCM and melanoma., (© 2014 Wiley Periodicals, Inc.)

A highly enriched population of neural crest cells (NCCs) from amniote embryos, such as from chicks, mice and humans, is desirable for experiments in fate determination. NCCs are also useful for testing the functional effects of molecular changes underlying numerous human diseases of neural crest derivatives and for investigating their potential for therapeutic compensation. This protocol details embryonic microdissection followed by neural tube explantation. Conditions favoring NCC expansion and the maintenance of their stem cell-like properties are described. Although neural crest-like cells can be derived from a number of sites in the mature organism, full potential is best ensured by their purification from their source tissue at the outset of migration. Going from embryo to established cell line takes 4 d; the first is the most labor-intensive day, but minimal intervention is required thereafter.

Purpose: To decipher the biological pathways involved in keratoconus pathophysiology by determining the patterns of differential gene expression between keratoconus and control corneas., Methods: RNA was extracted from surgically removed corneas of 10 keratoconus patients and from normal corneas of 10 control patients who had undergone enucleation of an eye for ocular melanoma. Several hundred thousand RNA transcripts were assessed using exon microarrays. Statistical comparison and identification of differentially regulated and differentially spliced RNA transcripts was performed by comparing keratoconus cases and controls. In addition, relevant biological pathways were identified by information extraction using network biology., Results: Eighty-seven genes showed significant differences in expression levels. Among these, 69 were downregulated in keratoconus patients, particularly partners of the transcription factor AP-1. The 18 overexpressed genes include mucins, keratins, and genes involved in fibroblast proliferation. In addition, 36 genes were shown to be differentially spliced, including 9 among those that were differentially expressed. Network biology and analysis using Gene Ontology descriptors suggest that many members of both groups belong to pathways of apoptosis and regulation of the balance between cellular differentiation and proliferation., Conclusions: This work constitutes the first genome-wide transcriptome analysis of keratoconus patient corneas that include all currently known genes and exons. Differential expression suggests that mechanisms of cell loss resulting from antiproliferative and hyperapoptotic phenotypes may be responsible for the pathogenesis of keratoconus. Array information, experimental design, raw intensities, and processed log(2) ratios were deposited at the European Bioinformatic Institute's ArrayExpress database (http://www.ebi.ac.uk/arrayexpress/). The accession number is E-MEXP-2777.

Feingold syndrome (FS) is a syndromic microcephaly entity for which MYCN is the major disease-causing gene. We studied the expression pattern of MYCN at different stages of human embryonic development and collected a series of 17 FS and 12 isolated oesophageal atresia (IOA) cases. An MYCN gene deletion/mutation was identified in 47% of FS cases exclusively. We hypothesized that mutations or deletions of highly conserved non-coding elements (HCNEs) at the MYCN locus could lead to its misregulation and thereby to FS and/or IOA. We subsequently sequenced five HCNEs at the MYCN locus and designed a high-density tiling path comparative genomic hybridization array of 3.3 Mb at the MYCN locus. We found no mutations or deletions in this region, supporting the hypothesis of genetic heterogeneity in FS.

Neuroblastoma (NB) is a frequent embryonal tumor of sympathetic ganglia and adrenals with extremely variable outcome. Recently, somatic amplification and gain-of-function mutations of the anaplastic lymphoma receptor tyrosine kinase (ALK) gene, either somatic or germline, were identified in a significant proportion of NB cases. Here we report a novel syndromic presentation associating congenital NB with severe encephalopathy and abnormal shape of the brainstem on brain MRI in two unrelated sporadic cases harboring de novo, germline, heterozygous ALK gene mutations. Both mutations are gain-of-function mutations that have been reported in NB and NB cell lines. These observations further illustrate the role of oncogenes in both tumour predisposition and normal development, and shed light on the pleiotropic and activity-dependent role of ALK in humans. More generally, missing germline mutations relative to the spectrum of somatic mutations reported for a given oncogene may be a reflection of severe effects during embryonic development, and may prompt mutation screening in patients with extreme phenotypes., (© 2011 Wiley-Liss, Inc.)

Rare lethal disease gene identification remains a challenging issue, but it is amenable to new techniques in high-throughput sequencing (HTS). Cerebral proliferative glomeruloid vasculopathy (PGV), or Fowler syndrome, is a severe autosomal recessive disorder of brain angiogenesis, resulting in abnormally thickened and aberrant perforating vessels leading to hydranencephaly. In three multiplex consanguineous families, genome-wide SNP analysis identified a locus of 14 Mb on chromosome 14. In addition, 280 consecutive SNPs were identical in two Turkish families unknown to be related, suggesting a founder mutation reducing the interval to 4.1 Mb. To identify the causative gene, we then specifically enriched for this region with sequence capture and performed HTS in a proband of seven families. Due to technical constraints related to the disease, the average coverage was only 7×. Nonetheless, iterative bioinformatic analyses of the sequence data identified mutations and a large deletion in the FLVCR2 gene, encoding a 12 transmembrane domain-containing putative transporter. A striking absence of alpha-smooth muscle actin immunostaining in abnormal vessels in fetal PGV brains, suggests a deficit in pericytes, cells essential for capillary stabilization and remodeling during brain angiogenesis. This is the first lethal disease-causing gene to be identified by comprehensive HTS of an entire linkage interval., (Hum Mutat 31:1134-1141, 2010. © 2010 Wiley-Liss, Inc.)

Purpose: Anterior segment ocular dysgenesis (ASOD) is a broad heterogeneous group of diseases detectable at the clinical and molecular level. In a patient with bilateral congenital ASOD including aniridia and aphakia, a complex chromosomal rearrangement, inv(2)(p22.3q12.1)t(2;16)(q12.1;q12.2), was characterized at the molecular level, to identify candidate genes implicated in ASOD., Methods: After negative sequencing of the PAX6, FOXC1, and PITX2 genes, we used fluorescence in situ hybridization (FISH) and Southern blot analysis to characterize the chromosomal breakpoints. Candidate genes were selected, and in situ tissue expression analysis was performed on human fetuses and embryos., Results: Molecular analyses showed that the 16q12.2 breakpoint in this rearrangement occurs in a 625-bp region centromeric to the IRX3 gene, which belongs to the IRXB cluster. In situ hybridization expression studies showed that during early human embryonic development, the IRX3 gene is expressed in the anterior segment of the eye. Of interest, it has been shown previously that a highly conserved noncoding region (HCNCR) is located 300 kb centromeric to the IRX3 gene and induces, in a murine transgenic assay, an expression pattern fitting that of the IRX3 gene., Conclusions: The authors propose that the 16q12.2 breakpoint of this complex translocation is causally related to the ocular anterior segment dysgenesis observed in this patient. This translocation is assumed to separate the HCNCR from the IRXB cluster genes, thus deregulating the IRXB cluster and leading to the ASOD observed by a positional effect.

Cerebral proliferative glomeruloid vasculopathy (PGV) is a severe disorder of brain angiogenesis, resulting in abnormally thickened and aberrant perforating vessels, forming glomeruloids with inclusion-bearing endothelial cells. This peculiar vascular malformation was delineated by Fowler in 1972 as a stereotyped lethal fetal phenotype associating hydranencephaly-hydrocephaly with limb deformities, called Fowler syndrome (FS) or "proliferative vasculopathy and hydranencephaly-hydrocephaly" or "encephaloclastic proliferative vasculopathy" (OMIM#225790). In PGV, the disruptive impact of vascular malformation on the developing central nervous system (CNS) is now well admitted. However, molecular mechanisms of abnormal angiogenesis involving the CNS vasculature exclusively remain unknown, as no genes have been localized nor identified to date. We observed the pathognomonic FS vascular malformation in 16 fetuses, born to eight families, four consanguineous and four non-consanguineous. A diffuse form of PGV affecting the entire CNS and resulting in classical FS in 14 cases, can be contrasted to two cases with focal forms, confined to restricted territories of the CNS. Interestingly in PGV, immunohistological response to a marker of pericytes (SMA, Smooth in PGV Muscle Actin), was drastically reduced as compared to a match control. Our studies has expanded the description of FS to additional phenotypes, that could be called Fowler-like syndromes and suggest that the pathogenesis of PGV may be related to abnormal pericyte-dependent remodelling of the CNS vasculature, during CNS angiogenesis. Gene identification will determine the molecular basis of PGV and will help to know whether the Fowler-like phenotypes are due to the same underlying molecular mechanisms.

Pitt-Hopkins syndrome is a severe congenital encephalopathy recently ascribed to de novo heterozygous TCF4 gene mutations. We report a series of 13 novel PHS cases with a TCF4 mutation and show that EEG, brain magnetic resonance imagain (MRI), and immunological investigations provide valuable additional clues to the diagnosis. We confirm a mutational hot spot in the basic domain of the E-protein. Functional studies illustrate that heterodimerisation of mutant TCF4 proteins with a tissue-specific transcription factor is less effective than that homodimerisation in a luciferase reporter assay. We also show that the TCF4 expression pattern in human embryonic development is widespread but not ubiquitous. In summary, we further delineate an underdiagnosed mental retardation syndrome, highlighting TCF4 function during development and facilitating diagnosis within the first year of life., ((c) 2009 Wiley-Liss, Inc.)

Neuroblastoma (NB), an embryonic tumour originating from neural crest cells, is one of the most common solid tumours in childhood. Although NB is characterised by numerous recurrent, large-scale chromosome rearrangements, the genes targeted by these imbalances have remained elusive. We recently identified the paired-like homeobox 2B (PHOX2B, MIM 603851) gene as disease-causing in dysautonomic disorders including Congenital Central Hypoventilation Syndrome (CCHS), Hirschsprung disease (HSCR) and NB in various combinations. Most patients with NB due to a germline heterozygous PHOX2B gene mutation are familial and/or syndromic. PHOX2B, at chromosome 4p12, does not lie in a commonly rearranged locus in NB. To evaluate the role of PHOX2B in sporadic, isolated NB, we analysed 13 NB cell lines and 45 tumours for expression, mutations of coding and promoter sequences, loss of heterozygosity (LOH), or aberrant hypermethylation of PHOX2B (13 cell lines and 18 tumours). We didn't identify any mutation but LOH in about 10% of the cases and aberrant CpG dinucleotide methylation of the 500 bp PHOX2B promoter region in 4/31 tumours and cell lines (12.9%). Altogether, both germinal and somatic anomalies at the PHOX2B locus are found in NB.

We describe two fetal cases of microphthalmia/anophthalmia, pulmonary agenesis, and diaphragmatic defect. This rare association is known as Matthew-Wood syndrome (MWS; MIM 601186) or by the acronym "PMD" (Pulmonary agenesis, Microphthalmia, Diaphragmatic defect). Fewer than ten pre- and perinatal diagnoses of Matthew-Wood syndrome have been described to date. The cause is unknown, and the mode of transmission remains unclear. Most cases have been reported as isolated and sporadic, although recurrence among sibs has been observed once. Our two cases both occurred in consanguineous families, further supporting autosomal recessive transmission. In addition, in one family at least one of the elder sibs presented an evocatively similar phenotype. The spatiotemporal expression pattern of the FGF10 and FGFR2 genes in human embryos and the reported phenotypes of knockout mice for these genes spurred us to examine their coding sequences in our two cases of MWS. While in our patients, no causative sequence variations were identified in FGF10 or FGFR2, this cognate ligand-receptor pair and its downstream effectors remain functional candidates for MWS and similar associations of congenital ocular, diaphragmatic and pulmonary malformations., ((c) 2007 Wiley-Liss, Inc.)

One of the earliest priorities of the embryonic vascular system is to ensure the metabolic needs of the head. This review covers some of the principles that govern the cellular assembly and localization of blood vessels in the head. In order to understand the development and organization of the cephalic vascular tree, one needs to recall the morphogenetic movements underlying vertebrate head formation and giving rise to the constituent cells of the vascular system. Some of the major signaling molecules involved in vascular development are discussed, including the angiopoietins, the endothelins, the FGFs, the Notch receptors, the PDGFs, Sonic hedgehog, the TGF family and the VEGFs, in order to underline similarities between embryonic and postnatal vascular development, even in the context of increasingly divergent form.

Craniofacial abnormalities are one of the most common birth defects in humans, but little is known about the human genes that control these important developmental processes. To identify relevant genes, we analyzed transcription profiles of human pharyngeal arch 1 (PA1), a conserved embryonic structure that develops into the palate and jaw. Using microdissected, normal human craniofacial structures, we constructed 12 SAGE (serial analysis of gene expression) libraries and sequenced 606 532 tags. We also performed Affymetrix microarray analysis on 25 craniofacial targets. Our data revealed not only genes "enriched" or differentially expressed in PA1 during fourth and fifth week of human development, but also 6927 genes newly identified to be expressed in human PA1. Many of these genes are involved in biosynthetic processes and have binding function and catalytic activity. We compared expression profiles of human genes with those of mouse homologs to look for genes more specific to human craniofacial development and found 766 genes expressed in human PA1, but not in mouse PA1. We also identified 1408 genes that were expressed in mouse as well as human PA1 and could be useful in creating mouse models for human conditions. We confirmed conservation of some human PA1 expression patterns in mouse embryonic samples with whole mount in situ hybridization and real-time RT-PCR. This comprehensive approach to expression profiling gives insights into the early development of the craniofacial region and provides markers for developmental structures and candidate genes, including SET and CCT3, for diseases such as orofacial clefting and micrognathia.

Bardet-Biedl syndrome (BBS) is a multisystemic disorder characterized by postaxial polydactyly, progressive retinal dystrophy, obesity, hypogonadism, renal dysfunction, and learning difficulty. Other manifestations include diabetes mellitus, heart disease, hepatic fibrosis, and neurological features. The condition is genetically heterogeneous, and eight genes (BBS1-BBS8) have been identified to date. A mutation of the BBS1 gene on chromosome 11q13 is observed in 30%-40% of BBS cases. In addition, a complex triallelic inheritance has been established in this disorder--that is, in some families, three mutations at two BBS loci are necessary for the disease to be expressed. The clinical features of BBS that can be observed at birth are polydactyly, kidney anomaly, hepatic fibrosis, and genital and heart malformations. Interestingly, polydactyly, cystic kidneys, and liver anomalies (hepatic fibrosis with bile-duct proliferation) are also observed in Meckel syndrome, along with occipital encephalocele. Therefore, we decided to sequence the eight BBS genes in a series of 13 antenatal cases presenting with cystic kidneys and polydactyly and/or hepatic fibrosis but no encephalocele. These fetuses were mostly diagnosed as having Meckel or "Meckel-like" syndrome. In six cases, we identified a recessive mutation in a BBS gene (three in BBS2, two in BBS4, and one in BBS6). We found a heterozygous BBS6 mutation in three additional cases. No BBS1, BBS3, BBS5, BBS7, or BBS8 mutations were identified in our series. These results suggest that the antenatal presentation of BBS may mimic Meckel syndrome.

Thyroid dysgenesis (TD) is responsible for most cases of congenital hypothyroidism, a condition that affects about one in 4000 newborns. Mutations in PAX8, TITF1, or FOXE1 may account for congenital hypothyroidism in patients with either isolated TD or TD with associated malformations involving kidney, lung, forebrain, and palate. Pax8, titf1, and foxe1 are expressed in the mouse thyroid bud as soon as it differentiates on the pharyngeal floor. Because the spatio-temporal expression of these genes is unknown in humans, we decided to study them at different stages of human embryonic and fetal development. PAX8 and TITF1 were first expressed in the median thyroid primordium. Interestingly, PAX8 was also expressed in the thyroglossal duct and the ultimobranchial bodies. Human FOXE1 expression was detected later than in the mouse. PAX8 was also expressed in the developing central nervous system and kidney, including the ureteric bud and the main collecting ducts. TITF1 was expressed in the ventral forebrain and lung. FOXE1 expression was detected in the oropharyngeal epithelium and thymus. In conclusion, the expression patterns described here show some differences from those reported in the mouse. They explain the malformations associated with TD in patients carrying PAX8, TITF1, and FOXE1 gene mutations.

Congenital central hypoventilation syndrome (CCHS or Ondine's curse; OMIM 209880) is a life-threatening disorder involving an impaired ventilatory response to hypercarbia and hypoxemia. This core phenotype is associated with lower-penetrance anomalies of the autonomic nervous system (ANS) including Hirschsprung disease and tumors of neural-crest derivatives such as ganglioneuromas and neuroblastomas. In mice, the development of ANS reflex circuits is dependent on the paired-like homeobox gene Phox2b. Thus, we regarded its human ortholog, PHOX2B, as a candidate gene in CCHS. We found heterozygous de novo mutations in PHOX2B in 18 of 29 individuals with CCHS. Most mutations consisted of 5-9 alanine expansions within a 20-residue polyalanine tract probably resulting from non-homologous recombination. We show that PHOX2B is expressed in both the central and the peripheral ANS during human embryonic development. Our data support an essential role of PHOX2B in the normal patterning of the autonomous ventilation system and, more generally, of the ANS in humans.