Weill-Marchesani syndrome: natural history and genotype-phenotype correlations from 18 news cases and review of literature.

BACKGROUND: Weill-Marchesani syndrome (WMS) belongs to the group of acromelic dysplasias, defined by short stature, brachydactyly and joint limitations. WMS is characterised by specific ophthalmological abnormalities, although cardiovascular defects have also been reported. Monoallelic variations in FBN1 are associated with a dominant form of WMS, while biallelic variations in ADAMTS10, ADAMTS17 and LTBP2 are responsible for a recessive form of WMS. OBJECTIVE: Natural history description of WMS and genotype-phenotype correlation establishment. MATERIALS AND METHODS: Retrospective multicentre study and literature review. INCLUSION CRITERIA: clinical diagnosis of WMS with identified pathogenic variants. RESULTS: 61 patients were included: 18 individuals from our cohort and 43 patients from literature. 21 had variants in ADAMTS17, 19 in FBN1, 19 in ADAMTS10 and 2 in LTBP2. All individuals presented with eye anomalies, mainly spherophakia (42/61) and ectopia lentis (39/61). Short stature was present in 73% (from -2.2 to -5.5 SD), 10/61 individuals had valvulopathy. Regarding FBN1 variants, patients with a variant located in transforming growth factor (TGF)-ß-binding protein-like domain 5 (TB5) domain were significantly smaller than patients with FBN1 variant outside TB5 domain (p=0.0040). CONCLUSION: Apart from the ophthalmological findings, which are mandatory for the diagnosis, the phenotype of WMS seems to be more variable than initially described, partially explained by genotype-phenotype correlation.

Expanding the genetic and clinical spectrum of Tatton-Brown-Rahman syndrome in a series of 24 French patients.

BACKGROUND: Tatton-Brown-Rahman syndrome (TBRS; OMIM 615879), also known as DNA methyltransferase 3 alpha (DNMT3A)-overgrowth syndrome (DOS), was first described by Tatton-Brown in 2014. This syndrome is characterised by overgrowth, intellectual disability and distinctive facial features and is the consequence of germline loss-of-function variants in DNMT3A, which encodes a DNA methyltransferase involved in epigenetic regulation. Somatic variants of DNMT3A are frequently observed in haematological malignancies, including acute myeloid leukaemia (AML). To date, 100 individuals with TBRS with de novo germline variants have been described. We aimed to further characterise this disorder clinically and at the molecular level in a nationwide series of 24 French patients and to investigate the correlation between the severity of intellectual disability and the type of variant. METHODS: We collected genetic and medical information from 24 individuals with TBRS using a questionnaire released through the French National AnDDI-Rares Network. RESULTS: Here, we describe the first nationwide French cohort of 24 individuals with germline likely pathogenic/pathogenic variants in DNMT3A, including 17 novel variants. We confirmed that the main phenotypic features were intellectual disability (100% of individuals), distinctive facial features (96%) and overgrowth (87%). We highlighted novel clinical features, such as hypertrichosis, and further described the neurological features and EEG results. CONCLUSION: This study of a nationwide cohort of individuals with TBRS confirms previously published data and provides additional information and clarifies clinical features to facilitate diagnosis and improve care. This study adds value to the growing body of knowledge on TBRS and broadens its clinical and molecular spectrum.

First Case of Acute Myocarditis Caused by Metapneumovirus in an Immunocompromised 14-year-old Girl.

Background: Human metapneumovirus (hMPV) is a paramyxovirus, well known as a causative agent of respiratory tract infections. Non-respiratory manifestations, including cardiac impairments, remain rare. Only two cases of myocarditis caused by hMPV have been described in adults. Case description: We present the case of a 14-year-old female suffering from Burkitt leukemia and diagnosed with severe myocarditis caused by hMPV, based on results from real-time polymerase chain reaction (RT-PCR) and magnetic resonance imaging (MRI). She was successfully treated by venoarterial extracorporeal membrane oxygenation and intravenous immunoglobulins. She was discharged from pediatric intensive care unit (PICU) 3 weeks later. Conclusion: This is the first pediatric case of hMPV myocarditis requiring venoarterial extracorporeal membrane oxygenation. How to cite this article: Makhlouf A, Peipoch L, Duport P, Darrieux E, Reguerre Y, Ramful D, et al. First Case of Acute Myocarditis Caused by Metapneumovirus in an Immunocompromised 14-year-old Girl. Indian J Crit Care Med 2022;26(6):745-747.

Clinical and neuroimaging findings in 33 patients with MCAP syndrome: A survey to evaluate relevant endpoints for future clinical trials.

Megalencephaly-CApillary malformation-Polymicrogyria (MCAP) syndrome results from somatic mosaic gain-of-function variants in PIK3CA. Main features are macrocephaly, somatic overgrowth, cutaneous vascular malformations, connective tissue dysplasia, neurodevelopmental delay, and brain anomalies. The objectives of this study were to describe the clinical and radiological features of MCAP, to suggest relevant clinical endpoints applicable in future trials of targeted drug therapy. Based on a French collaboration, we collected clinical features of 33 patients (21 females, 12 males, median age of 9.9 years) with MCAP carrying mosaic PIK3CA pathogenic variants. MRI images were reviewed for 21 patients. The main clinical features reported were macrocephaly at birth (20/31), postnatal macrocephaly (31/32), body/facial asymmetry (21/33), cutaneous capillary malformations (naevus flammeus 28/33, cutis marmorata 17/33). Intellectual disability was present in 15 patients. Among the MRI images reviewed, the neuroimaging findings were megalencephaly (20/21), thickening of corpus callosum (16/21), Chiari malformation (12/21), ventriculomegaly/hydrocephaly (10/21), cerebral asymmetry (6/21) and polymicrogyria (2/21). This study confirms the main known clinical features that defines MCAP syndrome. Taking into account the phenotypic heterogeneity in MCAP patients, in the context of emerging clinical trials, we suggest that patients should be evaluated based on the main neurocognitive expression on each patient.

A new mutational hotspot in the SKI gene in the context of MFS/TAA molecular diagnosis.

SKI pathogenic variations are associated with Shprintzen-Goldberg Syndrome (SGS), a rare systemic connective tissue disorder characterized by craniofacial, skeletal and cardiovascular features. So far, the clinical description, including intellectual disability, has been relatively homogeneous, and the known pathogenic variations were located in two different hotspots of the SKI gene. In the course of diagnosing Marfan syndrome and related disorders, we identified nine sporadic probands (aged 2-47 years) carrying three different likely pathogenic or pathogenic variants in the SKI gene affecting the same amino acid (Thr180). Seven of these molecular events were confirmed de novo. All probands displayed a milder morphological phenotype with a marfanoid habitus that did not initially lead to a clinical diagnosis of SGS. Only three of them had learning disorders, and none had intellectual disability. Six out of nine presented thoracic aortic aneurysm, which led to preventive surgery in the oldest case. This report extends the phenotypic spectrum of variants identified in the SKI gene. We describe a new mutational hotspot associated with a marfanoid syndrome with no intellectual disability. Cardiovascular involvement was confirmed in a significant number of cases, highlighting the importance of accurately diagnosing SGS and ensuring appropriate medical treatment and follow-up.

High prevalence of Bardet-Biedl syndrome in La Réunion Island is due to a founder variant in ARL6/BBS3.

Bardet-Biedl syndrome (BBS) is a rare ciliopathy with variable retinal dystrophy, polydactyly, renal abnormalities, obesity, cognitive impairment, and hypogonadism. Biallelic pathogenic variants have been identified in 24 genes, leading to BBS in an autosomal recessive inheritance pattern. In this study, we investigated a cohort of 16 families (20 individuals) presenting with typical BBS originating from La Réunion Island using sequencing (Sanger and high-throughput methods) and SNP array. In eight families (12 individuals) we identified the same ARL6/BBS3 variation [c.535G > A, p.(Asp179Asn)]. Bioinformatics and functional analyses revealed an effect of this variant on the splicing of ARL6/BBS3. Owing to the relatively high frequency of this variant, a possible founder effect was suspected. Genotyping of six individuals revealed a common 3.8-Mb haplotype and estimated the most recent common ancestor to about eight generations confirmed by the known genealogy. Knowledge of this founder effect modifies our diagnostic strategy and enables a personalized genetic counseling for patients from La Réunion Island. Being the first description of BBS patients from La Réunion Island, we could estimate its prevalence between ~1/45000 and ~ 1/66000 individuals.

SETD2 related overgrowth syndrome: Presentation of four new patients and review of the literature.

The common genes responsible for overgrowth syndromes play key roles in regulating transcription through histone modification and chromatin modeling. The SETD2 gene encoding a H3K36 trimethyltransferase is implicated in Sotos-like syndrome. This syndrome is characterized by postnatal overgrowth, macrocephaly, obesity, speech delay, and advanced carpal ossification. We report four new patients with constitutional SETD2 mutations and review nine earlier reported patients. Almost all patients presented with macrocephaly associated with advanced stature and obesity in half of the cases. In addition to these principal manifestations, neurodevelopmental disorders are common such as intellectual disability (83%), autism spectrum disorders (89%), and behavioral difficulties (100%) with aggressive outbursts (83%). A variety of features such as joint hypermobility (29%), hirsutism (33%), and naevi (50%) were also reported. Constitutional SETD2 mutations are intragenic loss-of-function variants with truncating (69%) and missense (31%) mutations. Functional studies are necessary to improve understanding of the pathogenicity of some missense SETD2 mutations.

Epidemiology of achondroplasia: A population-based study in Europe.

Achondroplasia is a rare genetic disorder resulting in short-limb skeletal dysplasia. We present the largest European population-based epidemiological study to date using data provided by the European Surveillance of Congenital Anomalies (EUROCAT) network. All cases of achondroplasia notified to 28 EUROCAT registries (1991-2015) were included in the study. Prevalence, birth outcomes, prenatal diagnosis, associated anomalies, and the impact of paternal and maternal age on de novo achondroplasia were presented. The study population consisted of 434 achondroplasia cases with a prevalence of 3.72 per 100,000 births (95%CIs: 3.14-4.39). There were 350 live births, 82 terminations of pregnancy after prenatal diagnosis, and two fetal deaths. The prenatal detection rate was significantly higher in recent years (71% in 2011-2015 vs. 36% in 1991-1995). Major associated congenital anomalies were present in 10% of cases. About 20% of cases were familial. After adjusting for maternal age, fathers >34 years had a significantly higher risk of having infants with de novo achondroplasia than younger fathers. Prevalence was stable over time, but regional differences were observed. All pregnancy outcomes were included in the prevalence estimate with 80.6% being live born. The study confirmed the increased risk for older fathers of having infants with de novo achondroplasia.

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.

Mutation update for the GPC3 gene involved in Simpson-Golabi-Behmel syndrome and review of the literature.

Simpson-Golabi-Behmel syndrome (SGBS) is an X-linked multiple congenital anomalies and overgrowth syndrome caused by a defect in the glypican-3 gene (GPC3). Until now, GPC3 mutations have been reported in isolated cases or small series and the global genotypic spectrum of these mutations has never been delineated. In this study, we review the 57 previously described GPC3 mutations and significantly expand this mutational spectrum with the description of 29 novel mutations. Compiling our data and those of the literature, we provide an overview of 86 distinct GPC3 mutations identified in 120 unrelated families, ranging from single nucleotide variations to complex genomic rearrangements and dispersed throughout the entire coding region of GPC3. The vast majority of them are deletions or truncating mutations (frameshift, nonsense mutations) predicted to result in a loss-of-function. Missense mutations are rare and the two which were functionally characterized, impaired GPC3 function by preventing GPC3 cleavage and cell surface addressing respectively. This report by describing for the first time the wide mutational spectrum of GPC3 could help clinicians and geneticists in interpreting GPC3 variants identified incidentally by high-throughput sequencing technologies and also reinforces the need for functional validation of non-truncating mutations (missense, in frame mutations, duplications).

Specific variants in WDR35 cause a distinctive form of Ellis-van Creveld syndrome by disrupting the recruitment of the EvC complex and SMO into the cilium.

Most patients with Ellis-van Creveld syndrome (EvC) are identified with pathogenic changes in EVC or EVC2, however further genetic heterogeneity has been suggested. In this report we describe pathogenic splicing variants in WDR35, encoding retrograde intraflagellar transport protein 121 (IFT121), in three families with a clinical diagnosis of EvC but having a distinctive phenotype. To understand why WDR35 variants result in EvC, we analysed EVC, EVC2 and Smoothened (SMO) in IFT-A deficient cells. We found that the three proteins failed to localize to Wdr35(-/-) cilia, but not to the cilium of the IFT retrograde motor mutant Dync2h1(-/-), indicating that IFT121 is specifically required for their entry into the ciliary compartment. Furthermore expression of Wdr35 disease cDNAs in Wdr35(-/-) fibroblasts revealed that the newly identified variants lead to Hedgehog signalling defects resembling those of Evc(-/-) and Evc2(-/-) mutants. Together our data indicate that splicing variants in WDR35, and possibly in other IFT-A components, underlie a number of EvC cases by disrupting targeting of both the EvC complex and SMO to cilia.

Mutations of the Imprinted CDKN1C Gene as a Cause of the Overgrowth Beckwith-Wiedemann Syndrome: Clinical Spectrum and Functional Characterization.

Beckwith-Wiedemann syndrome (BWS) is an imprinting disorder associating macroglossia, abdominal wall defects, visceromegaly, and a high risk of childhood tumor. Molecular anomalies are mostly epigenetic; however, mutations of CDKN1C are implicated in 8% of cases, including both sporadic and familial forms. We aimed to describe the phenotype of BWS patients with CDKN1C mutations and develop a functional test for CDKN1C mutations. For each propositus, we sequenced the three exons and intron-exon boundaries of CDKN1C in patients presenting a BWS phenotype, including abdominal wall defects, without 11p15 methylation defects. We developed a functional test based on flow cytometry. We identified 37 mutations in 38 pedigrees (50 patients and seven fetuses). Analysis of parental samples when available showed that all mutations tested but one was inherited from the mother. The four missense mutations led to a less severe phenotype (lower frequency of exomphalos) than the other 33 mutations. The following four tumors occurred: one neuroblastoma, one ganglioneuroblastoma, one melanoma, and one acute lymphoid leukemia. Cases of BWS caused by CDKN1C mutations are not rare. CDKN1C sequencing should be performed for BWS patients presenting with abdominal wall defects or cleft palate without 11p15 methylation defects or body asymmetry, or in familial cases of BWS.

Delineation of EFTUD2 haploinsufficiency-related phenotypes through a series of 36 patients.

Mandibulofacial dysostosis, Guion-Almeida type (MFDGA) is a recently delineated multiple congenital anomalies/mental retardation syndrome characterized by the association of mandibulofacial dysostosis (MFD) with external ear malformations, hearing loss, cleft palate, choanal atresia, microcephaly, intellectual disability, oesophageal atresia (OA), congenital heart defects (CHDs), and radial ray defects. MFDGA emerges as a clinically recognizable entity, long underdiagnosed due to highly variable presentations. The main differential diagnoses are CHARGE and Feingold syndromes, oculoauriculovertebral spectrum, and other MFDs. EFTUD2, located on 17q21.31, encodes a component of the major spliceosome and is disease causing in MFDGA, due to heterozygous loss-of-function (LoF) mutations. Here, we describe a series of 36 cases of MFDGA, including 24 previously unreported cases, and we review the literature in order to delineate the clinical spectrum ascribed to EFTUD2 LoF. MFD, external ear anomalies, and intellectual deficiency occur at a higher frequency than microcephaly. We characterize the evolution of the facial gestalt at different ages and describe novel renal and cerebral malformations. The most frequent extracranial malformation in this series is OA, followed by CHDs and skeletal abnormalities. MFDGA is probably more frequent than other syndromic MFDs such as Nager or Miller syndromes. Although the wide spectrum of malformations complicates diagnosis, characteristic facial features provide a useful handle.

Fryns syndrome without diaphragmatic hernia, DOOR syndrome or Fryns-like syndrome? Report on patients from Indian Ocean islands.

We report on six patients (five unpublished patients) from the Indian Ocean islands, with coarse face, cleft lip or palate, eye anomalies, brachytelephalangy, nail hypoplasia, various malformations (genitourinary or cerebral), abnormal electroencephalograms with impaired neurological examination and lethal outcome. Massive polyhydramnios was noted in the third trimester of pregnancy and neonatal growth was normal or excessive. The combination of the features is consistent with the diagnosis of Fryns syndrome (FS) without congenital diaphragmatic hernia. Besides chromosomal aberrations and microdeletion syndrome, differential diagnoses include conditions overlapping with FS such as Simpson-Golabi-Behmel, and conditions with hypoplasia/absence of the distal phalanges such as DOOR syndrome, Schinzel-Giedion syndrome, and Rudiger syndrome.

Prenatal and neonatal phenotype of Larsen of La Réunion Island syndrome (B4GALT7-linkeropathy).

Larsen of La Réunion Island syndrome (LRS) is an autosomal recessive condition associated with multiple large joint dislocations, clubfeet, severe dwarfism, and distinctive facial features. LRS is caused by a recurrent homozygous variant in B4GALT7 gene with a founder effect in La Réunion population. Proteoglycans (PG) that are a major component of the extracellular matrix, are composed of a core protein connected to a glycosaminoglycans side chain via a tetrasaccharide linker region. B4GALT7 encodes galactosyltransferase I, one of the enzymes involved in the biosynthesis of the linker region. Conditions caused by pathogenic biallelic variants in genes implicated in the synthesis of the tetrasaccharide linker of PG are known as linkeropathies. Prenatal features are rarely described in this group of chondrodysplasias. We present a series of 12 unpublished patients having LRS and describe the perinatal phenotype. All the patients had a prenatal growth restriction with brevity of limbs. The other features revealed by ultrasounds were increased nuchal translucency at 10-12 weeks of gestation (50 %), feet abnormalities (clubfeet or metatarsus varus) (25 %), dislocation affecting at least one large joint (elbow, knee, wrist) (25 %). Bilateral bowing of femora was noted for two fetuses. Fibular hypertrophy was noted for one fetus. Prenatal helical computed tomography (CT) performed in three pregnancies showed additional data such as bowing of the forearm bones, proximal radio-ulnar synostosis, or dislocation of large joints. Prenatal sonographic and helical CT findings led to the prenatal diagnosis of LRS in four patients. We confirm that the neonatal clinical picture of LRS has an important overlap with that reported in patients with B4GALT7 deficiency outside La Réunion Island and other linkeropathies. The core of the phenotypic spectrum combines low birth height, micromelia, hypermobility, dislocation of at least one large joint, facial features with prominent eyes, microstomia, depressed nasal bridge, and midface hypoplasia. Other clinical features include clubfeet (33%), bifid thumb in one patient, and cardiac abnormalities in two patients. Radiological findings include radio-ulnar synostosis (75%), metaphyseal flaring, precocious carpal ossification, and a Swedish key appearance of the proximal femora. Finally, we also report radiological features rarely described in B4GALT7-linkeropathies, including bowing of the femora and fibular hypertrophy. Our results confirm the phenotypic continuum of LRS within linkeropathies with some additional findings, including a high frequency of clubfeet usually described in B3GALT6-linkeropathies, the presence of congenital heart diseases usually described in B3GAT3-linkeropathies, and a high frequency of metaphyseal flaring usually reported in B3GALT6 or XITLT1-linkeropathies. This is the first study that describes the perinatal phenotype in a cohort of patients with LRS. This study can help improve the prenatal diagnosis of the linkeropathies and add this group of conditions to the differential diagnosis of chondrodysplasias with multiple dislocations. In view of the founder effect for LRS in La Réunion Island, this disease should be suspected in fetuses with growth restriction and micromelia. Thus in case of LOH which include B4GALT7 identified in SNP-array, we recommend performing a targeted Sanger sequencing for the recurrent mutation c.808C > T; p. (Arg270Cys).

First Description of a Large Clinical Series of Fetal Alcohol Spectrum Disorders Children and Adolescents in Reunion Island, France.

BACKGROUND: Despite several diagnostic guidelines, Fetal Alcohol Spectrum Disorders (FASDs) remain underdiagnosed or misdiagnosed, delaying the care of these patients and support for families. OBJECTIVE: This study aims to help professionals caring for these children and their families to suspect this diagnosis earlier and to provide the most appropriate follow-up. METHODS: A retrospective chart review with monocentric recruitment was performed at the Genetics Unit of the University Hospital of Reunion Island. A total of 147 children and adolescents with FASDs were included. RESULTS: Prenatal alcohol exposure was associated with paternal alcohol consumption in 42.9%, and a high rate of prematurity (33.3%) was observed. Sixty percent of children or adolescents were placed in foster families. Learning difficulties without cognitive deficits were found in 65.8% of cases (50/76). Postural control and fine motor skills disabilities were described, respectively, in 54.7% (35/64) and 72.5% (50/69) of cases. A systematic genetic assessment was carried out, identifying in these FASD patients an associated Copy Number Variation (CNVs) in 22.6% of cases. CONCLUSION: Children with FASDs combine significant vulnerabilities, associating exposure to alcohol during the preconception and/or the prenatal period, prematurity, complex familial and sociocultural living conditions, and a genetic anomaly in almost a quarter of cases.

Lessons from two series by physicians and caregivers' self-reported data in DDX3X-related disorders.

INTRODUCTION AND METHODS: We report two series of individuals with DDX3X variations, one (48 individuals) from physicians and one (44 individuals) from caregivers. RESULTS: These two series include several symptoms in common, with fairly similar distribution, which suggests that caregivers' data are close to physicians' data. For example, both series identified early childhood symptoms that were not previously described: feeding difficulties, mean walking age, and age at first words. DISCUSSION: Each of the two datasets provides complementary knowledge. We confirmed that symptoms are similar to those in the literature and provides more details on feeding difficulties. Caregivers considered that the symptom attention-deficit/hyperactivity disorder were most worrisome. Both series also reported sleep disturbance. Recently, anxiety has been reported in individuals with DDX3X variants. We strongly suggest that attention-deficit/hyperactivity disorder, anxiety, and sleep disorders need to be treated.

Maternal vitamin K deficient embryopathy: association with hyperemesis gravidarum and Crohn disease.

Chondrodysplasia punctata (CDP) is an etiologically heterogeneous disorder characterized by the radiographic finding of stippled epiphyses (punctate calcifications). It is often accompanied by a characteristic facial appearance, known as the Binder phenotype, which is attributed to hypoplasia of the nasal cartilages; abnormal distal phalanges (brachytelephalangy) are a common component manifestation as well. We report eight patients with a Binder phenotype with or without CDP who all shared a known or suspected maternal deficiency of vitamin K. We suspect that this phenotype is probably under recognized, and we hope to increase awareness about the maternal risk factors, especially hyperemesis gravidarum, which lead to nutritional deficiency.

EFTUD2 haploinsufficiency leads to syndromic oesophageal atresia.

BACKGROUND: Oesophageal atresia (OA) and mandibulofacial dysostosis (MFD) are two congenital malformations for which the molecular bases of syndromic forms are being identified at a rapid rate. In particular, the EFTUD2 gene encoding a protein of the spliceosome complex has been found mutated in patients with MFD and microcephaly (MIM610536). Until now, no syndrome featuring both MFD and OA has been clearly delineated. RESULTS: We report on 10 cases presenting with MFD, eight of whom had OA, either due to de novo 17q21.31 deletions encompassing EFTUD2 and neighbouring genes or de novo heterozygous EFTUD2 loss-of-function mutations. No EFTUD2 deletions or mutations were found in a series of patients with isolated OA or isolated oculoauriculovertebral spectrum (OAVS). CONCLUSIONS: These data exclude a contiguous gene syndrome for the association of MFD and OA, broaden the spectrum of clinical features ascribed to EFTUD2 haploinsufficiency, define a novel syndromic OA entity, and emphasise the necessity of mRNA maturation through the spliceosome complex for global growth and within specific regions of the embryo during development. Importantly, the majority of patients reported here with EFTUD2 lesions were previously diagnosed with Feingold or CHARGE syndromes or presented with OAVS plus OA, highlighting the variability of expression and the wide range of differential diagnoses.