Roberts Syndrome Research Articles

Limb reduction in an Esco2 cohesinopathy mouse model is mediated by p53-dependent apoptosis and vascular disruption

Roberts syndrome (RBS) is an autosomal recessive disorder with profound growth deficiency and limb reduction caused by ESCO2 loss-of-function variants. Here, we elucidate the pathogenesis of limb reduction in an Esco2fl/fl;Prrx1-CreTg/0 mouse model using bulk- and single-cell-RNA-seq and gene co-expression network analyses during embryogenesis. Our results reveal morphological and vascular defects culminating in hemorrhage of mutant limbs at E12.5. Underlying this abnormal developmental progression is a pre-apoptotic, mesenchymal cell population specific to mutant limb buds enriched for p53-related signaling beginning at E9.5. We then characterize these p53-related processes of cell cycle arrest, DNA damage, cell death, and the inflammatory leukotriene signaling pathway in vivo. In utero treatment with pifithrin-α, a p53 inhibitor, rescued the hemorrhage in mutant limbs. Lastly, significant enrichments were identified among genes associated with RBS, thalidomide embryopathy, and other genetic limb reduction disorders, suggesting a common vascular etiology among these conditions.

Fdo1, Fkh1, Fkh2, and the Swi6-Mbp1 MBF complex regulate Mcd1 levels to impact eco1 rad61 cell growth in Saccharomyces cerevisiae.

Cohesins promote proper chromosome segregation, gene transcription, genomic architecture, DNA condensation, and DNA damage repair. Mutations in either cohesin subunits or regulatory genes can give rise to severe developmental abnormalities (such as Robert Syndrome and Cornelia de Lange Syndrome) and also are highly correlated with cancer. Despite this, little is known about cohesin regulation. Eco1 (ESCO2/EFO2 in humans) and Rad61 (WAPL in humans) represent two such regulators but perform opposing roles. Eco1 acetylation of cohesin during S phase, for instance, stabilizes cohesin-DNA binding to promote sister chromatid cohesion. On the other hand, Rad61 promotes the dissociation of cohesin from DNA. While Eco1 is essential, ECO1 and RAD61 co-deletion results in yeast cell viability, but only within a limited temperature range. Here, we report that eco1rad61 cell lethality is due to reduced levels of the cohesin subunit Mcd1. Results from a suppressor screen further reveals that FDO1 deletion rescues the temperature-sensitive (ts) growth defects exhibited by eco1rad61 double mutant cells by increasing Mcd1 levels. Regulation of MCD1 expression, however, appears more complex. Elevated expression of MBP1, which encodes a subunit of the MBF transcription complex, also rescues eco1rad61 cell growth defects. Elevated expression of SWI6, however, which encodes the Mbp1-binding partner of MBF, exacerbates eco1rad61 cell growth and also abrogates the Mpb1-dependent rescue. Finally, we identify two additional transcription factors, Fkh1 and Fkh2, that impact MCD1 expression. In combination, these findings provide new insights into the nuanced and multi-faceted transcriptional pathways that impact MCD1 expression.

Complex cerebrovascular diseases in Roberts syndrome caused by novel biallelic ESCO2 variations.

Roberts syndrome (RBS), also known as Roberts-SC phocomelia syndrome, is a rare autosomal recessive developmental disorder caused by mutations in the ESCO2 gene. Cardinal clinical manifestations are pre- and postnatal growth retardation and craniofacial and limb malformations. Here, we report RBS in a Chinese adolescent with novel biallelic ESCO2 variations and complex cerebrovascular diseases. Medical history, neurological examinations, neuroimaging, and pathology were collected in the proband and the family. Whole exome sequencing (WES) with copy number variation analysis was performed to screen for genetic variations. The clinical features of the proband were craniofacial and limb malformations together with complex cerebrovascular diseases. She suffered ischemic stroke at 6 years old and died of cerebellar hemorrhage secondary to an aneurysm at 13 years old. Besides, neuroimaging showed the triad of leukoencephalopathy, calcifications, and cysts. Brain histopathology revealed angiomatous changes and perivascular cysts suggesting chronic small cerebral vasculopathy. Whole exome sequencing (WES) identified novel biallelic variations in the ESCO2 gene (c.1220A>T, p.H407L and c.1562delC, p.A521fs). We describe complex cerebrovascular diseases in Roberts syndrome caused by novel ESCO2 biallelic variations. This case expands not only the cerebral involvement in Roberts syndrome but also the disease spectrum of the neuroimaging triad with leukoencephalopathy, calcifications, and cysts.

Understanding complex begins with knowing the simple

Diagnosing rare genetic disorders is clinically challenging. Patients undergo extensive investigations, including multiple genetic/genomic tests. Despite being seen by several specialists, they often remain without a genetic diagnosis. A 4-year-old female with consanguineous parents presents with skeletal abnormalities, dysmorphism, global developmental delay, slow growth, and recurrent severe systemic infections. Initial next generation sequencing based primary immunodeficiency gene panel and SNP microarray detected no causative pathogenic variants. The final diagnosis was possible only following a special cytogenetic test, C-banded karyotype, which revealed heterochromatin repulsion and premature centromere separation in all metaphases, suggestive of Roberts syndrome (RS). RS/ESCO2-spectrum disorder is a rare autosomal recessive disorder caused by biallelic loss of function variants in the ESCO2 gene, with only 150 cases reported to date. Microarray analysis also showed long contiguous stretches of homozygosity at the 8p21 locus, which encompasses the ESCO2 gene. ESCO2 gene sequencing was recommended for molecular confirmation of the diagnosis. This case illustrates the importance of appropriate selection of genomic tests and highlights the critical role of karyotyping (including the use of specialized stains) in the diagnosis of some rare genetic disorders.

Robert Syndrome in an Indian Neonate

Robert Syndrome in an Indian Neonate

A multimodal genetic testing approach to a diagnosis of Roberts-SC phocomelia syndrome, an ESCO2 spectrum disorder

Abstract Diagnosis of a genetic syndrome has traditionally relied upon the identification of characteristic phenotypic findings, followed by targeted laboratory testing. Shared clinical manifestations between genetically distinct syndromes and variable expressivity of findings within a single syndrome can complicate the diagnosis. Multiple testing modalities may be necessary, even when the putative gene(s) is known. We describe the multi-pronged genetic testing applied to a patient with a suspected diagnosis of Roberts- SC phocomelia syndrome (RBS). RBS is an autosomal recessive developmental disorder (OMIM 268300) caused by pathogenic variants in the “establishment of sister chromatid cohesion N-acetyltransferase” (ESCO2 ) gene mapped to chromosome 8p21.1. The ESCO2 enzyme product is a conserved protein with acetyltransferase activity required for formation of the cohesin complex, which, among other activities, maintains sister chromatid association during S-phase of the cell cycle. Because of the defective cohesin complex, RBS joins other syndromes referred to as cohesinopathies. The patient, a newborn male, was small for gestational age, with hypertelorism, cleft lip and palate, shortened forearms, absence of the radius and thumbs, and bilateral clubbed feet. All of these findings are established characteristics of RBS. Targeted Next Generation Sequencing revealed a single variant in exon 10 of ESCO2 (c.1654C>T, p.Arg552*) predicted to result in a loss of function. Chromosomal microarray was also performed and showed an estimated 15 Mb region of homozygosity (ROH) extending from 8p11.21 to 8p21.2, which spans ESCO2. The finding of this ROH supported the interpretation of homozygosity for the variant, as did a family history of consanguinity. Additional cytogenetic analysis documented premature sister chromatid separation and repulsion of heterochromatin chromosomal regions characteristic of RBS. These chromosomal findings served as a functional assay supporting pathogenicity of the ESCO2 variant. Interestingly, the only report of an identical variant within exon 10 of ESCO2 was described for two brothers diagnosed with Juberg-Hayward syndrome. Juberg-Hayward was considered allelic to, but a distinct entity from RBS. In contrast, our findings support the conclusion that RBS and Juberg-Hayward are not distinct syndromes, but rather represent variability within an ESCO2 syndrome spectrum. Such unification of diagnoses based on genomic findings has influenced numerous other clinical disorders. Further, our findings demonstrate the contributions of each of the genetic testing modalities, which may be applied, selectively or collectively, based on integration with clinical and family history data.

CLINICAL AND MOLECULAR RESULTS OF SIX CASES WITH ROBERTS SYNDROME: REVIEW OF CASES FROM TURKIYE

Objective: Roberts syndrome is a rare autosomal recessive disease characterized by limb defects, prenatal onset growth retardation, and craniofacial anomalies. We aimed to compare the clinical and molecular findings of six cases with Roberts syndrome with the previously reported patients from Turkiye and to emphasize that a definitive diagnosis can be made in the intrauterine period with cytogenetic tests in the early period without the need to wait for molecular test results. Materials and Methods: Six cases, diagnosed with Roberts syndrome, in our outpatient clinic of Istanbul University, Istanbul Faculty of Medicine, Medical Genetics Department between 2015-2021, were included in the study. The family history, clinical information, and cytogenetic and molecular findings of the patients were retrospectively reviewed and compared with the cases reported from Turkiye in the literature. G and C-banding techniques and Sanger sequencing of the ESCO2 gene were performed. Results: Pathogenic variants in homozygous in four and compound heterozygous in two patients in the ESCO2 gene were identified. Compound heterozygous c.[417dup];[1131+1G>A] (p.[(Pro140Thrfs*8)];[(?)]) in case 1, and c.[1111dup];[760del] (p. [(Thr371Asnfs*32)];[(Thr254Leufs*13)]) in case 6, homozygous c.1131+1G>A (p.(?)) in case 2, case 3 and case 5, and homozygous c.1111dup (p.(Thr371Asnfs*32)) in case 4 were detected. The variants reported in our case series were previously associated with the disease. The first demonstration of the c.760del in a Turkish case contributed to the genetic association of this pathogenic variants with Roberts syndrome Although all the previously reported patients were homozygous, we have detected two patients with compound heterozygous pathogenic alterations from Turkiye indicating that the disease should also be considered in families with no consanguinity.

A child with Roberts syndrome presenting severe craniofacial anomaly

Roberts syndrome is a rare congenital anomaly which was described by John Roberts in 1919, also known as pseudothalidomidic or phocomelia. Characterized by skeletal deformities, in particular symmetric reduction of the extremities and craniofacial anomalies such as cleft lip and palate and cranio synostosis presenting more frequently, as well as bilateral symmetric short neck tetraphocomelia or hypomelia and brachydactyly. Its prevalence is unclear. As of now, 150 cases of different racial and ethnic origins have been reported in the literature. The diagnosis of Roberts Syndrome is established by cytogenetic and molecular analysis which show a phenomenon known as premature separation of the centromere or heterochromatin repulsion, constituting the main marker for Roberts syndrome. For any child with limb and craniofacial bone malformations, this syndrome should be considered as a differential diagnosis. The purpose of this study is to present a clinical case of a 2-year-old patient with Roberts Syndrome with a marked craniofacial anomaly.

G1-Cyclin2 (Cln2) promotes chromosome hypercondensation in eco1/ctf7 rad61 null cells during hyperthermic stress in Saccharomyces cerevisiae.

Eco1/Ctf7 is a highly conserved acetyltransferase that activates cohesin complexes and is critical for sister chromatid cohesion, chromosome condensation, DNA damage repair, nucleolar integrity, and gene transcription. Mutations in the human homolog of ECO1 (ESCO2/EFO2), or in genes that encode cohesin subunits, result in severe developmental abnormalities and intellectual disabilities referred to as Roberts syndrome and Cornelia de Lange syndrome, respectively. In yeast, deletion of ECO1 results in cell inviability. Codeletion of RAD61 (WAPL in humans), however, produces viable yeast cells. These eco1 rad61 double mutants, however, exhibit a severe temperature-sensitive growth defect, suggesting that Eco1 or cohesins respond to hyperthermic stress through a mechanism that occurs independent of Rad61. Here, we report that deletion of the G1 cyclin CLN2 rescues the temperature-sensitive lethality otherwise exhibited by eco1 rad61 mutant cells, such that the triple mutant cells exhibit robust growth over a broad range of temperatures. While Cln1, Cln2, and Cln3 are functionally redundant G1 cyclins, neither CLN1 nor CLN3 deletions rescue the temperature-sensitive growth defects otherwise exhibited by eco1 rad61 double mutants. We further provide evidence that CLN2 deletion rescues hyperthermic growth defects independent of START and impacts the state of chromosome condensation. These findings reveal novel roles for Cln2 that are unique among the G1 cyclin family and appear critical for cohesin regulation during hyperthermic stress.

Prenatal Diagnosis and Management of Thrombocytopenia-Absent Radius Syndrome.

Prenatal Diagnosis and Management of Thrombocytopenia-Absent Radius Syndrome.

Prenatal diagnosis of Roberts syndrome in a Chinese family based on ultrasound findings and whole exome sequencing: a case report

BackgroundRoberts syndrome (RBS) is a rare autosomal recessive disorder caused by variations in the ESCO2 gene; however, prenatal diagnosis of RBS has never been reported in Chinese families. Additionally, fetal-specific phenotypic characteristics associated with ESCO2 variants have not been reported.Case presentationA fetus in a healthy, nonconsanguineous Chinese family with multiple serious congenital malformations was diagnosed prenatally. Two consecutive fetuses in this family presented with tetraphocomelia, growth restriction, cleft lip and palate bilaterally, and other abnormalities. The main phenotypic characteristics of this case were strongly suspected to be associated with RBS. Finally, whole exome sequence analysis revealed the insertion of a homozygous base pair in exon 6 of the ESCO2 gene (NM_001017420.3, c.1111insA, NP_001017420.1, p.Thr371fs). Both of the couples were heterozygous carriers for this variant.ConclusionWe are the first to report a prenatal case of RBS diagnosed in a Chinese family. Here, we have confirmed that the rare variant is a definite pathogenic variant, and we provide detailed phenotypic characteristics for the prenatal diagnosis of RBS due to this causative variant.

Esco2 and cohesin regulate CRL4 ubiquitin ligase ddb1 expression and thalidomide teratogenicity

ABSTRACT Cornelia de Lange syndrome (CdLS) and Roberts syndrome (RBS) are severe developmental maladies that arise from mutation of cohesin (including SMC3, CdLS) and ESCO2 (RBS). Though ESCO2 activates cohesin, CdLS and RBS etiologies are currently considered non-synonymous and for which pharmacological treatments are unavailable. Here, we identify a unifying mechanism that integrates these genetic maladies to pharmacologically-induced teratogenicity via thalidomide. Our results reveal that Esco2 and cohesin co-regulate the transcription of a component of CRL4 ubiquitin ligase through which thalidomide exerts teratogenic effects. These findings are the first to link RBS and CdLS to thalidomide teratogenicity and offer new insights into treatments.

Roberts syndrome with bilateral corneal opacity

Roberts syndrome (RBS) is a rare autosomal recessive genetic disorder. Mutation in the ESCO2 (establishment of cohesion 1 homologue 2) gene has been reported to cause disease. Patients with RBS may have many ophthalmologic pathologies such as hypertelorism, down slating palpebral fissures, corneal opacity, and congenital cataract. Here, we report the case of two siblings who were diagnosed with RBS and were followed in our clinic.

Craniofacial Anthropometry in Roberts Syndrome in a Sample of Egyptians

Craniofacial Anthropometry in Roberts Syndrome in a Sample of Egyptians

Genetically induced redox stress occurs in a yeast model for Roberts syndrome.

Roberts syndrome (RBS) is a multispectrum developmental disorder characterized by severe limb, craniofacial, and organ abnormalities and often intellectual disabilities. The genetic basis of RBS is rooted in loss-of-function mutations in the essential N-acetyltransferase ESCO2 which is conserved from yeast (Eco1/Ctf7) to humans. ESCO2/Eco1 regulate many cellular processes that impact chromatin structure, chromosome transmission, gene expression, and repair of the genome. The etiology of RBS remains contentious with current models that include transcriptional dysregulation or mitotic failure. Here, we report evidence that supports an emerging model rooted in defective DNA damage responses. First, the results reveal that redox stress is elevated in both eco1 and cohesion factor Saccharomyces cerevisiae mutant cells. Second, we provide evidence that Eco1 and cohesion factors are required for the repair of oxidative DNA damage such that ECO1 and cohesin gene mutations result in reduced cell viability and hyperactivation of DNA damage checkpoints that occur in response to oxidative stress. Moreover, we show that mutation of ECO1 is solely sufficient to induce endogenous redox stress and sensitizes mutant cells to exogenous genotoxic challenges. Remarkably, antioxidant treatment desensitizes eco1 mutant cells to a range of DNA damaging agents, raising the possibility that modulating the cellular redox state may represent an important avenue of treatment for RBS and tumors that bear ESCO2 mutations.

An ever-changing landscape in Roberts syndrome biology: Implications for macromolecular damage.

Roberts syndrome (RBS) is a rare developmental disorder that can include craniofacial abnormalities, limb malformations, missing digits, intellectual disabilities, stillbirth, and early mortality. The genetic basis for RBS is linked to autosomal recessive loss-of-function mutation of the establishment of cohesion (ESCO) 2 acetyltransferase. ESCO2 is an essential gene that targets the DNA-binding cohesin complex. ESCO2 acetylates alternate subunits of cohesin to orchestrate vital cellular processes that include sister chromatid cohesion, chromosome condensation, transcription, and DNA repair. Although significant advances were made over the last 20 years in our understanding of ESCO2 and cohesin biology, the molecular etiology of RBS remains ambiguous. In this review, we highlight current models of RBS and reflect on data that suggests a novel role for macromolecular damage in the molecular etiology of RBS.

Roberts sendromu olgusu: Ultrasonografik özellikleri ve genetik tanısı

Objective: Roberts syndrome is a very rare genetic disease, and it has an autosomal recessive inheritance pattern. It develops as a result of the mutation in ESCO2 gene located in the 8th chromosome. In our study, we aimed to present a case which was found to have Roberts syndrome coexisting with multiple anomalies, particularly skeletal system anomaly, in the 17 weeks of gestation. Case(s): In the fetal ultrasonographic evaluation performed on the pregnant women who referred to our hospital for routine gestational examination in the 17 weeks of gestation, anomalies in the bilateral upper and lower extremities, contracted legs, bilateral cleft palate and lip, intrauterine growth restriction and cardiac anomaly were found in the fetus. Roberts syndrome was considered first with these ultrasonographic findings. The diagnosis of Roberts syndrome was confirmed by cytogenetic and molecular analyses. Early segregation of centromeres and early breaking up of heterochromatic regions near centromeres were found at metaphase stage. By cytogenetic and molecular analyses, homozygous mutation in ESCO2 gene of the fetus and heterozygous mutation in the parents were found. The termination of pregnancy was decided after the genetic consultation with the parents. Physical examination findings and prenatal ultrasound findings after termination were found similar. Conclusion: Many severe skeletal dysplasia cases can be diagnosed ultrasonographically before 20 weeks of gestation. Early diagnosis ensures to take necessary actions for medical support during postnatal period and in terms of labor if pregnancy continues as well as genetic consultation opportunity. If the genetic disease that causes skeletal dysplasia can be identified and parents are found to have this gene, healthy pregnancies can be achieved by obtaining normal embryos via pre-implantation genetic diagnosis in order to prevent the relapse of the disease.

Pseudo-Roberts Syndrome: An Entity or Not?

Background: Roberts syndrome is a genetic disorder characterized by tetra-phocomelia with abnormalities of ESCO2. We report a male stillborn with tetra-phocomelia and no ESCO2 mutation. Case report: Pre- and post-natal imaging and autopsy findings included schizencephaly, phocomelia of four limbs, micrognathia, oligodactyly, and cardiopulmonary malformations. Microcephaly on pre-natal imaging was not confirmed by autopsy examination. Karyotype, prenatal chromosome microarray and ESCO2 gene testing were normal. Conclusion: Given the various skeletal anomalies found on autopsy and imaging evaluations, at least phenotypically, our case appeared to conform into Roberts syndrome spectrum. Since the infant did not have the mutation associated with this disorder, this infant could be labeled as the first report of a pseudo-Roberts syndrome because many of his phenotypic anomalies are characteristic of Roberts syndrome in absence of the ESCO2 gene mutation.

VP32.17: Bilateral symmetric tetraphocomelia: antenatal clue to Roberts syndrome – a case report

VP32.17: Bilateral symmetric tetraphocomelia: antenatal clue to Roberts syndrome – a case report

Juberg-Hayward syndrome and Roberts syndrome are allelic, caused by mutations in ESCO2

ObjectiveJuberg-Hayward syndrome (JHS; MIM 216100) is a rare autosomal recessive malformation syndrome, characterized by cleft lip/palate, microcephaly, ptosis, hypoplasia or aplasia of thumbs, short stature, dislocation of radial head, and fusion of humerus and radius leading to elbow restriction. A homozygous mutation in ESCO2 has recently been reported to cause Juberg-Hayward syndrome. Our objective was to investigate the molecular etiology of Juberg-Hayward syndrome in two affected Lisu tribe brothers. Materials and MethodsTwo patients, the unaffected parents, and two unaffected siblings were studied. Clinical and radiographic examination, whole exome sequencing, Sanger sequencing, Western blot analysis, and chromosome testing were performed. ResultsTwo affected brothers had characteristic features of Juberg-Hayward syndrome, except for the absence of microcephaly. The elder brother had bilateral cleft lip and palate, short stature, humeroradial synostosis, and simple partial seizure with secondary generalization. The younger brother had unilateral cleft lip and palate, short stature, and dislocation of radial heads. The homozygous (c.1654C > T; p.Arg552Ter) mutation in ESCO2 was identified in both patients. The other unaffected members of the family were heterozygous for the mutation. The presence of humeroradial synostosis and radial head dislocation in the same family is consistent with both being in the same spectrum of forearm malformations. Chromosome testing of the affected patients showed premature centromere separation. Western blot analysis showed reduced amount of truncated protein. ConclusionOur findings confirm that a homozygous mutation in ESCO2 is the underlying cause of Juberg-Hayward syndrome. Microcephaly does not appear to be a consistent feature of the syndrome.