Rubinstein-Taybi Syndrome Research Articles

Transcriptome and acetylome profiling identify crucial steps of neuronal differentiation in Rubinstein-Taybi syndrome

Rubinstein-Taybi syndrome (RTS) is a rare and severe genetic developmental disorder characterized by multiple congenital anomalies and intellectual disability. CREBBP and EP300, the two genes known to cause RTS encode transcriptional coactivators with a catalytic lysine acetyltransferase (KAT) activity. Loss of CBP or p300 function results in a deficit in protein acetylation, in particular at histones. In RTS, nothing is known on the consequences of the loss of histone acetylation on the transcriptomic profiles during neuronal differentiation. To address this question, we differentiated induced pluripotent stem cells from RTS patients carrying a recurrent CREBBP mutation that inactivates the KAT domain into cortical and pyramidal neurons. By comparing their acetylome and their transcriptome at different neuronal differentiation time points, we identified 25 specific acetylated histone residues altered in RTS. We also identified the transition between neural progenitors and immature neurons as a critical step of the differentiation process, with a delayed neuronal maturation in RTS. Overall, this study opens new perspectives in the definition of epigenetic biomarkers for RTS, whose methodology could be extended to other chromatinopathies.

A rare case of a patient with Rubinstein-Taybi syndrome and acute lymphoblastic leukaemia

A rare case of a patient with Rubinstein-Taybi syndrome and acute lymphoblastic leukaemia

History Page: Leaders in MSK Radiology: Hooshang Taybi, 1919-2006.

This history page is dedicated to the memory and achievements of the pediatric radiologist Hooshang Taybi whose name is associated with the Rubinstein-Taybi syndrome, Taybi syndrome, and Taybi-Linder syndrome.

Rubinstein-Taybi Syndrome Clinical Characteristics from the Perspective of Quality of Life and the Impact of the Disease on Family Functioning.

Background/Objectives: Rubinstein-Taybi Syndrome (RSTS-OMIM, #180849) is a rare genetic disorder associated with distinctive clinical features, including a typical craniofacial appearance, global developmental delay, intellectual disability and broad, angular thumbs and fingers. The main aim of the study was to evaluate the health problems of children with RTST, their quality of life and the impact of the disease on family functioning. In addition, we investigate whether comorbidities, autistic behavior and eating problems affect the children's overall QOL. Methods: A cross-sectional study was performed, including a total of 13 caregivers of children diagnosed with RSTS. A self-reported questionnaire [SRQ], medical records and the Pediatric Impact Module PedsQLTM 2.0, the Pediatric Quality of Life PedsQLTM 4.0 were used to obtain data on QOL and the impact of the disease on family functioning. Results: The overall QOL score for children with RSTS was x = 52.40; SD 13.01. The highest QOL was in emotional functioning (EF; x = 59.23; SD 18.69), while the lowest QOL was in physical functioning (PF; x = 48.56; SD 16.32) and social functioning (SF; x = 48.85; SD 18.84). There was a statistically significant negative correlation (p < 0.03; r = -2.01) between the age of the child and their QOL, indicating that older children had lower QOL scores. The mean overall rating for the impact of RSTS on family functioning was x = 50.00; SD 10.91. Caregivers reported the highest scores for cognitive functioning (CF; x = 64.23; SD 23.70) and family relationships (FR; x = 60.00; SD 17.17). The lowest scores were for daily activities (DA; x = 41.03; SD 17.17) and worry (W; x = 37.69; SD 18.55). Conclusions: This study provides the first comprehensive exploration of the QOL of children with RSTS) and its impact on family functioning.

Neurosurgical Management of Rubinstein-Taybi Syndrome: An Institutional Experience

Introduction: Rubinstein-Taybi syndrome (RTS) is a rare genetic condition with a distinctive set of physical features. This case series reports a single institutional experience of RTS cases, highlighting the role of neurosurgery in the comprehensive management of RTS patients. Methods: A retrospective review of patients with genetically confirmed RTS presenting between 2010 and 2023 at Children’s Hospital of Pittsburgh was performed. Patient demographics, genetic profile, clinical symptoms, radiographic characteristics, and neurosurgical management were recorded for all patients. Results: Twenty-one patients (13 females, 8 males) aged 0 to 22 years presented for formal genetic counseling and diagnosis. Twenty patients (95%) had CREBBP pathogenic variants (RTS type 1), and 1 patient (5%) had EP300 pathogenic variants (RTS type 2). Ten patients (48%) had a low-lying conus medullaris, and 3 patients (30%) underwent subsequent spinal cord detethering. Four patients (19%) had a Chiari malformation, and three (75%) underwent Chiari decompression surgeries. One patient (5%) had Chiari-associated syringomyelia. Conclusions: RTS patients have an increased rate of tethered cord syndrome requiring detethering. The incidence of symptomatic Chiari I malformation requiring decompression has not been previously reported. The RTS series presented here demonstrates a high incidence of symptomatic Chiari I malformation in addition to tethered cord syndrome.

Prenatal diagnosis of a fetus with Rubinstein-Taybi syndrome

To explore the clinical characteristics and variant of CREBBP gene in a fetus with Rubinstein-Taybi syndrome (RSTS). A fetus with RSTS diagnosed at the Third Affiliated Hospital of Zhengzhou University in August 2022 was selected as the study subject. Clinical data, amniotic fluid sample of the fetus and peripheral blood samples of its parents were collected for whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing. Foot malformation, cerebellar vermis agenesis, brain agenesis, polysyndactyly of the big toes and other phenotypes were found by prenatal ultrasound. WES revealed that the fetus has harbored a heterozygous c.4684G>T (p.E1562*) variant in exon 28 of the CREBBP gene (NM_004380.3), which was de novo in origin. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was predicted to be pathogenic (PVS1+PS2_Moderate+PM2_Supporting). After genetic counseling, the couple had opted to terminate the pregnancy and refused autopsy of the fetus. The c.4684G>T (p.E1562*) variant of the CREBBP gene probably underlay the RSTS in this fetus. The newly discovered variant has enriched the mutational spectrum of the CREBBP gene and illustrated that WES is an efficient tool for the prenatal diagnosis of RSTS.

Epigenetics in rare neurological diseases.

Rare neurological diseases include a vast group of heterogenous syndromes with primary impairment(s) in the peripheral and/or central nervous systems. Such rare disorders may have overlapping phenotypes, despite their distinct genetic etiology. One unique aspect of rare neurological diseases is their potential common association with altered epigenetic mechanisms. Epigenetic mechanisms include regulatory processes that control gene expression and cellular phenotype without changing the composition of the corresponding DNA sequences. Epigenetic factors include three types of proteins, the "readers, writers, and erasers" of DNA and DNA-bound proteins. Thus, epigenetic impairments of many neurological diseases may contribute to their pathology and manifested phenotypes. Here, we aim to provide a comprehensive review on the general etiology of selected rare neurological diseases, that include Rett Syndrome, Prader-Willi Syndrome, Rubinstein-Taybi Syndrome, Huntington's disease, and Angelman syndrome, with respect to their associated aberrant epigenetic mechanisms.

The functional secondary effect after an integrated rehabilitative intervention to learn reading and writing in a girl with Rubinstein-Taybi syndrome.

A case report of a six-year and five-month-old female admitted with typical symptoms of Rubinstein-Taybi syndrome is presented. Clinical and rehabilitation settings where she acquired her reading, writing, and communication skills are described. Because of her cognitive disabilities, a multidisciplinary and long-term intervention (2014-2020) was necessary. Treatment included orthoptic, psychomotor, logopedic, occupational, and neuropsychological care. Her family and school were involved. Increased attention led to decreased dysfunctional behaviors. Test results are still below average, but there has been significant improvement. Better communication skills resulted from increased phonetic range, improved articulation, lexical-semantic structure, comprehension, and production of sentences. Digital technologies played a significant role in enhancing her communication skills, not just in social interactions but also in school activities. The patient is oriented in time and space with the help of agendas and calendars. She can express her needs and compose concise narratives. As a result of acquiring functional skills, she is better equipped to handle real-life situations, which has led to increased social and family activities. This case report highlights the importance of personalized rehabilitation programs. Obtaining an early genetic diagnosis is crucial for timely tailored rehabilitation, and any delays in this process can hinder progress.

Generation of an induced pluripotent stem cell line IGIBi18-A from an Indian patient with Rubinstein Taybi Syndrome

Rubinstein Taybi Syndrome (RSTS) is a rare genetic disorder which is caused by mutations in either CREBBP or EP300. RSTS with mutations in CREBBP is known as RSTS-1. We have generated an induced pluripotent stem cell (iPSC) line, IGIBi018-A from an Indian RSTS-patient using the episomal reprogramming method. The CREBBP gene in the patient harbours a nonsense mutation at position NM_004380.3(c.6876 del C). IGIBi018-A iPSC showed expression of pluripotent stem cell markers, has a normal karyotype and could be differentiated into three germ layers. This iPSC line will help to explore the role of CREBBP in RSTS associated developmental defects.

Lacrimal Drainage Anomalies in Goldenhar, Rubinstein-Taybi, and Ectodermal-Ectrodactyly-Clefting Syndromes.

To describe in detail the lacrimal drainage system anomalies and review of literature in patients with Goldenhar syndrome, Rubinstein-Taybi syndrome (RTS), and Ectodermal-Ectrodactyly-Clefting syndrome (EECS), their management and outcomes. A retrospective chart review from January 2011-June 2023 of all cases presenting to the Dacryology clinic with Goldenhar syndrome, RTS, and EECS was obtained. Data collected included demographics, laterality, clinical presentations, proximal and distal lacrimal drainage anomalies, associated systemic features, management, and outcomes. Eight children with Goldenhar syndrome (n = 13), three with RTS (n = 5) and three with EECS (n = 5) presented with lacrimal drainage system involvement. Cases with Goldenhar syndrome showed male predominance (5/8), and the mean age at presentation was 14.75 months. Four cases had simple CNLDO, seven cases with complex CNLDO (4 - buried probe and 3 - atonic sacs) and a single neonate presented with bilateral dacryocele. Patients with RTS presented with mean age of 36.33 months with male predominance. Probing under endoscopic guidance explored the anatomy thoroughly and those with altered nasal anatomy increased the probability of complex CNLDO. Those with EECS (n = 5) presented with a greater involvement of proximal lacrimal drainage system compared with Goldenhar syndrome and RTS, including anomalies like punctal agenesis, incomplete punctal canalization (IPC), ectopic puncta, canalicular stenosis, and complex CNLDO. A step-wise approach to assessing the proximal and lacrimal drainage system in those affected with craniofacial malformations and addressing them can result in satisfactory outcomes for the majority of patients.

Characterization of a novel HDAC2 pathogenetic variant: a missing puzzle piece for chromatinopathies

Histone deacetylases (HDACs) are enzymes pivotal for histone modification (i.e. acetylation marks removal), chromatin accessibility and gene expression regulation. Class I HDACs (including HDAC1, 2, 3, 8) are ubiquitously expressed and they often participate in multi-molecular protein complexes. To date, three neurodevelopmental disorders caused by mutations in genes encoding for HDACs (HDAC4, HDAC6 and HDAC8) and thus belonging to the group of chromatinopathies, have been described. We performed whole exome sequencing (WES) for a patient (#249) clinically diagnosed with the chromatinopathy Rubinstein-Taybi syndrome (RSTS) but negative for mutations in RSTS genes, identifying a de novo frameshift variant in HDAC2 gene. We then investigated its molecular effects in lymphoblastoid cell lines (LCLs) derived from the patient compared to LCLs from healthy donors (HD). As the variant was predicted to be likely pathogenetic and to affect the sequence of nuclear localization signal, we performed immunocytochemistry and lysates fractionation, observing a nuclear mis-localization of HDAC2 compared to HD LCLs. In addition, HDAC2 total protein abundance resulted altered in patient, and we found that newly identified variant in HDAC2 affects also acetylation levels, with significant difference in acetylation pattern among patient #249, HD and RSTS cells and in expression of a known molecular target. Remarkably, RNA-seq performed on #249, HD and RSTS cells shows differentially expressed genes (DEGs) common to #249 and RSTS. Interestingly, our reported patient was clinically diagnosed with RSTS, a chromatinopathy which known causative genes encode for enzymes antagonizing HDACs. These results support the role of HDAC2 as causative gene for chromatinopathies, strengthening the genotype-phenotype correlations in this relevant group of disorders.

Rubinstein Taybi syndrome with secondary glaucoma: An unusual case report and review of literature

Rubinstein Taybi syndrome is a rare neurodevelopmental disorder characterized by broad thumbs and first toe, microcephaly, developmental delay, beaked nose, talon cusps, and various systemic abnormalities like cardiac defects, hearing loss, respiratory infections, and ocular abnormalities which are common with this syndrome. The various ocular abnormalities reported in the literature are corneal opacities, lacrimal gland abnormalities, strabismus, coloboma, retinal dysfunction, and congenital glaucoma. We hereby report the case of a 7-year-old boy who presented in the glaucoma clinic of a tertiary eye care center with large eyeballs and a typical dysmorphic face characterized by high-arched brows with a low-hanging columella, grimacing smile, talon cusps, diffuse corneal haze, and enlarged corneal diameters (12.5 mm) and who was subsequently diagnosed with congenital glaucoma after evaluation under anesthesia (EUA). EUA revealed raised intraocular pressure (IOP) of 22 mmHg, and optic never head cupping in the right eye (RE) was 0.8:1 the other eye had a total leucomatous corneal opacity. The child was started on topical antiglaucoma medication in RE, and subsequent evaluation revealed well-controlled IOP on these medications.

CRISPR/Cas9 genome editing clinical trials for neurodevelopmental disorders

IntroductionRecently, the new therapeutic approach based on genome editing using the CRISPR/Cas9 system has been applied to treat cancer and other monogenetic disorders. CRISPR/Cas9 allows specific correction of the altered gene without affecting the rest of the genome.ObjectivesThe aim of this study was to report the current CRISPR/Cas9 genome editing clinical trials in neurodevelopmental and mental disorders.Methods We conducted a search via the ClinicalTrials platform to describe clinical trials that have been conducted using the CRISPR/Cas9 genome-editing tool in neurodevelopmental disorders.Results Our research revealed three clinical trials that used the CRISPR/Cas9 tool for diagnostic and therapeutic purposes. The first study aimed to investigate the pathological role of KMT2D mutations in 40 Kabuki syndrome patients in order to facilitate the identification and characterization of therapeutic strategies to improve symptoms, to identify the consequences of KMT2D mutations on epigenetic marker changes and cellular structural changes and to finally attempt gene correction by CRISPR/Cas9. The therapeutic approach was an epigenome editing approach aimed at increasing the expression of the wild-type KMT2D allele to restore the functional activity of a histone H3-lysine 4 (H3K4)-methyltransferase (MLL4) in treated mesenchymal stem cells. The second clinical trial aimed to validate gene editing based on CRISPR/Cas9 technology combined with AAV delivery for the correction of the most common MECP2 mutations in Rett syndrome both in vitro and in vivo. The third GENEPI clinical trial aimed to identify acetylation profiles as epigenetic markers to assess the causality of CREBBP and EP300 variants in Rubinstein-Taybi syndrome, which is considered as a genetic model of neurodevelopmental abnormality with an epigenetic component.ConclusionsCRISPR/Cas9 clinical trials in polygenic conditions, such as psychiatric disorders, could be envisaged at the level of the epigenetic component of these pathologies. This therapy could be applied ex vivo to perform tissue-specific gene editing.Disclosure of InterestNone Declared

Menke-Hennekam syndrome; delineation of domain-specific subtypes with distinct clinical and DNA methylation profiles

CREB-binding protein (CBP, encoded by CREBBP) and its paralog E1A-associated protein (p300, encoded by EP300) are involved in histone acetylation and transcriptional regulation. Variants that produce a null allele or disrupt the catalytic domain of either protein cause Rubinstein-Taybi syndrome (RSTS), while pathogenic missense and in-frame indel variants in parts of exons 30 and 31 cause phenotypes recently described as Menke-Hennekam syndrome (MKHK). To distinguish MKHK subtypes and define their characteristics, molecular and extended clinical data on 82 individuals (54 unpublished) with variants affecting CBP (n=71) or p300 (n=11) (NP_004371.2 residues 1705-1875 and NP_001420.2 residues 1668-1833, respectively) were summarized. Additionally, genome-wide DNA methylation profiles were assessed in DNA extracted from whole peripheral blood from 54 individuals. Most variants clustered closely around the zinc binding residues of two zinc finger domains (ZZ and TAZ2) and within the first α-helix of the fourth intrinsically disordered linker (ID4) of CBP/p300. Domain-specific methylation profiles were discerned for the ZZ domain in CBP/p300 (found in 9/10 tested individuals) and TAZ2 domain in CBP (in 14/20), while a domain-specific diagnostic episignature was refined for the ID4 domain in CBP/p300 (in 21/21). Phenotypes including intellectual disability of varying degree, and distinct physical features were defined for each of the regions. These findings demonstrate existence of at least three MKHK subtypes, which are domain-specific (MKHK-ZZ, MKHK-TAZ2, and MKHK-ID4) rather than gene-specific (CREBBP/EP300). DNA methylation episignatures enable stratification of molecular pathophysiologic entities within a gene or across a family of paralogous genes.

Clinical and genetic characteristics of 21 children with Rubinstein-Taybi syndrome

Objective: To investigate the phenotypes of Rubinstein-Taybi syndrome (RSTS) caused by variants in the CREBBP or EP300 gene, and the correlation between genotype and phenotype. Methods: This case series study was performed on pediatric patients who were referred to the Children's Hospital of Capital Institute of Pediatrics between January 2013 and July 2022. Both point variant and copy number deletion in CREBBP or EP300 gene were detected by whole exome sequencing, chromosomal microarray analysis, or copy number variation sequencing (CNV-seq). The variant categories were summarized and phenotype numbers were re-visited for RSTS patients. Based on variant types, the patients were divided into different groups (point variant or copy number deletion, EP300 or CREBBP point variant, and loss of function or missense variant). Phenotype counts between different groups were compared using the rank-sum test of two independent samples. Results: A total of 21 RSTS patients were recruited, including 12 males and 9 females, with ages ranging from 1 month to 14 years and 2 months. Among them, 67% (14/21) had point variants, and 33% (7/21) had copy number deletions. Out of these, 20 variants (95%) were de novo. Among 20 patients finishing phenotype count during re-visit, 95% (19/20) of the patients exhibited developmental delays before the age of 2 years. Additionally, 80% (16/20) of the patients had distinctive facial features. Considering phenotype count, no statistically significant difference was found between point variant (14 cases) and copy number deletion (6 cases) (5.0 (3.0, 7.0) vs. 5.0 (2.5, 5.3), Z=0.75, P=0.452), CREBBP (10 cases) and EP300 gene (4 cases) point variant (5.0 (3.8, 7.0) vs. 4.0 (2.0, 6.0), Z=1.14, P=0.253), and loss of function (9 cases) and missense (5 cases) variant (6.0 (4.5, 7.0) vs. 3.0 (2.5, 5.5), Z=1.54, P=0.121). Conclusions: Patients with RSTS primarily exhibit developmental delays in early childhood. Specific facial features serve as suggested signs of genetic testing. However, no significant genotype-phenotype correlation is found.

The relationship between CREBBP variants and Insomnia: from Rubinstein-Taybi syndrome into energy metabolism

The relationship between CREBBP variants and Insomnia: from Rubinstein-Taybi syndrome into energy metabolism

A rare presentation of Rubinstein-Taybi syndrome

Objective. Taybi syndrome is a rare genetical disorder with the symptoms of small stature, broad thumbs and first toes, a moderate to severe intellectual handicap, and unique facial traits. The present case study aimed with diagnose and therapeutic management of pediatric patients having Rubinstein-Taybi syndrome. Study area. The case study was carried out in Jawaharlal Nehru Medical College, Acharya Vinoba Bhave Rural Hospital, Sawangi Meghe, Wardha, Maharashtra, in department of Pediatrics. The present study follows case of male child, diagnosed with different degrees of compliance, in which the therapeutic approach was determined by the severity of the patient’s conditions. Outcomes. Case study on 3 years old male child was carried out and observed with some behavioural changes like unstable mood, distractibility and impulsivity along with attention problem, aggressive nature and self-injurious behavior etc. As the syndrome does not have a particular treatment but some therapies are applied to address issues that are frequently connected to the illness. The thumbs or toes surgically repaired might enhance grip or ease pain. The study was performed as per the scientific way, based on research literatures study.

Sindromi, genetica e immunologia: dall’inizio della fine alla fine dell’inizio

Syndromic immunodeficiencies are defined as a group of immunodeficiencies in which the immunological defect may be found only in a subgroup of patients. They fall within a more complex clinical picture and may not represent the primary clinical problem (i.e. DiGeorge syndrome, ataxia-telangiectasia, CHARGE syndrome, Kabuki syndrome etc.). Along with well-known and recognized syndromic immunodeficiencies, immunological abnormalities have been recently described in genetic syndromes that were not previously considered as inborn errors of immunity. The paper describes the cases of two patients affected by two rare genetic syndromes, namely Jacobsen syndrome and Rubinstein-Taybi syndrome. In the first case, the immunological phenotype of Jacobsen syndrome has been expanded. In the second, the growing body of evidence has pointed out that patients with Rubinstein-Taybi syndrome may present with immunological abnormalities.

The relationship between neurodevelopmental transcriptional programs and insomnia: From Rubinstein-Taybi syndrome into energy metabolism

Neurodevelopmental disorders (NDD) are characterized by cognitive, emotional, and/or motor skills impairment since childhood, and sleep disturbances are a common comorbidity. Rubinstein-Taybi syndrome (RSTS), a rare genetic syndrome associated with NDD, is caused by CREBBP haploinsufficiency. This gene encodes an acetyltransferase with crucial role on the establishment of transcriptional programs during neurodevelopment. Although insomnia has been reported in RSTS patients, the convergent mechanisms between this sleep disturbance and CREBBP loss-of-function are not fully understood. We tested weather the genetic architecture underlying CREBBP regulatory targets and insomnia-associated genes is significantly shared. We then identified the biological pathways enriched among these shared genes. The intersection between CREBBP regulatory targets and genes associated with insomnia included 7 overlapping genes, indicating significantly more overlap than expected by chance. An over-representation analysis on these intersect genes identified pathways related to mitochondrial activity. This finding indicates that the transcriptional programs established by CREBBP might impact insomnia-related biological pathways through the modulation of energy metabolism. The overlapping gene set and biological pathways highlighted by this study may serve as a primer for new functional investigations of shared molecular mechanisms between insomnia and CREBBP regulatory targets.

Molecular insight into CREBBP and TANGO2 variants causing intellectual disability.

Intellectual disability (ID) can be associated with different syndromes such as Rubinstein-Taybi syndrome (RSTS) and can also be related to conditions such as metabolic encephalomyopathic crises, recurrent,with rhabdomyolysis, cardiac arrhythmias and neurodegeneration. Rare congenital RSTS1 (OMIM 180849) is characterized by mental and growth retardation, significant and duplicated distal phalanges of thumbs and halluces, facial dysmorphisms, and an elevated risk of malignancies. Microdeletions and point mutations in the CREB-binding protein (CREBBP) gene, located at 16p13.3, have been reported to cause RSTS. By contrast, TANGO2-related metabolic encephalopathy and arrhythmia (TRMEA) is a rare metabolic condition that causes repeated metabolic crises, hypoglycemia, lactic acidosis, rhabdomyolysis, arrhythmias and encephalopathy with cognitive decline. Clinicians need more clinical and genetic evidence to detect and comprehend the phenotypic spectrum of this disorder. Exome sequencing was used to identify the disease-causing variants in two affected families A and B from District Kohat and District Karak, Khyber Pakhtunkhwa. Affected individuals from both families presented symptoms of ID, developmental delay and behavioral abnormalities. The validation and co-segregation analysis of the filtered variant was carried out using Sanger sequencing. In the present study, two families (A and B) exhibiting various forms of IDs were enrolled. In Family A, exome sequencing revealed a novel missense variant (NM 004380.3: c.4571A>G; NP_004371.2: p.Lys1524Arg) in the CREBBP gene, whereas, in Family B, a splice site variant (NM 152906.7: c.605 + 1G>A) in the TANGO2 gene was identified. Sanger sequencing of both variants confirmed their segregation with ID in both families. The in silico tools verified the aberrant changes in the CREBBP protein structure. Wild-type and mutant CREBBP protein structures were superimposed and conformational changes were observed likely altering the protein function. RSTS and TRMEA are exceedingly rare disorders for which specific clinical characteristics have been clearly established, but more investigations are underway and required. Multicenter studies are needed to increase our understanding of the clinical phenotypes, mainly showing the genotype-phenotype associations.