Genetic and clinical heterogeneity in Korean patients with Rubinstein-Taybi syndrome

Rubinstein-Taybi syndrome with ganglioneuroblastoma: a case report and literature review

BACKGROUND

Rubinstein-Taybi syndrome (RSTS) is a rare genetic disorder characterized by severe global developmental delay (GDD) and distinctive facial grimacing. The loss of function of the CREBBP and EP300 genes is recognized as a genetic etiology of RSTS. However, the association between CREBBP variants and an increased risk of tumors remains unknown, despite multiple reports of tumor comorbidities related to RSTS. The aim of this study is to elucidate the tumors associated with CREBBP variants in the context of RSTS by presenting a case of ganglioneuroblastoma (GNB) in a patient diagnosed with RSTS.

CASE PRESENTATION

We describe a 9-month-old male patient exhibiting distinctive facial features, enorchia, and GDD. Whole exome sequencing (WES) revealed a de novo pathogenic variant in NM_004380 (CREBBP): c.1068del (p.Gln356Hisfs*33). At one year of age, the patient experienced an unexplained fever lasting for two months, and the definitive diagnosis of GNB was established.

CONCLUSIONS

We report a case of RSTS co-morbid with GNB and conduct phenotypic and genotypic analyses of 43 individuals with documented CREBBP variants and associated tumors in the literature. We observed that frameshift variations are common in malignancies among the individuals studied, while more microdeletions were noted in patients with benign tumors. Currently, there is insufficient evidence to support a correlation between the types of CREBBP variants and specific tumor types. Further research is required to clarify the role of CREBBP variants in tumorigenesis.

An unusual presentation of glaucoma in a neonate with Rubinstein-Taybi syndrome

PURPOSE

To report the occurrence of unilateral, neonatal-onset congenital glaucoma in a child with Rubinstein-Taybi Syndrome (RTS).

CASE REPORT

A 15-day-old male with features of RTS was presented with an enlarged corneal diameter, corneal haze, and peripheral corneal vascularization of the left eye. Ultrasound biomicroscopy of his left eye revealed iris atrophy, iridocorneal adhesions, and iris adhesions to a partially absorbed cataractous lens. Genetic evaluation of the child and the parents revealed a novel de novo heterozygous pathogenic variant in exon 5 of the CREBBP gene (NM_004380.3:c.1390C>T). A diode laser cyclophotocoagulation was performed to control the IOP in the left eye.

CONCLUSION

Unilateral neonatal-onset congenital glaucoma due to iridocorneal adhesions can be a rare presentation of Rubinstein-Taybi Syndrome.

A bioinformatics analysis of gene expression in endometrial cancer, endometriosis and obesity

Endometrial cancer (EC), endometriosis (ENDO), and obesity (OBY) are interconnected conditions in women that may share underlying genetic pathways. This study aimed to identify shared genetic pathways and differential gene expressions across these conditions to uncover potential therapeutic targets. A bioinformatics pipeline was applied using gene expression datasets from the GEO database, incorporating differential expression analysis, functional and pathway enrichment, PPI network construction, survival analysis, and mutational profiling across 198 samples. The analysis revealed 26 shared differentially expressed genes (DEGs), with IGF-1, CREBBP, EP300, and PIAS1 identified as key hub genes. Elevated IGF-1 expression was significantly linked to poorer survival outcomes in EC patients (p < .05). Frequent mutations were observed in these hub genes, suggesting their critical role in disease mechanisms. This study highlights genetic links among EC, ENDO, and OBY, emphasizing high IGF-1 expression as a potential prognostic marker in EC and recurrent alterations in hub genes as promising therapeutic targets. These findings provide insights into the shared genetic underpinnings of these conditions and present new avenues for targeted therapies.

Diagnosis and management in Rubinstein-Taybi syndrome: first international consensus statement

Rubinstein-Taybi syndrome (RTS) is an archetypical genetic syndrome that is characterised by intellectual disability, well-defined facial features, distal limb anomalies and atypical growth, among numerous other signs and symptoms. It is caused by variants in either of two genes (CREBBP, EP300) which encode for the proteins CBP and p300, which both have a function in transcription regulation and histone acetylation. As a group of international experts and national support groups dedicated to the syndrome, we realised that marked heterogeneity currently exists in clinical and molecular diagnostic approaches and care practices in various parts of the world. Here, we outline a series of recommendations that document the consensus of a group of international experts on clinical diagnostic criteria for types of RTS (RTS1: CREBBP; RTS2: EP300), molecular investigations, long-term management of various particular physical and behavioural issues and care planning. The recommendations as presented here will need to be evaluated for improvements to allow for continued optimisation of diagnostics and care.

Genotype-phenotype analysis of ocular findings in Rubinstein-Taybi syndrome - A case report and review of literature

BACKGROUND

Rubinstein-Taybi syndrome (RSTS) is a rare genetic syndrome with a wide range of phenotypic presentations, including characteristic facial features. A variety of ocular abnormalities have been described in patients with RSTS. The genetic etiology of RSTS is heterogeneous but often involves two major genes, CREBBP (cAMP-response element binding protein-binding protein) and EP300 (E1A binding protein p300), with CREBBP variants responsible for the majority of the cases.

MATERIALS AND METHODS

We report a new case of female patient with a novel variant in CREBBP (c.4495C>G), with clinical features consistent with RSTS. We performed a literature review to search for possible genotype-phenotype relationships between the type of variant in CREBBP and frequency of ocular presentations. A PubMed search generated 12 articles that met our inclusion criteria. With the addition of our patient, there were a total of 163 patients included for mutation analysis (164 variants given one patient had two different variants).

RESULTS

Our review revealed that the most common variant types were frameshift (25%), gross deletion (23%), nonsense (18%), and intragenic deletions (13%). There does not appear to be an obvious hot spot location. A total of 127 patients were included for genotype-phenotype analysis of ocular features (36 patients were excluded as unable to discern variant type). The most frequent ocular features in patients with RSTS were down-slanting palpebral fissure (74%), arched eyebrows (56%), long eyelashes (52%), and strabismus (23%).

CONCLUSIONS

Our results suggest that currently there is no clear genotype-phenotype relationship between the type of variant and frequency of associated ocular features in RSTS patients.

A novel CREBBP mutation and its phenotype in a case of Rubinstein–Taybi syndrome

Background

This study was to report a novel CREBBP mutation and phenotype in a child with Rubinstein–Taybi syndrome.

Methods

Case report of a 9-year-old boy.

Results

We described the patient’s clinical manifestations in detail, and found that in addition to the typical systemic manifestations of the syndrome, the outstanding manifestation of the child was severe intellectual deficiency and prominent ocular abnormalities. Whole-exome sequencing and sanger sequencing were performed on the patient and his parents, a large intragenic deletion, covering the exon 1 region and part of the intron 1 region of the TRAP1 gene, and the entire region from intron 27 to exon 30 of the CREBBP gene (chr16:3745393-3783894) was identified on the patient. This mutation affected the CREBBP histone acetyltransferase (HAT) domain.

Conclusions

This findings in our patient add to the spectrum of genetic variants described in Rubinstein–Taybi syndrome and present a RSTS patient with various ocular anomalies including early onset glaucoma.

Genetic Diagnosis of Rubinstein–Taybi Syndrome With Multiplex Ligation-Dependent Probe Amplification (MLPA) and Whole-Exome Sequencing (WES): Case Series With a Novel CREBBP Variant

Rubinstein–Taybi Syndrome (RSTS) is a rare congenital disease with distinctive facial features, broadening of the thumbs and halluces, and developmental delay. RSTS is caused by de novo genetic alterations in CREBBP and the homologous EP300 genes. In this study, we established a genetic diagnostic protocol by integrating multiplex ligation-dependent probe amplification (MLPA) and whole-exome sequencing (WES). Five patients clinically diagnosed with RSTS were enrolled for genetic testing. Germline DNA was extracted from the peripheral blood of the patients and their families. One patient (case 1) was identified as harboring a large heterozygous deletion in the 16p13.3 region, spanning the CREBBP gene. Three patients (Cases 2–4) harbored different CREBBP variants (c.2608C>T:p.Gln870Ter,c.4404_4405del:p.Thr1468fs,c.3649C>T:p.Gln1217Ter). No causative variants were identified for the fifth RSTS patient (case 5). Here, we propose a molecular diagnostic protocol that identified causative genetic alterations in 4/5 of the patients, yielding a molecular diagnostic rate of 80%. Given the rarity of RSTS, more research is needed to explore its pathogenesis and mechanism.

Genetic and clinical heterogeneity in Korean patients with Rubinstein-Taybi syndrome

Background

Rubinstein–Taybi syndrome (RSTS) is a rare congenital malformation syndrome with clinical characteristics such as hypertrichosis, high arched eyebrows, large beaked nose, and broad thumbs and halluces. RSTS patients showed intellectual disability and health problems such as short stature, ophthalmologic abnormalities, congenital heart defects, genitourinary defects, and variable types of tumors. Although mutations in CREBBP and EP300 genes are associated with RSTS features, genetic causation is still unknown in 30% of patients.

Methods

We present clinical and molecular genetic characteristics of 25 unrelated Korean patients clinically diagnosed with RSTS. Sanger sequencing analysis and multiplex ligation‐dependent probe amplification for CREBBP in 25 patients and exome sequencing of CREBBP‐negative cases were performed in nine patients successively.

Results

Causative variants were identified in 20 (80%) patients: 16 (64%) in CREBBP and 4 (16%) in EP300. All the identified variants predict protein truncation (11 frameshift, 2 nonsense, 1 splicing‐site, and 6 large intragenic deletions); there are no repeatedly identified sequence variants. Four of the CREBBP and all four EP300 variants are novel. Intellectual disability was noted in 24/25 patients (96%); no difference was found between CREBBP and EP300 groups. One patient with a CREBBP variant (4%) had malignant tumor.

Conclusions

To date, this is the largest cohort of patients with RSTS including EP300‐related patients in Korea. Future large‐scale studies to find genetic mutation of molecularly unsolved patients and long‐term prospective studies are required to validate our results.