Rubinstein-Taybi syndrome with multiple pilomatricomas: The first case diagnosed by CREBBP mutation analysis

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.

Dermatological findings in Rubinstein-Taybi Syndrome

Rubinstein-Taybi Syndrome is a rare congenital multisystem syndrome inherited in an autosomal dominant pattern caused by mutations in CREBBP and EP300 genes in approximately 60% and 10% respectively. These genes encode two highly evolutionarily conserved, ubiquitously expressed, and homologous lysine-acetyltransferases, that are involved in number of basic cellular activities, such as DNA repair, cell proliferation, growth, differentiation, apoptosis of cells, and tumor suppression. It is mainly characterized by global developmental delay, moderate to severe intellectual disability, postnatal retardation, microcephaly, skeletal anomalies including broad/short, angled thumbs and/or large first toes, short stature, and dysmorphic facial features. There is an increased risk to develop tumors mainly meningiomas and pilomatrixomas, without a clear genotype-phenotype correlation. Although not considered as characteristic manifestations, numerous cutaneous anomalies have also been reported in patients with this entity. Both susceptibility to the formation of keloids and pilomatricomas are the most often associated cutaneous features. In this review, we discuss the genetics, diagnosis, and clinical features in Rubinstein-Taybi Syndrome with a review of the major dermatological manifestations.

Cytomorphological spectrum of pilomatricoma - A series of 28 cases

BACKGROUND

Pilomatricoma is a benign tumour that originates in the outer sheath of the hair follicle root. The clinical diagnosis of this rare entity is often missed, possibly due to a lack of awareness. Its characteristic cytomorphological features are sheets of ghost cells, basaloid cells, calcification and foreign body giant cell reaction. However, the above features may not all be present in all cases, rendering cytological diagnosis difficult.

MATERIALS AND METHODS

This retrospective study included all cases of pilomatricoma diagnosed on fine needle aspiration over a period of 4 years. The histopathological diagnosis was retrieved for the cases wherever possible. A detailed histopathological and cytological evaluation was performed for the various components-basaloid cells, ghost cells, calcified debris, foreign body giant cells, bare nuclei, neutrophils, and macrophages-and they were graded on a scale of 0 to 3+.

RESULTS

The 28 cases included 8 female and 20 male patients with a mean age of 34.6 years. Most cases (22 cases; 78.6%) were located in the head and neck, with the scalp being the most common site. Twenty-five cases were cytologically diagnosed as pilomatricoma based on a variable admixture of the various components-nests of basaloid cells, ghost cells, foreign body giant cell reaction, calcified debris and viable squamous cells. However, in two cases which showed an absence of basaloid cells, a differential diagnosis of epidermal inclusion cyst was also included. Another case showed a predominance of basaloid cells with a paucity of ghost cells, so a differential diagnosis of adnexal tumour was also included. Among all the cytological parameters, sheets of ghost cells followed by nests of basaloid cells and foreign body giant cell reaction had the highest sensitivity in the cytological diagnosis of pilomatricoma.

CONCLUSION

The presence of sheets of ghost cells is the most sensitive parameter for the cytological diagnosis of pilomatricoma. It is important that pilomatricoma should be considered in the differential diagnosis of subcutaneous masses, particularly in the head and neck region.

Case report: A preterm infant with rubinstein-taybi syndrome and Marmorata telangiectatica harboring a frameshift mutation in the CREBBP gene

Rubinstein-Taybi syndrome (RSTS) is a rare autosomal dominantly inherited disease characterized by slow mental and physical growth, skeletal abnormalities (broad thumbs and big toes), and dysmorphic facial features. RSTS is associated with de novo variants of the epigenetic-associated gene CREBBP. RSTS is primarily diagnosed based on clinical manifestations and genetic testing. Cutis marmorata telangiectatica congenita (CMTC) is a rare, congenital, and typically benign vascular anomaly of unknown etiology; it is described as persistent reticulated marbled erythema. The diagnosis of CMTC is largely based on clinical features, and GNA11 mutations are associated with CMTC. In this case report, we describe the case of a preterm infant (boy) with RSTS and CMTC who had a novel frameshift mutation leading to a premature stop codon in the CREBBP gene. This study adds the novel mutation c.5837dupC to the known molecular spectrum of disease-causing CREBBP gene mutations.

No Evidence of Abnormal Expression of Beta-Catenin and Bcl-2 Proteins in Pilomatricoma as One Clinical Feature of Tetrasomy 9p Syndrome

Background

Little is currently known about the genetics of pilomatricoma. A number of studies have reported some evidence that this disease may have a genetic association with mutations of CTNNB1 gene or expression of the beta-catenin protein. In this study, we reviewed literatures involving 30 patients with various genetic syndromes that have been linked to pilomatricoma and found that somatic mutations of the CTNNB1 gene were reported in 67% of patients. Pilomatricoma has been reported in patients with chromosome 9 rearrangements, including 4 patients with tetrasomy 9p syndrome and one patient with partial trisomy 9. In addition to beta-catenin, the expression of bcl2 was observed in pilomatricoma.

Objectives

To report an additional case of tetrasomy 9p syndrome with concurrent pilomatricoma and to examine whether abnormal protein expressions of the CTNNB1 and/or BCL2 genes were present.

Methods

Cytogenetic analysis was carried out on peripheral blood, biopsied skin, and pilomatricoma tissue obtained from a patient with tetrasomy 9p syndrome. Immunohistochemical staining was performed on the pilomatricoma tissue, using beta-catenin and bcl2 monoclonal antibodies.

Results

SNP microarray revealed nonmosaic gain of the short arm of chromosome 9. A nonmosaic isodicentric chromosome 9 was identified in the peripheral blood but this rearranged chromosome was detected in only 8.3% of the skin fibroblasts. Chromosomal abnormalities were not detected in the pilomatricoma nor expression of beta-catenin or bcl2 proteins in our patient.

Conclusion

Pilomatricoma could be a new clinical feature associated with tetrasomy 9p syndrome; however, we found no evidence of tetrasomy 9p or abnormal beta-catenin or bcl2 proteins of the CTNNB1 and BCL2 genes in our pilomatricoma patient.

Rubinstein-Taybi Syndrome: A Model of Epigenetic Disorder

The Rubinstein-Taybi syndrome (RSTS) is a rare congenital developmental disorder characterized by a typical facial dysmorphism, distal limb abnormalities, intellectual disability, and many additional phenotypical features. It occurs at between 1/100,000 and 1/125,000 births. Two genes are currently known to cause RSTS, CREBBP and EP300, mutated in around 55% and 8% of clinically diagnosed cases, respectively. To date, 500 pathogenic variants have been reported for the CREBBP gene and 118 for EP300. These two genes encode paralogs acting as lysine acetyltransferase involved in transcriptional regulation and chromatin remodeling with a key role in neuronal plasticity and cognition. Because of the clinical heterogeneity of this syndrome ranging from the typical clinical diagnosis to features overlapping with other Mendelian disorders of the epigenetic machinery, phenotype/genotype correlations remain difficult to establish. In this context, the deciphering of the patho-physiological process underlying these diseases and the definition of a specific episignature will likely improve the diagnostic efficiency but also open novel therapeutic perspectives. This review summarizes the current clinical and molecular knowledge and highlights the epigenetic regulation of RSTS as a model of chromatinopathy.

Multiple pilomatricomas in twins with Rubinstein-Taybi syndrome

Pilomatricomas are benign tumors originating from the capillary matrix, which may present as solitary lesions or, less commonly, multiple. Myotonic dystrophy and familial adenomatous polyposis are the most frequently associated disorders with multiple pilomatricomas. There are few reports relating these tumors to other genetic syndromes. Rubinstein-Taybi syndrome is a rare autosomal dominant disorder characterized by intellectual disability and typical dysmorphic characteristics. There are five case reports relating to multiple pilomatricoma to Rubinstein-Taybi syndrome, an association that needs to be clarified. For this reason, we report the first case of multiple pilomatricoma in monozygotic twins with typical Rubinstein-Taybi syndrome.

Clinical exome sequencing identifies novel CREBBP variants in 18 Chinese Rubinstein-Taybi Syndrome kids with high frequency of polydactyly

Background

Rubinstein–Taybi syndrome (RSTS) is a rare genetic disease characterized by broad thumbs and halluces, facial dysmorphisms, short stature, and intellectual disability. RSTS is mainly caused by de novo variants in epigenetics‐associated gene, CREBBP. To date, there is no cohort study of CREBBP variants in Chinese RSTS patients.

Methods

In this study, 18 kids who meet the main criteria of RSTS were recruited. Molecular diagnoses were analyzed by clinical exome sequencing (CES), and the medical records were reviewed retrospectively.

Results

Nineteen novel CREBBP variants in 18 RSTS patients were identified, including two missense, four nonsense, five frameshift, one splicing variants, and seven intragenic deletions. A higher incidence (37%, 7/19) of intragenic deletions was detected. One patient who had two de novo missense variants c.[4112T > A, 4118C > A] in cis and one patient who had a de novo frameshift variant c.5837delC in homozygous state (90%) were found in this study. Compared with the previously reported populations, seven clinical features were different, including the higher incidence of polydactyly, syndactyly, microcephaly, and micrognathia, and the lower incidence of angulated thumbs, autistic behavior, and epilepsy. One patient with obesity in the first year was diagnosed with CREBBP gene exon 2 deletion, was initially suspected of Prader–Willi syndrome.

Conclusion

We reported the genetic and clinical information of 18 RSTS patients from Chinese population with novel CREBBP variants. This study provides a new insight into RSTS and illustrates the value of applying CES which increases the diagnostic yields and enhances the clinical care of RSTS patients.

Multiple Pilomatricomas: A Retrospective Study and Literature Review

Pilomatricoma is usually a single lesion. However, some patients present with more than one, a fact that has been reported in association with several systemic diseases. The aim of this analysis is to determine the prevalence of multiple pilomatricomas (MP) in our institution as well as to describe their clinical features and associated comorbidities. This is a retrospective analysis reviewing patients with a histological diagnosis of pilomatricoma registered in the database of the Pathology Department of our institution, from January 2005 to March 2017. One hundred ninety-five patients with histological criteria for pilomatricoma were registered. Fourteen (0.7%) of those patients suffered from MP. Among them, the most relevant findings were: 9 (64%) patients were women and 5 (36%) were men. The median age at diagnosis was 16 years. Seven (50%) had 2 pilomatricomas and 7 (50%) had more than 2. Two (14%) suffered from Steinert myotonic dystrophy (SMD). Regarding family background, 3 of them had relatives with pilomatricomas, one of them with pancreatic cancer, and another one with SMD. A total of 36 pilomatricomas were excised from those 14 patients with the following characteristics: The mean lesion size was 12 mm. The majority of the lesions (53%) were located on the head and neck. There was no recurrence or malignant transformation in any patient. Articles reporting on MP are scarce. We communicate 2 new familial MP without associated comorbidities. We would like to highlight that 2 of our patients with MP also developed SMD, an association previously reported. Thus, a thorough physical examination and inquiring about family history are of utmost importance for an early diagnosis of possible associated diseases.

Benign and malignant tumors in Rubinstein-Taybi syndrome

Rubinstein–Taybi syndrome (RSTS) is a multiple congenital anomalies syndrome associated with mutations in CREBBP (70%) and EP300 (5–10%). Previous reports have suggested an increased incidence of specific benign and possibly also malignant tumors. We identified all known individuals diagnosed with RSTS in the Netherlands until 2015 (n = 87) and studied the incidence and character of neoplastic tumors in relation to their CREBBP/EP300 alterations. The population–based Dutch RSTS data are compared to similar data of the Dutch general population and to an overview of case reports and series of all RSTS individuals with tumors reported in the literature to date. Using the Nationwide Network and Registry of Histopathology and Cytopathology in the Netherlands (PALGA Foundation), 35 benign and malignant tumors were observed in 26/87 individuals. Meningiomas and pilomatricomas were the most frequent benign tumors and their incidence was significantly elevated in comparison to the general Dutch population. Five malignant tumors were observed in four persons with RSTS (medulloblastoma; diffuse large‐cell B‐cell lymphoma; breast cancer; non‐small cell lung carcinoma; colon carcinoma). No clear genotype–phenotype correlation became evident. The Dutch population‐based data and reported case studies underscore the increased incidence of meningiomas and pilomatricomas in individuals with RSTS. There is no supporting evidence for an increased risk for malignant tumors in individuals with RSTS, however, due to the small numbers this risk may not be fully dismissed.