Genotypic and phenotypic spectrum in tricho-rhino-phalangeal syndrome types I and III

Clinical presentation and genetics of tricho-rhino-phalangeal syndrome (TRPS) type 1: A single-center case series of 15 patients and seven novel TRPS1 variants

Tricho-rhino-phalangeal syndrome (TRPS) is a rare malformation syndrome characterized by distinctive facial, ectodermal, and skeletal features. TRPS is divided into TRPS type I/III caused by pathogenic variants in TRPS1 and TRPS type II caused by contiguous gene deletions also spanning EXT1 and RAD21. Due to its rarity, knowledge of the clinical course of TRPS remains limited. Therefore, we collected and characterized a case series of 15 TRPS type I patients (median age at diagnosis 15 [interquartile range: 10-18] years, 11 females [73%]) seen at Aarhus University Hospital, Denmark, with a median follow-up period of 10 years. We estimated a minimum point prevalence of 0.5 in 100,000 (95% CI: 0.3-0.8 per 100,000) persons. Common craniofacial features included fine and sparse hair with a high anterior hairline, eyebrows with lateral thinning and a thicker medial part, prominent ears, a bulbous nose tip with small nasal alae, a low-hanging, and often wide columella, and a long philtrum with a thin upper vermillion. Specific skeletal features included short stature and deviating and short fingers with cone-shaped epiphyses and shortened metacarpals on radiographs. The most significant morbidity of the cohort was joint complaints, which were reported by all patients, often already before the TRPS diagnosis was established. We identified ten different TRPS1 variants including both frameshift/nonsense, missense, and splice-site variants, including seven variants not previously reported in the literature. In accordance with previous literature, no genotype-phenotype correlation was identified. The clinical trajectories were heterogeneous involving pediatrics, dermatology, orthopedic surgery, clinical genetics, and/or odontology, emphasizing that close multidisciplinary collaboration is essential for early diagnosis of TRPS and to ensure proper and timely patient care and counseling.

Successful topical minoxidil treatment for hair density and length in trichorhinophalangeal syndrome type 1

A 9-year-old girl presented with slow hair growth and hair thinning since birth. Additionally, she had short stature and abnormally short fingers; genetic testing confirmed the diagnosis of trichorhinophalangeal syndrome (TRPS) type 1. After 4 months of topical minoxidil treatment, hair density and length significantly improved diffusely throughout the scalp without evidence of hypertrichosis. This case underscores the therapeutic potential of topical minoxidil for TRPS, paving the way for improved patient quality of life.

TRPS1 expression in non-melanocytic cutaneous neoplasms: an immunohistochemical analysis of 200 cases

BACKGROUND

Although trichorhinophalangeal syndrome type 1 (TRPS1) was initially thought to be highly sensitive and specific for carcinomas and mesenchymal tumors of mammary origin, more recent data suggest its expression is not limited to breast neoplasms but also can be seen in other cutaneous neoplasms, such as extramammary Paget disease and squamous cell carcinoma (SCC) in situ.

METHODS

Two-hundred cases of non-melanocytic cutaneous neoplasm, including basal cell carcinomas (BCCs) (n = 41), SCCs (n = 35), Merkel cell carcinomas (MCCs) (n = 25), and adnexal neoplasms (n = 99), were tested for TRPS1 expression using a monoclonal anti- TRPS1 rabbit anti-human antibody.

RESULTS

TRPS1 expression was present in almost all cases of SCC (94%), with a median H-score of 200, while it was either absent or only focally present in most BCCs (90%), with a median H-score of 5. The difference between BCCs and SCCs in H-score was significant (p < .001). All MCCs (100%) lacked TRPS1 expression. TRPS1 expression was frequently seen in most adnexal neoplasms, benign and malignant, in variable intensity and proportion but was consistently absent in apocrine carcinomas. All endocrine mucin-producing sweat gland carcinomas (EMPSGCs) (100%, 6/6) showed diffuse and strong TRPS1 immunoreactivity, with a median H-score of 300, which was significantly different (p < .001) than that of BCCs.

CONCLUSIONS

Our study shows that TRPS1 may be an effective discriminatory marker for BCCs and SCCs. It also has a role in distinguishing BCCs from EMPSGCs.

Cis-regulatory control of mammalian Trps1 gene expression

TRPS1 serves as the causative gene for tricho-rhino phalangeal syndrome, known for its craniofacial and skeletal abnormalities. The Trps1 gene encodes a protein that represses Wnt signaling through strong interactions with Wnt signaling inhibitors. The identification of genomic cis-acting regulatory sequences governing Trps1 expression is crucial for understanding its role in embryogenesis. Nevertheless, to date, no investigations have been conducted concerning these aspects of Trps1. To identify deeply conserved noncoding elements (CNEs) within the Trps1 locus, we employed a comparative genomics approach, utilizing slowly evolving fish such as coelacanth and spotted gar. These analyses resulted in the identification of eight CNEs in the intronic region of the Trps1 gene. Functional characterization of these CNEs in zebrafish revealed their regulatory potential in various tissues, including pectoral fins, heart, and pharyngeal arches. RNA in-situ hybridization experiments revealed concordance between the reporter expression pattern induced by the identified set of CNEs and the spatial expression pattern of the trps1 gene in zebrafish. Comparative in vivo data from zebrafish and mice for CNE7/hs919 revealed conserved functions of these enhancers. Each of these eight CNEs was further investigated in cell line-based reporter assays, revealing their repressive potential. Taken together, in vivo and in vitro assays suggest a context-dependent dual functionality for the identified set of Trps1-associated CNE enhancers. This functionally characterized set of CNE-enhancers will contribute to a more comprehensive understanding of the developmental roles of Trps1 and can aid in the identification of noncoding DNA variants associated with human diseases.

Comparative expression of TRPS1, GATA3, SOX10, mammaglobin, and GCDFP-15 in effusion specimens with breast carcinoma

BACKGROUND

Traditional immunohistochemistry (IHC) for breast carcinomas has shown low detection rates of metastatic breast carcinoma (MBC) in effusions. Although GATA3 has enhanced diagnostic accuracy in this realm, its limited utility in detecting triple-negative breast carcinoma (TNBC) has been highlighted. TRPS1 has been introduced as a potentially sensitive and specific marker in detecting MBC on histologic samples. We investigate the utility of TRPS1 as a marker for MBC in effusion specimens and compare its performance to SOX10, GATA3, mammaglobin (MG), and GCDFP-15.

METHODS

A database search identified malignant effusions involved by MBC between 2013 and 2021. Cases from unique patients with sufficient cellularity were evaluated for TRPS1, GATA3, SOX10, MG, and GCDFP-15 IHC. The intensity and extent of tumor cells (TC) were scored by two pathologists. Any discrepancies were jointly reviewed for consensus.

RESULTS

GATA3 showed the highest rate of positivity (98.2%), followed by TRPS1 (89.5%), MG (43.9%), GCDFP-15 (21.1%), and SOX10 (3.5%). All GATA3-positive cases showed intermediate to high expression. Comparatively, TRPS1 showed more variability in staining extent and intensity. In 13 (22.8%) cases, TRPS1 showed extensive background staining of inflammatory and mesothelial cells. Of six TNBCs, GATA3, and TRPS1 were positive in six (100%) and four (66.7%) cases, respectively.

CONCLUSIONS

While TRPS1 shows a lower detection rate for MBC than GATA-3, using a combination of these markers can enhance effusion cytology's performance in detecting MBC. However, variability in TRPS1 staining intensity and high background TRPS1 staining of inflammatory and mesothelial cells can increase difficulty in its evaluation.

Utility of TRPS1 immunohistochemistry in confirming breast carcinoma: Emphasis on staining in triple-negative breast cancers and gynecologic tumors

OBJECTIVES

Our aim was to explore the performance of TRPS1 as an immunohistochemical diagnostic marker; find the optimal conditions for its use in breast carcinomas, especially triple-negative breast cancers (TNBCs); and compare its results in carcinomas of a select few organ sites, with an emphasis on gynecologic tumors.

METHODS

Tissue microarrays from breast carcinomas (n = 197), endometrial adenocarcinomas (n = 69), ovarian tumors (n = 250), vulvar squamous cell carcinomas (n = 97), pancreatic ductal adenocarcinomas (n = 20), and gastric adenocarcinomas (n = 12) were stained with TRPS1 using 2 different conditions (protocol 1: high pH; protocol 2: low pH). Breast carcinomas consisted of hormone receptor (HR)-positive/ERBB2 (formerly HER2 or HER2/neu)-negative (n = 53) samples, HR-positive/ERBB2-positive (n = 6) samples, and TNBCs (n = 138).

RESULTS

Comparing TRPS1 results in breast carcinomas vs tumors from other organ sites, the sensitivity of TRPS1 was 91% and 87%, respectively, while the specificity was 66% and 74% for protocol 1 and 2, respectively. For TNBCs vs gynecologic tumors, the sensitivity of TRPS1 was 89% and 85%, respectively, while the specificity was 65% and 73%, respectively.

CONCLUSIONS

TRPS1 stains approximately 90% of breast carcinomas but also up to 71% of endometrial carcinomas, albeit with a weaker median expression. Our data show that although TRPS1 is a highly sensitive marker for TNBCs, it is not as highly specific as previously reported.

Late Presentation of Tricho-Rhino-Phalangeal Syndrome (TRPS1 Affected) Associated Hip Pathology

Perthes disease typically presents between the ages of 4 and 9 years and is characterized by unilateral or bilateral avascular necrosis of the femoral head. Clinically it presents with pain and decreased range of motion and has a disease course of up to 5 years. We report the clinical and radiological findings of a female in early adolescence who was referred to pediatric physiotherapy and found to have Perthes-like changes of the hip, on a background of tricho-rhino-phalangeal syndrome type 1 (TRPS1). The patient's first symptoms of hip pain were reported at age 10, but there was no radiographic evidence until 2.5 years later when a diagnosis of Perthe's disease was made. This uniquely late presentation may have been due to the altered skeletal maturation seen in TRPS1, whereby skeletal age lags behind chronological age. This case highlights the importance of identifying relevant past medical history on initial assessment, and having rapid access to radiology and orthopedic support to enable timely diagnosis, as prognosis becomes poorer as age increases. Perthes-like changes should be considered as a differential diagnosis in patients presenting with non-traumatic hip pain, regardless of age of onset.

Systematic elucidation and pharmacological targeting of tumor-infiltrating regulatory T cell master regulators

Due to their immunosuppressive role, tumor-infiltrating regulatory T cells (TI-Tregs) represent attractive immuno-oncology targets. Analysis of TI vs. peripheral Tregs (P-Tregs) from 36 patients, across four malignancies, identified 17 candidate master regulators (MRs) as mechanistic determinants of TI-Treg transcriptional state. Pooled CRISPR-Cas9 screening in vivo, using a chimeric hematopoietic stem cell transplant model, confirmed the essentiality of eight MRs in TI-Treg recruitment and/or retention without affecting other T cell subtypes, and targeting one of the most significant MRs (Trps1) by CRISPR KO significantly reduced ectopic tumor growth. Analysis of drugs capable of inverting TI-Treg MR activity identified low-dose gemcitabine as the top prediction. Indeed, gemcitabine treatment inhibited tumor growth in immunocompetent but not immunocompromised allografts, increased anti-PD-1 efficacy, and depleted MR-expressing TI-Tregs in vivo. This study provides key insight into Treg signaling, specifically in the context of cancer, and a generalizable strategy to systematically elucidate and target MR proteins in immunosuppressive subpopulations.

Molecular Genetic Analysis and Growth Hormone Treatment in a Three-Generation Chinese Family with Tricho-Rhino-Phalangeal Syndrome I

INTRODUCTION

Tricho-rhino-phalangeal syndrome (TRPS) is a rare genetic disorder characterized by craniofacial and skeletal abnormalities, which is caused by variants in the TRPS1 gene.

METHODS

Clinical information and follow-up data were collected. Whole-exome sequencing (WES) was performed for variants and validated by Sanger sequencing. Bioinformatic analysis was performed to predict the pathogenicity of the identified variant. Moreover, wild-type and mutated TRPS1 vectors were constructed and transfected into human embryonic kidney (HEK) 293T cells. Immunofluorescence experiments were performed to assess the localization and expression of the mutated protein. Western blot analysis and RT-qPCR were used to detect the expression of downstream genes.

RESULTS

The affected family members had typical craniofacial phenotype including sparse lateral eyebrows, pear-shaped nasal tip, and large prominent ears, plus skeletal abnormalities including short stature and brachydactyly. WES and Sanger sequencing identified the TRPS1 c.880_882delAAG variant in affected family members. In vitro functional studies showed that the TRPS1 variant did not affect the cellular localization and the expression of TRPS1, but the transcriptional repression effect of the TRPS1 on the RUNX2 and STAT3 was disturbed. The proband and his brother have been treated with growth hormone (GH) for 2 years until now, and we have observed the improvement of the linear growth in both.

CONCLUSIONS

The variant of c.880_882delAAG in TRPS1 was responsible for the pathogenesis of the Chinese family with TRPS I. The treatment of GH could be beneficial for the height outcome in TRPS I patients, and earlier initiation and longer duration of the therapy in prepubertal or early pubertal stage could be associated with better height outcomes.

The Clinical and Molecular Spectrum of Trichorhinophalangeal Syndrome Types I and II in a Turkish Cohort Involving 22 Patients

OBJECTIVE

Trichorhinophalangeal syndrome is a rare autosomal dominant disorder characterized by distinctive craniofacial and skeletal abnormalities. This study aimed to delineate the trichorhinophalangeal syndrome phenotype and to compare the clinical and molecular findings between trichorhinophalangeal syndrome types I and II.

MATERIALS AND METHODS

A total of 22 trichorhinophalangeal syndrome patients aged 0.9-45 years from 17 families were enrolled. Nineteen patients were diagnosed with trichorhin ophalangeal syndrome I and 3 with trichorhinophalangeal syndrome II. Genetic analyses were made by TRPS1 sequencing and/or chromosomal microarray analyses.

RESULTS

A novel frameshift variant (c.531_532del), a known missense variant, and whole-gene deletions were the pathogenic TRPS1 variants detected in trichorhinophalangeal syndrome I. Three trichorhinophalangeal syndrome II patients had large deletions with variable breakpoints involving the TRPS1-EXT1 interval. All patients had the typical craniofacial findings of trichorhinophalangeal syndrome such as a pear-shaped nose, long philtrum, and thin upper lip, as well as cone-shaped epiphyses. Sparse hair and eyebrows (20/22), short metacarpals and metatarsals (20/22), and small hands (19/22) were common. While craniofacial and limb abnormalities were similar in trichorhinophalangeal syndrome I and II, 3 of 19 trichorhinophal angeal syndrome I patients had mild, and 2 of 3 trichorhinophalangeal syndrome II patients had severe intellectual disability. Three trichorhinophalangeal syndrome II patients including the patient with the EXT1 deletion beginning from exon 2 had exostoses. In trichorhinophal angeal syndrome II, although microdeletion sizes and facial or skeletal features were not correlated, patients with larger deletions had severe intellectual disability.

CONCLUSION

This study has expanded the existing knowledge on the phenotype-genotype spectrum in trichorhinophalangeal syndrome. We suggest including the EXT1 gene partially in the minimal critical region for trichorhinophalangeal syndrome II.

Trichorhinophalangeal Syndrome Type 1-Positive Cells in Breast Dermal Granulation Tissues and Scars: A Potential Diagnostic Pitfall

ABSTRACT

Trichorhinophalangeal syndrome type 1 (TRPS1) immunohistochemistry has been gaining popularity in recent years in the field of surgical pathology for its utility as a highly sensitive and specific marker for breast carcinomas, including those with triple-negative phenotype. More recent data suggest TRPS1 may also prove its utility in the diagnosis of mesenchymal tumors arising in the breast parenchyma, including malignant phyllodes tumors and primary chondrosarcomas and osteosarcomas of the breast. However, little is known about TRPS1 expression in nontumor cells, such as stromal fibroblasts/myofibroblasts of dermal granulation tissues and scars. Here, we describe our unique experience with TRPS1-positive cells, morphologically consistent with reactive fibroblasts/myofibroblasts, seen in dermal granulation tissues and scars from breast skin specimens of a 51-year-old woman with a history of bilateral invasive ductal carcinomas of the breast, status after bilateral total mastectomy and chemoradiation, who presented with nonhealing wounds on the chests. To the best of our knowledge, this is the first reported case of strong TRPS1 expression in dermal granulation tissue/scar. As the usage of TRPS1 immunohistochemistry in routine clinical practice, including in the field of dermatopathology, will likely increase over time, awareness of this potential diagnostic pitfall is important to avoid overinterpretation of the findings.

Characterization of a Novel Frameshift Mutation Within the TRPS1 Gene Causing Trichorhinophalangeal Syndrome Type 1 in a Kindred Cypriot Family

Trichorhinophalangeal syndrome (TRPS) is an extremely rare autosomal dominant multisystem disorder characterized by craniofacial and skeletal abnormalities. Three subtypes of TRPS have been described: TRPS type I, TRPS type II, and TRPS type III. Mutations in the TRPS1 gene can cause both TRPS type I and TRPS type III. Therefore, the genotype-phenotype correlation is crucial to determine the subtype. The current family study from Cyprus involves affected patients from 4 generations who presented with alopecia, unoperated umbilical hernia, caput quadratum, long philtrum, depressed nasal bridge, frontal bossing, pes planus, beaked nose, and some deformities in hands and feet. Sequence analysis of the TRPS1 gene revealed a novel c.2854_2858del (p.Asn952ArgfsTer2) frameshift variant leading to a premature stop codon. To the best of our knowledge, we report here the first case of a Turkish Cypriot family of 4 generations with a novel frameshift mutation leading to truncated protein in the TRPS1 gene causing TRPS type I clinical phenotype. Overall, as the genotype and phenotype correlation in TRPSI is still uncertain and complex, the present outcome can enhance our knowledge of this complicated, rare, and severe genetic disorder.

Functional mechanisms of TRPS1 in disease progression and its potential role in personalized medicine

The gene of transcriptional repressor GATA binding 1 (TRPS1), as an atypical GATA transcription factor, has received considerable attention in a plethora of physiological and pathological processes, and may become a promising biomarker for targeted therapies in diseases and tumors. However, there still lacks a comprehensive exploration of its functions and promising clinical applications. Herein, relevant researches published in English from 2000 to 2022 were retrieved from PubMed, Google Scholar and MEDLINE, concerning the roles of TRPS1 in organ differentiation and tumorigenesis. This systematic review predominantly focused on summarizing the structural characteristics and biological mechanisms of TRPS1, its involvement in tricho-rhino-phalangeal syndrome (TRPS), its participation in the development of multiple tissues, the recent advances of its vital features in metabolic disorders as well as malignant tumors, in order to prospect its potential applications in disease detection and cancer targeted therapy. From the clinical perspective, the deeply and thoroughly understanding of the complicated context-dependent and cell-lineage-specific mechanisms of TRPS1 would not only gain novel insights into the complex etiology of diseases, but also provide the fundamental basis for the development of therapeutic drugs targeting both TRPS1 and its critical cofactors, which would facilitate individualized treatment.

Deficiency of Mineralization-Regulating Transcription Factor Trps1 Compromises Quality of Dental Tissues and Increases Susceptibility to Dental Caries

Dental caries is the most common chronic disease in children and adults worldwide. The complex etiology of dental caries includes environmental factors as well as host genetics, which together contribute to inter-individual variation in susceptibility. The goal of this study was to provide insights into the molecular pathology underlying increased predisposition to dental caries in trichorhinophalangeal syndrome (TRPS). This rare inherited skeletal dysplasia is caused by mutations in the TRPS1 gene coding for the TRPS1 transcription factor. Considering Trps1 expression in odontoblasts, where Trps1 supports expression of multiple mineralization-related genes, we focused on determining the consequences of odontoblast-specific Trps1 deficiency on the quality of dental tissues. We generated a conditional Trps1Col1a1 knockout mouse, in which Trps1 is deleted in differentiated odontoblasts using 2.3kbCol1a1-CreERT2 driver. Mandibular first molars of 4wk old male and female mice were analyzed by micro-computed tomography (μCT) and histology. Mechanical properties of dentin and enamel were analyzed by Vickers microhardness test. The susceptibility to acid demineralization was compared between WT and Trps1Col1a1cKO molars using an ex vivo artificial caries procedure. μCT analyses demonstrated that odontoblast-specific deletion of Trps1 results in decreased dentin volume in male and female mice, while no significant differences were detected in dentin mineral density. However, histology revealed a wider predentin layer and the presence of globular dentin, which are indicative of disturbed mineralization. The secondary effect on enamel was also detected, with both dentin and enamel of Trps1Col1a1cKO mice being more susceptible to demineralization than WT tissues. The quality of dental tissues was particularly impaired in molar pits, which are sites highly susceptible to dental caries in human teeth. Interestingly, Trps1Col1a1cKO males demonstrated a stronger phenotype than females, which calls for attention to genetically-driven sex differences in predisposition to dental caries. In conclusion, the analyses of Trps1Col1a1cKO mice suggest that compromised quality of dental tissues contributes to the high prevalence of dental caries in TRPS patients. Furthermore, our results suggest that TRPS patients will benefit particularly from improved dental caries prevention strategies tailored for individuals genetically predisposed due to developmental defects in tooth mineralization.

Novel Pathogenetic Variants in PTHLH and TRPS1 Genes Causing Syndromic Brachydactyly

Skeletal disorders, including both isolated and syndromic brachydactyly type E, derive from genetic defects affecting the fine tuning of the network of pathways involved in skeletogenesis and growth-plate development. Alterations of different genes of this network may result in overlapping phenotypes, as exemplified by disorders due to the impairment of the parathyroid hormone/parathyroid hormone-related protein pathway, and obtaining a correct diagnosis is sometimes challenging without a genetic confirmation. Five patients with Albright's hereditary osteodystrophy (AHO)-like skeletal malformations without a clear clinical diagnosis were analyzed by whole-exome sequencing (WES) and novel potentially pathogenic variants in parathyroid hormone like hormone (PTHLH) (BDE with short stature [BDE2]) and TRPS1 (tricho-rhino-phalangeal syndrome [TRPS]) were discovered. The pathogenic impact of these variants was confirmed by in vitro functional studies. This study expands the spectrum of genetic defects associated with BDE2 and TRPS and demonstrates the pathogenicity of TRPS1 missense variants located outside both the nuclear localization signal and the GATA ((A/T)GATA(A/G)-binding zinc-containing domain) and Ikaros-like binding domains. Unfortunately, we could not find distinctive phenotypic features that might have led to an earlier clinical diagnosis, further highlighting the high degree of overlap among skeletal syndromes associated with brachydactyly and AHO-like features, and the need for a close interdisciplinary workout in these rare patients. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Case report: A novel mutation in TRPS1 identified in a Chinese family with tricho-rhino-phalangeal syndrome I: A therapeutic challenge

Tricho-rhino-phalangeal syndrome (TRPS) is a rare autosomal dominant malformation caused by mutations involving the TRPS1 gene. Patients with TRPS exhibit distinctive craniofacial and skeletal abnormalities. This report presents three intra-familial cases with TRPS1 gene mutations that showed the characteristic features of TRPS. A 13-year-old boy was admitted to Department of Endocrinology for the evaluation of short stature. Physical examination revealed that the boy had thin sparse hair, pear-shaped nose, protruding ears, small jaw and brachydactyly. A survey of his family history indicated that the boy's sister and mother shared the same clinical features. Radiological techniques demonstrated a different degree of skeletal abnormalities in these siblings. Next-generation sequencing and quantitative PCR were performed and showed a novel deletion mutation in exons 3-5 in the three familial cases, confirming the diagnosis of TRPS I. The healthy father did not carry the deletion mutation. Currently, there was no specific therapy for TRPS I; however, genetic consultation may be useful for family planning.

Molecular genetic analysis and growth hormone response in patients with syndromic short stature

BACKGROUND

Syndromic short stature is a genetic and phenotypic heterogeneous disorder with multiple causes. This study aims to identify genetic causes in patients with syndromic short stature of unknown cause and evaluate the efficacy of the growth hormone response.

METHODS

Trio-whole-exome sequencing was applied to identify pathogenic gene mutations in seven patents with short stature, multiple malformations, and/or intellectual disability. Whole-genome low-coverage sequencing was also performed to identify copy number variants in three patients with concurrent intellectual disability. Recombinant human growth hormone was administered to improve height in patients with an identified cause of syndromic short stature.

RESULTS

Of the seven patients, three pathogenic/likely pathogenic gene mutations, including one FGFR3 mutation (c.1620C>A p.N540K), one novel GNAS mutation (c.2288C>T p.A763V), and one novel TRPS1 mutation (c.2527_c.2528dupTA p.S843fsX72), were identified in three patients. No copy number variants were identified in the three patients with concurrent intellectual disability. The proband with an FGFR3 mutation, a female 4 and 3/12 years of age, was diagnosed with hypochondroplasia. Long-acting growth hormone improved her height from 85.8 cm [- 5.05 standard deviation (SD)] to 100.4 cm (- 4.02 SD), and her increased height SD score (SDS) was 1.03 after 25 months of treatment. The proband with a GNAS mutation, a female 12 and 9/12 years of age, was diagnosed with pseudohypoparathyroidism Ia. After 14 months of treatment with short-acting growth hormone, her height improved from 139.3 cm (- 2.69 SD) to 145.0 cm (- 2.36 SD), and her increased height SDS was 0.33.

CONCLUSIONS

Trio-whole-exome sequencing was an important approach to confirm genetic disorders in patients with syndromic short stature of unknown etiology. Short-term growth hormone was effective in improving height in patients with hypochondroplasia and pseudohypoparathyroidism Ia.

Update of recent findings in genetic hair disorders

Genetic hair disorders, although unusual, are not very rare, and dermatologists often have opportunities to see patients. Significant advances in molecular genetics have led to identifying many causative genes for genetic hair disorders, including the recently identified causative genes, such as LSS and C3ORF52. Many patients have been detected with autosomal recessive woolly hair/hypotrichosis in the Japanese population caused by founder mutations in the LIPH gene. Additionally, many patients with genetic hair disorders caused by other genes have been reported in East Asia including Japan. Understanding genetic hair disorders is essential for dermatologists, and the findings obtained from analyzing these diseases will contribute to revealing the mechanisms of hair follicle morphogenesis and development in humans.

TRPS1 drives heterochromatic origin refiring and cancer genome evolution

Exploitation of naturally occurring genetic mutations could empower the discovery of novel aspects of established cancer genes. We report here that TRPS1, a gene linked to the tricho-rhino-phalangeal syndrome (TRPS) and recently identified as a potential breast cancer driver, promotes breast carcinogenesis through regulating replication. Epigenomic decomposition of TRPS1 landscape reveals nearly half of H3K9me3-marked heterochromatic origins are occupied by TRPS1, where it encourages the chromatin loading of APC/C, resulting in uncontrolled origin refiring. TRPS1 binds to the genome through its atypical H3K9me3 reading via GATA and IKAROS domains, while TRPS-related mutations affect its chromatin binding, replication boosting, and tumorigenicity. Concordantly, overexpression of wild-type but not TRPS-associated mutants of TRPS1 is sufficient to drive cancer genome amplifications, which experience an extrachromosomal route and dynamically evolve to confer therapeutic resistance. Together, these results uncover a critical function of TRPS1 in driving heterochromatin origin firing and breast cancer genome evolution.

Cardiac arrest in a patient with trichorhinophalangeal syndrome and dilated cardiomyopathy

A 44-year-old woman with known trichorhinophalangeal syndrome presented with an unheralded out of hospital cardiac arrest. Transthoracic echocardiography showed severe left ventricular systolic dysfunction with an ejection fraction <25% and cardiac MRI confirmed a diagnosis of congenital non-ischaemic dilated cardiomyopathy. The case highlights a very rare syndrome, it is previously unknown association with dilated cardiomyopathy and the possible benefit of cardiac screening for patients with known trichorhinophalangeal syndrome.

Bone fragility in patients affected by congenital diseases non skeletal in origin

BACKGROUND

Bone tissue represents a large systemic compartment of the human body, with an active metabolism, that controls mineral deposition and removal, and where several factors may play a role. For these reasons, several non-skeletal diseases may influence bone metabolism. It is of a crucial importance to classify these disorders in order to facilitate diagnosis and clinical management. This article reports a taxonomic classification of non-skeletal rare congenital disorders, which have an impact on bone metabolism METHODS: The International Osteoporosis Foundation (IOF) Skeletal Rare Diseases Working Group (SRD-WG), comprised of basic and clinical scientists, has decided to review the taxonomy of non-skeletal rare disorders that may alter bone physiology.

RESULTS

The taxonomy of non-skeletal rare congenital disorders which impact bone comprises a total of 6 groups of disorders that may influence the activity of bone cells or the characteristics of bone matrix.

CONCLUSIONS

This paper provides the first comprehensive taxonomy of non-skeletal rare congenital disorders with impact on bone physiology.

Trps1 transcription factor represses phosphate-induced expression of SerpinB2 in osteogenic cells

Serine protease inhibitor SerpinB2 is one of the most upregulated proteins following cellular stress. This multifunctional serpin has been attributed a number of pleiotropic activities, including roles in cell survival, proliferation, differentiation, immunity and extracellular matrix (ECM) remodeling. Studies of cancer cells demonstrated that expression of SerpinB2 is directly repressed by the Trps1 transcription factor, which is a regulator of skeletal and dental tissues mineralization. In our previous studies, we identified SerpinB2 as one of the novel genes highly upregulated by phosphate (P_i) at the initiation of the mineralization process, however SerpinB2 has never been implicated in formation nor homeostasis of mineralized tissues. The aim of this study was to establish, if SerpinB2 is involved in function of cells producing mineralized ECM and to determine the interplay between P_i signaling and Trps1 in the regulation of SerpinB2 expression specifically in cells producing mineralized ECM. Analyses of the SerpinB2 expression pattern in mouse skeletal and dental tissues detected high SerpinB2 protein levels specifically in cells producing mineralized ECM. qRT-PCR and Western blot analyses demonstrated that SerpinB2 expression is activated by elevated P_i specifically in osteogenic cells. However, the P_i-induced SerpinB2 expression was diminished by overexpression of Trps1. Decreased SerpinB2 levels were also detected in osteoblasts and odontoblasts of 2.3Col1a1-Trps1 transgenic mice. Chromatin immunoprecipitation assay (ChIP) revealed that the occupancy of Trps1 on regulatory elements in the SerpinB2 gene changes in response to P_i. In vitro functional assessment of the consequences of SerpinB2 deficiency in cells producing mineralized ECM detected impaired mineralization in SerpinB2-deficient cells in comparison with controls. In conclusion, high and specific expression of SerpinB2 in cells producing mineralized ECM, the impaired mineralization of SerpinB2-deficient cells and regulation of SerpinB2 expression by two molecules regulating formation of mineralized tissues suggest involvement of SerpinB2 in physiological mineralization.

Assessment of longitudinal bone growth in osteogenesis imperfecta using metacarpophalangeal pattern profiles

OBJECTIVE

Osteogenesis imperfecta (OI) is commonly associated with short stature, but it is unclear whether this is exclusively secondary to fractures and bone deformities or whether there is a primary defect in longitudinal bone growth. As metacarpal and phalangeal bones are rarely affected by fractures and deformities, any length deficits in these bones should reflect a direct disease effect on longitudinal growth. This study therefore assessed the relationship of hand bone length with clinical OI type and genotype.

STUDY DESIGN

Prospective study.

RESULTS

The length of all 19 tubular hand bones were measured in 144 individuals (age 6 to 57 years; 68 female) who had OI caused by COL1A1 or COL1A2 variants. Measurements of bone length were converted to z-scores using published reference data. Bone length was mostly normal in OI type I but was significantly decreased in OI types III and IV. Mean hand bone length z-score (i.e., the average length z-score of all 19 bones of a hand) was -0.2 for OI type I, -2.9 for OI type III and -1.2 for OI type IV. Mean hand bone length z-score was positively associated with height z-score (r² = 0.65, P < 0.001). Regarding genotype-phenotype correlations, mean hand bone length z-score was close to 0 in individuals with COL1A1 mutations leading to haploinsufficiency but were significantly lower in the presence of mutations leading to triple-helical glycine substitutions in either the alpha 1 or alpha 2 chain of collagen type I.

CONCLUSION

COL1A1 and COL1A2 mutations affect bone growth not only by inducing fractures and bone deformities, but also through longitudinal growth deficits in bones that do not fracture or deform.

TRPS1 mutation detection in Chinese patients with Tricho-rhino-phalangeal syndrome and identification of four novel mutations

Background

Tricho‐rhino‐phalangeal syndrome (TRPS) is a rare autosomal dominant disorder characterized by craniofacial and skeletal malformations including short stature, thin scalp hair, sparse lateral eyebrows, a pear‐shaped nose, and cone‐shaped epiphyses. This condition is caused by haploinsufficiency or dominant‐negative effect of the TRPS1 gene.

Methods

In this study, we analyzed the clinical and genetic data of five unrelated TRPS patients. They were suspected of having TRPS on the basis of clinical and radiological features including typical hair and facial features, as well as varying degrees of skeletal abnormalities. Next‐generation sequencing was performed to identify variants of the TRPS1 gene in the five patients.

Results

In patient 1, we found a novel mutation at c.1338C>A (p.Tyr446*) (de novo). Patient 2 had a novel phenotype of hydrocephaly and Arnold–Chiari syndrome and we also found a maternally inherited novel mutation at c.2657C>A (p.Ser886*). Patient 3 had a de novo novel mutation at c.2726G>C (p.Cys909Ser) leading to more severe phenotypes. Patient 4 had a paternally inherited known mutation at c.2762G>A (p.Arg921Gln). Patient 5 with a novel phenotype of hepatopathy had a novel deletion at [GRCh37] del(8)(q23.3‐q24.11) chr8:g.116,420,724‐119,124,058 (over 2,700 kb). In addition, the patient 3 who harboring missense variants in the GATA binding domain of TRPS1 showed more severe craniofacial and skeletal phenotypes.

Conclusions

We describe four novel mutations and two novel phenotypes in five patients. The mutational and phenotypic spectrum of TRPS is broadened by our study on TRPS mutations. Our results reveal the significance of molecular analysis of TRPS1 for improving the clinical diagnosis of TRPS.

Dual molecular diagnosis of tricho-rhino-phalangeal syndrome type I and Okur-Chung neurodevelopmental syndrome in one Chinese patient: a case report

Background

Okur-Chung neurodevelopmental syndrome (OCNDS) and tricho-rhino-phalangeal syndrome type I (TRPSI) are rare Mendelian diseases. OCNDS is caused by CSNK2A1 gene variants and TRPSI is caused by the TRPS1gene. However, to have two Mendelian diseases in one patient is even rarer.

Case presentation

A 6-year-10-month-old boy characterized by special facial features, short stature and mental retardation was referred to our pediatric endocrinology department. Whole-exome sequencing (WES) was done to detect the molecular basis of his disease. This patient was confirmed to carry two variants in the CSNK2A1 gene and one in the TRPS1 gene. The variant in the CSNK2A1 gene was vertically transmitted from his father, and the variant in TRPS1 gene from his mother. These two variants are classified as pathogenic and the causes of the presentation in this child. This patient’s father and mother have subsequently been diagnosed as having OCNDS and TRPSI respectively.

Conclusion

This is the first reported case of a dual molecular diagnosis of tricho-rhino-phalangeal syndrome type I and Okur-Chung neurodevelopmental syndrome in the same patient. This patient is the first published example of vertical transmission of this recurrent CSN2A1 variant from parent to child. A novel variant in the TRPS1 gene that is pathogenic was also identified. In conclusion, identification of the variants in this patient expands the phenotypes and molecular basis of dual Mendelian diseases.

Impaired dentin mineralization, supernumerary teeth, hypoplastic mandibular condyles with long condylar necks, and a TRPS1 mutation

Tricho-rhino-phalangeal syndrome type I, an autosomal dominant condition, is caused by heterozygous pathogenic variants in a zinc finger transcription factor, TRPS1, which has important roles in development of endochondral bones, teeth, and hair. Clinical manifestations of the patients include short stature, sparse, fine and slow-growing scalp hair, bulbous nose, supernumerary teeth, hip dysplasia, brachydactyly, and cone-shaped epiphyses of the phalangeal bones.

OBJECTIVE

To clinically, radiographically, and molecular genetically investigate a patient with tricho-rhino-phalangeal syndrome type I.

MATERIALS AND METHODS

Clinical and radiographic examination and mutation analysis of TRPS1 were performed.

RESULTS

Clinical and radiographic examination indicated the patient had tricho-rhino-phalangeal syndrome type I. Sequencing of the TRPS1 gene revealed a heterozygous pathogenic variant (c.2762G>A; p.Arg921Gln). Oral examination showed supernumerary teeth, large dental pulp spaces, dental pulp stones, microdontia of the maxillary permanent lateral incisors, absence of the mandibular left second premolar and short root of the maxillary right second premolar, and hypoplastic mandibular condyles with long condylar necks.

CONCLUSION

TRPS1 has an important function in regulating bone and dentin mineralization. Having large dental pulp spaces suggests that impaired dentin mineralization was the result of the TRPS1 pathogenic variant. This is the first patient with a TRPS1 pathogenic variant who had impaired dentin mineralization. This is also the third report showing the association between TRPS1 pathogenic variants and the presence of supernumerary teeth.

TRPS1 mutation associated with trichorhinophalangeal syndrome type 1 with 15 supernumerary teeth, hypoplastic mandibular condyles with slender condylar necks and unique hair morphology

Trichorhinophalangeal syndrome type 1 (TRPS1; Online Mendelian Inheritance in Man #190350) is an autosomal dominant disorder caused by mutations in TRPS1. We report a Thai male with TRPS1 who carried a c.1842C>T (p.Arg615Ter) mutation. He had 15 supernumerary teeth, double mental foramina, hypoplastic mandibular condyles with slender condylar necks and unique ultrastructural hair findings. Body hair was absent. The hair in the area of a congenital melanocytic nevus had a greater number of hair cuticles than normal. Occipital hair had abnormal hair follicles and cuticles. The scale edges of the hair cuticles were detached and rolled up. Hypoplastic mandibular condyles with slender condylar necks, double mental foramina and the rolled up edges of hair cuticles have not been reported in patients with TRPS1.

Association of Trichorhinophalangeal Syndrome and Loose Anagen Syndrome: A Case Report

Trichorhinophalangeal syndrome (TRPS) is an autosomal dominant disease characterized by trichologic, craniofacial, and musculoskeletal abnormalities. Predominant clinical features include a pear-shaped nose with bulbous tip, long philtrum, protruding ears, and sparse hair on both the scalp and the lateral third of the eyebrows. Cone-shaped epiphyses are a common radiographic finding. Loose anagen syndrome (LAS) is a sporadic or autosomal dominant condition due to abnormalities in the hair's anchoring mechanism. It mostly affects children, who usually have reduced hair length, as well as hair that is easily plucked without pain. Recent contributions regarding trichoscopic findings of LAS have been made, describing rectangular black granular structures as a typical feature. An association between TRPS and LAS has been mentioned by hair experts, but no reports documenting this have been published. This case demonstrates the co-existence of both conditions in a patient with characteristic phenotypic traits of TRPS and LAS.

Novel PLAG1 Gene Rearrangement Distinguishes a Subset of Uterine Myxoid Leiomyosarcoma From Other Uterine Myxoid Mesenchymal Tumors

Genetic alterations in uterine myxoid leiomyosarcoma are unknown. We investigate the clinicopathologic features of 19 uterine tumors previously diagnosed as myxoid leiomyosarcomas in which tumoral RNA was subjected to targeted RNA sequencing. PLAG1, BCOR, BCORL1, HMGA2, and ALK break-apart fluorescence in situ hybridization (FISH) and BCOR, PLAG1, and ALK immunohistochemistry were performed in cases which failed or lacked fusions by sequencing. The diagnosis of myxoid leiomyosarcoma was confirmed in 15 cases after exclusion of 4 tumors with BCOR and ALK rearrangements. These 15 patients presented at a median age of 50 years with stage I (3), II (2), III (2), and IV (1) tumors, respectively; stage was unknown in 7 cases. Tumor size ranged from 10 to 24 cm. Matrix was myxoid in all tumors and also eosinophilic in 2. Cells were spindled, epithelioid, and both in 10, 2, and 3 tumors and showed mild, moderate, and severe nuclear atypia in 3, 8, and 4 tumors, respectively. Mitotic index ranged from <1 to 14/10 HPF, while tumor necrosis was present in 6 (40%). Novel TRPS1-PLAG1 or RAD51B-PLAG1 fusions were detected by sequencing in 4 tumors, 3 of which were also confirmed by FISH. Diffuse PLAG1 expression was seen in 7 tumors, including 4 with PLAG1 rearrangement. No morphologic differences were seen among PLAG1 fusion-positive and fusion-negative tumors. No PLAG1, HMGA2, ALK, BCOR, or BCORL1 rearrangements were detected by FISH in 11 tumors. On the basis of sequencing and FISH results, PLAG1 rearrangements resulting in PLAG1 expression underpin ~25% of myxoid leiomyosarcomas and may serve as a useful diagnostic biomarker. Immunohistochemistry, targeted RNA sequencing, and/or FISH may distinguish myxoid leiomyosarcoma from its morphologic mimics.

An intragenic duplication of TRPS1 leading to abnormal transcripts and causing trichorhinophalangeal syndrome type I

Trichorhinophalangeal syndrome type I (TRPSI) is a rare disorder that causes distinctive ectodermal, facial, and skeletal features affecting the hair (tricho-), nose (rhino-), and fingers and toes (phalangeal) and is inherited in an autosomal dominant pattern. TRPSI is caused by loss of function variants in TRPS1, involved in the regulation of chondrocyte and perichondrium development. Pathogenic variants in TRPS1 include missense mutations and deletions with variable breakpoints, with only a single instance of an intragenic duplication reported to date. Here we report an affected individual presenting with a classic TRPSI phenotype who is heterozygous for a de novo intragenic ∼36.3-kbp duplication affecting exons 2–4 of TRPS1. Molecular analysis revealed the duplication to be in direct tandem orientation affecting the splicing of TRPS1. The aberrant transcripts are predicted to produce a truncated TRPS1 missing the nuclear localization signal and the GATA and IKAROS-like zinc-finger domains resulting in functional TRPS1 haploinsufficiency. Our study identifies a novel intragenic tandem duplication of TRPS1 and highlights the importance of molecular characterization of intragenic duplications.

Severe brachydactyly and short stature resulting from a novel pathogenic TRPS1 variant within the GATA DNA-binding domain

Brachydactyly type E, which can be an isolated finding or part of a syndrome in combination with other clinical anomalies, involves metacarpals and metatarsals with or without short phalanges. Herein we report two unrelated Turkish females who presented with brachydactyly type E and vitamin D deficiency in the absence of marked alterations in serum calcium, phosphate, and parathyroid hormone. After excluding disease-causing variants in two candidate genes, PTHLH and PDE4D, we identified different pathogenic variants in TRPS1, the gene mutated in patients with tricho-rhino-phalangeal syndrome (TRPS). In one of the patients, who displayed severe brachydactyly and short stature, we identified a novel heterozygous missense pathogenic variant in exon 6 (c.2783A>G, p.Tyr928Cys), located within the GATA DNA-binding domain. The second patient, who had relatively milder brachydactyly and was of normal height, carried a heterozygous nonsense pathogenic variant in exon 4 (c. 1870C>T, p.Arg624Ter), which has been previously described. Both pathogenic variants segregated in affected family members. The patients additionally showed sparse hair and a bulbous nose, consistent with the clinical features of TRPS. Our findings, in addition to identifying the genetic cause of brachydactyly in two unrelated kindreds, emphasize the role of pathogenic TRPS1 variants in the development of brachydactyly type E and highlight the GATA DNA-binding region of TRPS1 protein with respect to phenotype-genotype correlation.

Trps1 Regulates Development of Craniofacial Skeleton and Is Required for the Initiation of Palatal Shelves Fusion

Trichorhinophalangeal syndrome (TRPS) is an autosomal dominant disorder resulting from heterozygous mutations of the TRPS1 gene. Common craniofacial abnormalities in TRPS patients include micrognathia, hypoplastic zygomatic arch, high-arched palate, and, occasionally, cleft palate. Studies have demonstrated that mice with a heterozygous Trps1 mutation (Trps1^+/− mice) have similar features to patients with TRPS, including high-arched palates. However, mice with a homozygous Trps1 mutation (Trps1^−/− mice) exhibit similar but more severe abnormalities, including cleft palate. Our study aimed to characterize the craniofacial phenotype to understand the role of Trps1 in craniofacial development and gain insight on the cleft palate pathogenesis in Trps1 deficiency. Whole-mount skeletal staining revealed hypoplastic skeletal and cartilaginous elements, steep nasal slope, and missing presphenoid in Trps1^−/− mice. Although several craniofacial skeleton elements were abnormal in Trps1^−/− mice, the Trps1 deficiency did not appear to disrupt cranial vault development. All Trps1^−/− mice presented with cleft palate. Analyses of Trps1 expression during palatogenesis detected Trps1 mRNA and protein in palatal mesenchyme and in specific regions of palatal epithelium, which suggested that Trps1 is involved in palatal fusion. Ex vivo culture experiments demonstrated that Trps1^−/− palatal shelves were unable to initiate the fusion process. On the molecular level, Trps1 deficiency resulted in decreased epithelial expression of proteins involved in palatal fusion, including chondroitin sulfate proteoglycan, transforming growth factor-beta 3, Twist1, and beta-catenin. Mesenchymal expression of chondroitin sulfate proteoglycan expression was unaffected, indicating a cell type-specific mechanism of Trps1 regulation on chondroitin sulfate proteoglycan. In conclusion, we demonstrated that Trps1 is involved in the development of craniofacial skeletal elements and in the initiation of the palatal shelves fusion. Furthermore, our studies uncovered that Trps1 is required for epithelial expression of several proteins involved in the palatal shelves fusion.

Trps1 transcription factor regulates mineralization of dental tissues and proliferation of tooth organ cells

Mutations of the TRPS1 gene cause trichorhinophalangeal syndrome (TRPS), a skeletal dysplasia with dental abnormalities. TRPS dental phenotypes suggest that TRPS1 regulates multiple aspects of odontogenesis, including the tooth number and size. Previous studies delineating Trps1 expression throughout embryonic tooth development in mice detected strong Trps1 expression in dental mesenchyme, preodontoblasts, and dental follicles, suggesting that TRPS dental phenotypes result from abnormalities in early developmental processes. In this study, Trps1^+/- and Trps1^-/- mice were analyzed to determine consequences of Trps1 deficiency on odontogenesis. We focused on the aspects of tooth formation that are disturbed in TRPS and on potential molecular abnormalities underlying TRPS dental phenotypes. Microcomputed tomography analyses of molars were used to determine tooth size, crown shape, and mineralization of dental tissues. These analyses uncovered that disruption of one Trps1 allele is sufficient to impair mineralization of dentin in both male and female mice. Enamel mineral density was decreased only in males, while mineralization of the root dental tissues was decreased only in females. In addition, significantly smaller teeth were detected in Trps1^+/- females. Histomorphometric analyses of tooth organs showed reduced anterior-posterior diameter in Trps1^-/- mice. BrdU-incorporation assay detected reduced proliferation of mesenchymal and epithelial cells in Trps1^-/- tooth organs. Immunohistochemistry for Runx2 and Osx osteogenic transcription factors revealed changes in their spatial distribution in Trps1^-/- tooth organs and uncovered cell-type specific requirements of Trps1 for Osx expression. In conclusion, this study has demonstrated that Trps1 is a positive regulator of cell proliferation in both dental mesenchyme and epithelium, suggesting that the microdontia in TRPS is likely due to decreased cell proliferation in developing tooth organs. Furthermore, the reduced mineralization observed in Trps1^+/- mice may provide some explanation for the extensive dental caries reported in TRPS patients.

Trps1-deficient transplanted skin gave rise to a substantial amount of hair: Trps1 is unnecessary for hair development

Trps1 is considered as an important gene involved in the interactions between the epithelial and mesenchymal cells during hair follicle morphogenesis. The number of hair follicles in Trps1 Knockout (KO) newborn mouse skin was significantly lower than that in wild-type (WT) newborn skin. To gain insight into the functional role of Trps1 in hair development, we transplanted Trps1 KO newborn mouse skin on the backs of nude mice and examined hair growth at day 42 after transplantation. Surprisingly, transplanted skin from Trps1 KO newborn mice gave rise to a substantial amount of hair, although the hair was softer than that of WT mice. Histological examination revealed that the diameter of both hair follicles and hair shafts were significantly lower, whereas the density of hair follicles showed no significant difference between the Trps1 KO and WT mice. We introduce mouse hair follicles as a fascinating model to study the functions of Trps1 in mouse hair growth and pathology. This model suggests that the function of Trps1 is unnecessary for the development of normal hair follicles and hair shafts, although the loss of Trps1 affects the diameters of hair follicles and hair shaft.

Non-ossifying fibroma with a pathologic fracture in a 12-year-old girl with tricho-rhino-phalangeal syndrome: a case report

Background

Tricho-rhino-phalangeal syndrome (TRPS) is a rare autosomal dominant genetic disorder characterized by distinctive craniofacial and skeletal abnormalities, while non-ossifying fibroma (NOF) is a common benign bone tumour in children and adolescents. To date, no case of TRPS coexisting with NOF has been reported. This report presents a 12-year-old girl who had the characteristic features of tricho-rhino-phalangeal syndrome and non-ossifying fibroma with a fibula fracture.

Case presentation

A 12-year-old girl was admitted to the Department of Endocrinology and Diabetes for evaluation of brachydactyly and a right fibula fracture. Clinical examination revealed sparse scalp hair, a characteristic bulbous pear-shaped nose, and brachydactyly with significant shortening of the fourth metatarsal. Neither intellectual disability nor multiple exostoses were observed. Radiography of both hands showed brachydactyly and cone-shaped epiphyses of the middle phalanges of the digits of both hands with deviation of the phalangeal axis. Genetic analysis of TRPS1 identified a heterozygous germline sequence variant (p.Ala932Thr) in exon 6 in the girl and her father. Approximately 1 month before being admitted to our department, the girl experienced a minor fall and suffered a fracture of the proximal fibula in the right lower limb. The pathological cytological diagnosis of the osteolytic lesion was NOF. Ten months following the surgery, the lesion on the proximal fibula of the girl disappeared.

Conclusions

In conclusion, the present study is the first to report a rare case of NOF with a pathologic fracture in the fibula of a girl with TRPS. The identification of a missense mutation, (p.Ala932Thr), in exon 6 of TRPS1 in this kindred further suggested that the patient had type I TRPS and indicated that mutations in this exon may be correlated with more pronounced features of the syndrome. Radiological techniques and genetic analysis played key roles in the definitive diagnosis.

Electronic supplementary material

The online version of this article (10.1186/s12881-018-0732-4) contains supplementary material, which is available to authorized users.

Dysmorphic Short Stature: Radiological Diagnosis of Trichorhinophalangeal Syndrome

Trichorhinophalangeal syndrome (TRPS), a type of skeletal dysplasia, is characterized by a triad of dysmorphic (bulbous nose and large ears); ectodermal (thin and sparse hair); and skeletal (short stature and cone-shaped epiphyses) findings, and this combination is helpful for early diagnosis and appropriate follow-up. A 14-year-old boy presented with short stature and distinctive facial features, and following the first clinical and biological evaluation, no precise diagnosis was reached. Progressive bilateral development of noninflammatory and painless deformity of his second finger required a radiological exam that highlighted the key elements (cone-shaped epiphyses) for final diagnosis. This case illustrates the difficulties to early recognition of TRPS when the clinical presentation is not complete and radiological findings are missing.

An early diagnosis of trichorhinophalangeal syndrome type 1: a case report and a review of literature

Background

Trichorhinophalangeal syndrome (TRPS) is a rare autosomal dominant disorder caused by defects involving the TRPS1 gene. It exhibits distinctive craniofacial, ectodermal and skeletal abnormalities, such as sparse hair, bulbous nasal tip and short deformed fingers, with extremely variable expressivity.

Case presentation

We report the case of a 17 months old girl, who presented growth retardation and dysmorphic features. Postnatal growth was always below − 2 Standard Deviation for both weight and length and physical examination revealed relative macrocephaly, sparse hair, bulbous nasal tip, thin upper lip, protruding ears, prominent forehead, small jaw, and short hands and feet. Patient’s mother shared the same facial features, and presented sparse hair and small hands. The maternal grandfather and two uncles presented short stature, bulbous nasal tip, thin hair, and premature alopecia. Molecular analysis of TRPS1 gene showed a heterozygous c.2086C > T;(p.Arg696Ter) mutation both in the patient and her mother, confirming the diagnosis of TRPS, type I.

Conclusions

Clinical phenotype of TRPS can be subtle and the syndrome often remains undiagnosed. A comprehensive clinical examination and an exhaustive family history are crucial to reach the correct diagnosis, which is essential to perform adequate follow-up and timely therapeutic procedures.

Multiple long bone cysts revealed by MRI in trichorhinophalangeal syndrome type II predisposing to pathological fractures

Trichorhinophalangeal syndrome type II is a rare genetic disorder with the few published case reports mainly reporting the radiographic skeletal manifestations. There are no published imaging reports of long bone cysts involving multiple bones in this condition. We report a unique case of bone cysts involving multiple long bones detected with MRI in a patient with trichorhinophalangeal syndrome type II complicated by a subsequent pathological fracture. It is possible that the bone cysts are a previously undescribed feature of this syndrome; however, the evidence is insufficient to establish a definite association. Chromosomal abnormality identified in this patient is consistent with trichorhinophalangeal syndrome type II with no unusual features. Although the nature of these bone cysts is unclear, they are one of the causes of the known increased fracture risk observed in this syndrome.

A novel TRPS1 mutation in a Moroccan family with Tricho-rhino-phalangeal syndrome type III: case report

BACKGROUND

Tricho-rhino-phalangeal syndrome (TRPS) is an autosomal dominant disorder characterized by craniofacial and skeletal malformations including short stature, thin scalp hair, sparse lateral eyebrows, pear-shaped nose and cone shaped epiphyses. This condition is caused by haploinsufficiency of the TRPS1 gene. Previous genotype-phenotype studies have correlated exon 6 missense mutations with TRPS type III, a severe form of type I with pronounced, facial characteristics, short stature and brachydactyly and differing from type II by the absence of exostoses and mental retardation.

CASE PRESENTATION

We report the first case of a Moroccan family, a father and his three children, in which the diagnosis of type III TRPS was suspected based on severe clinical and radiological features. Molecular analysis of the TRPS1 gene revealed a novel missense mutation in exon 6, (p.Ala932Ser), located in the GATA-type DNA-binding zinc finger domain.

CONCLUSION

Our observations in this kindred support the previous genotype-phenotype results suggesting that patients with more pronounced facial characteristics and more severe shortening of hands and feet are more likely to have mutation in exon 6 of TRPS1.

Isolated brachydactyly type E and idiopathic pancreatitis in a patient presenting to a lipid disorders clinic

An 18-year-old female tertiary student was referred to a lipid clinic with hypertriglyceridaemia discovered after presentation with acute pancreatitis. The patient's only medication was l-thyroxine for treatment of hypothyroidism. She was overweight, normotensive, with unremarkable facies. However, she had hypermobile hand joints and brachydactyly resulting in loss of left 3-5 and right 4 and 5 knuckle definitions. Radiography revealed shortening of metacarpals 3-5 on the left and 4 and 5 on the right. Her mother had similar skeletal changes, consistent with a dominant mode of inheritance. Abnormally short digits involving the metacarpals, classified as brachydactyly type E, can be isolated or occur as part of a syndrome. Turner syndrome, Albright hereditary osteodystrophy, hypertension with brachydactyly, chromosome 2q37 microdeletion and PTHLH mutations were excluded following clinical, biochemical and genetic testing. No specific treatment was required. Genetic testing for isolated and syndromic forms of brachydactyly facilitates family screening and prepregnancy counselling.