Short root anomaly associated with Rothmund-Thomson syndrome

Presentation of a Case of Short Root Anomaly in an 11-Year-Old Child

Short root anomaly (SRA) is a developmental anomaly in which the affected teeth present morphologically normal crowns and short, round roots. The exact cause of SRA is unknown. A case of an 11-year-old female patient with SRA is described. The patient presented short, round roots of all permanent teeth but first molars. Maxillary lateral incisors presented severe root resorption and mobility. Treatment plan included preservation of the maxillary lateral incisors by splinting them to their adjacent teeth using a stainless steel coaxial wire. A custom mouthguard for dental trauma protection was also constructed using a computer-aided design - computer-aided manufacturing (CAD-CAM) system in order to fabricate 3D-printed dental casts. At 2-year follow-up, the mobility of maxillary lateral incisors decreased, and the patient's dentition remained stable. Considerations regarding differential diagnosis, orthodontic management, and treatment options after an eventual loss of teeth are thoroughly discussed.

Report of Two Novel Mutations in Indian Patients with Rothmund-Thomson Syndrome

Rothmund-Thomson syndrome (RTS) is a rare autosomal recessive disorder caused by mutations in RECQL4 and has characteristic clinical features. We report two unrelated phenotypically diverse patients (cases 1 and 2) with RTS having novel variants in RECQL4 gene . Case-1 was evaluated for poor growth and recurrent fractures and skin lesions. Case-2 presented at 4 months with failure to thrive and radial ray defect and developed poikilodermatous skin lesions after infancy. Both cases were confirmed to have homozygous pathogenic variants in RECQL4 . Both patients have normal intellect and are on supportive therapy. The presence of characteristic poikiloderma lesions with specific distribution and skeletal anomalies in a patient with proportionate short stature is a clue toward the diagnosis of RTS.

Orthodontic management of a patient with short root anomaly and impacted teeth

Short root anomaly (SRA) is a rare familial dental condition that is often misdiagnosed. Orthodontic treatment of patients with SRA is challenging because it is difficult to diagnose, it may be accompanied by other dental anomalies, and it has been reported to contribute to additional susceptibility to root resorption during orthodontic treatment. In this article, we describe a methodical and evidence-based means of diagnosing and orthodontically managing a patient with SRA. The patient had additional challenges, including impacted and ectopic teeth. An individualized treatment plan that incorporated efficient and effective mechanics led to a well seated occlusion and an esthetic smile.

Dental management of Rothmund-Thomson syndrome with partial anodontia

Rothmund-Thomson syndrome (RTS) is a rare autosomal recessive trait disease. It is characterised by skin, eye and skeletal abnormalities. Abnormalities associated with teeth include abnormal crown and root formations, rudimentary or hypoplastic teeth, microdontia and multiple missing teeth. In the present case, there were multiple decayed primary teeth and multiple congenitally missing permanent teeth. Mandibular left primary first molar (tooth 74) was pulpally involved and obturated with mineral trioxide ggregate. Follow-up after 2 years revealed successful obturation.

Regulatory mechanisms of Hertwig׳s epithelial root sheath formation and anomaly correlated with root length

Teeth are composed of two domains, the enamel-covered crown and cementum-covered root. The mechanism for determining the transition from crown to root is important for understanding root anomaly diseases. Hertwig׳s epithelial root sheath (HERS) is derived from the dental epithelium and is known to drive the growth of root dentin and periodontal tissue. Some clinical cases of hypoplastic tooth root are caused by the cessation of HERS development. Understanding the mechanisms of HERS development will contribute to the study of the disease and dental regenerative medicine. However, the developmental biology of tooth root formation has not been fully studied, particularly regarding HERS formation. Here, we describe the mechanisms of HERS formation on the basis of analysis of cell dynamics using imaging and summarize how the growth factor and its receptor regulate cell behavior of the dental epithelium.

Atypical meningioma as a solitary malignancy in a patient with Rothmund-Thompson syndrome

Background:

Rothmund-Thomson syndrome (RTS) is a rare autosomal recessive disorder characterized by genomic instability and increased risk of various malignancies, especially osteosarcoma and squamous cell carcinoma. We report the first RTS patient who developed a central nervous system (CNS)-related neoplasm.

Case description:

A 28-year-old male, previously diagnosed with RTS , developed a massive parasagital lesion, detected by magnetic resonance imaging. The tumor was surgically removed and histologically diagnosed as atypical meningioma. Preoperative symptoms were dramatically improved.

Conclusions:

This is the first description of a CNS-related malignancy in RTS patients. Although rare, the genomic instability and additional risk factors of this syndrome should be considered in choosing the course of treatment.

Dental approach to craniofacial syndromes: how can developmental fields show us a new way to understand pathogenesis?

The paper consists of three parts. Part 1: Definition of Syndromes. Focus is given to craniofacial syndromes in which abnormal traits in the dentition are associated symptoms. In the last decade, research has concentrated on phenotype, genotype, growth, development, function, and treatment. Part 2: Syndromes before Birth. How can the initial malformation sites in these syndromes be studied and what can we learn from it? In this section, deviations observed in syndromes prenatally will be highlighted and compared to the normal human embryological craniofacial development. Specific focus will be given to developmental fields studied on animal tissue and transferred to human cranial development. Part 3: Developmental Fields Affected in Two Craniofacial Syndromes. Analysis of primary and permanent dentitions can determine whether a syndrome affects a single craniofacial field or several fields. This distinction is essential for insight into craniofacial syndromes. The dentition, thus, becomes central in diagnostics and evaluation of the pathogenesis. Developmental fields can explore and advance the concept of dental approaches to craniofacial syndromes. Discussion. As deviations in teeth persist and do not reorganize during growth and development, the dentition is considered useful for distinguishing between syndrome pathogenesis manifested in a single developmental field and in several fields.

Cell dynamics in cervical loop epithelium during transition from crown to root: implications for Hertwig's epithelial root sheath formation

BACKGROUND AND OBJECTIVE

Some clinical cases of hypoplastic tooth root are congenital. Because the formation of Hertwig's epithelial root sheath (HERS) is an important event for root development and growth, we have considered that understanding the HERS developmental mechanism contributes to elucidate the causal factors of the disease. To find integrant factors and phenomenon for HERS development and growth, we studied the proliferation and mobility of the cervical loop (CL).

MATERIAL AND METHODS

We observed the cell movement of CL by the DiI labeling and organ culture system. To examine cell proliferation, we carried out immunostaining of CL and HERS using anti-Ki67 antibody. Cell motility in CL was observed by tooth germ slice organ culture using green fluorescent protein mouse. We also examined the expression of paxillin associated with cell movement.

RESULTS

Imaging using DiI labeling showed that, at the apex of CL, the epithelium elongated in tandem with the growth of outer enamel epithelium (OEE). Cell proliferation assay using Ki67 immunostaining showed that OEE divided more actively than inner enamel epithelium (IEE) at the onset of HERS formation. Live imaging suggested that mobility of the OEE and cells in the apex of CL were more active than in IEE. The expression of paxillin was observed strongly in OEE and the apex of CL.

CONCLUSION

The more active growth and movement of OEE cells contributed to HERS formation after reduction of the growth of IEE. The expression pattern of paxillin was involved in the active movement of OEE and HERS. The results will contribute to understand the HERS formation mechanism and elucidate the cause of anomaly root.

Rothmund-Thomson syndrome

Rothmund-Thomson syndrome (RTS) is a genodermatosis presenting with a characteristic facial rash (poikiloderma) associated with short stature, sparse scalp hair, sparse or absent eyelashes and/or eyebrows, juvenile cataracts, skeletal abnormalities, radial ray defects, premature aging and a predisposition to cancer. The prevalence is unknown but around 300 cases have been reported in the literature so far. The diagnostic hallmark is facial erythema, which spreads to the extremities but spares the trunk, and which manifests itself within the first year and then develops into poikiloderma. Two clinical subforms of RTS have been defined: RTSI characterised by poikiloderma, ectodermal dysplasia and juvenile cataracts, and RTSII characterised by poikiloderma, congenital bone defects and an increased risk of osteosarcoma in childhood and skin cancer later in life. The skeletal abnormalities may be overt (frontal bossing, saddle nose and congenital radial ray defects), and/or subtle (visible only by radiographic analysis). Gastrointestinal, respiratory and haematological signs have been reported in a few patients. RTS is transmitted in an autosomal recessive manner and is genetically heterogeneous: RTSII is caused by homozygous or compound heterozygous mutations in the RECQL4 helicase gene (detected in 60-65% of RTS patients), whereas the aetiology in RTSI remains unknown. Diagnosis is based on clinical findings (primarily on the age of onset, spreading and appearance of the poikiloderma) and molecular analysis for RECQL4 mutations. Missense mutations are rare, while frameshift, nonsense mutations and splice-site mutations prevail. A fully informative test requires transcript analysis not to overlook intronic deletions causing missplicing. The diagnosis of RTS should be considered in all patients with osteosarcoma, particularly if associated with skin changes. The differential diagnosis should include other causes of childhood poikiloderma (including dyskeratosis congenita, Kindler syndrome and Poikiloderma with Neutropaenia), other rare genodermatoses with prominent telangiectasias (including Bloom syndrome, Werner syndrome and Ataxia-telangiectasia) and the allelic disorders, RAPADILINO syndrome and Baller-Gerold syndrome, which also share some clinical features. A few mutations recur in all three RECQL4 diseases. Genetic counselling should be provided for RTS patients and their families, together with a recommendation for cancer surveillance for all patients with RTSII. Patients should be managed by a multidisciplinary team and offered long term follow-up. Treatment includes the use of pulsed dye laser photocoagulation to improve the telangiectatic component of the rash, surgical removal of the cataracts and standard treatment for individuals who develop cancer. Although some clinical signs suggest precocious aging, life expectancy is not impaired in RTS patients if they do not develop cancer. Outcomes in patients with osteosarcoma are similar in RTS and non-RTS patients, with a five-year survival rate of 60-70%. The sensitivity of RTS cells to genotoxic agents exploiting cells with a known RECQL4 status is being elucidated and is aimed at optimizing the chemotherapeutic regimen for osteosarcoma.