Anomalies of tooth formation in hypohidrotic ectodermal dysplasia

Craniofacial syndromes and class III phenotype: common genotype fingerprints? A scoping review and meta-analysis

Skeletal Class III (SCIII) is among the most challenging craniofacial dysmorphologies to treat. There is, however, a knowledge gap regarding which syndromes share this clinical phenotype. The aims of this study were to: (i) identify the syndromes affected by the SCIII phenotype; (ii) clarify the involvement of maxillary and/or mandibular structures; (iii) explore shared genetic/molecular mechanisms. A two-step strategy was designed: [Step#1] OMIM, MHDD, HPO, GeneReviews and MedGen databases were explored; [Step#2]: Syndromic conditions indexed in [Step#1] were explored in Medline, Pubmed, Scopus, Cochrane Library, WOS and OpenGrey. Eligibility criteria were defined. Individual studies were assessed for risk of bias using the New Ottawa Scale. For quantitative analysis, a meta-analysis was conducted. This scoping review is a hypothesis-generating research. Twenty-two studies met the eligibility criteria. Eight syndromes affected by the SCIII were targeted: Apert syndrome, Crouzon syndrome, achondroplasia, X-linked hypohidrotic ectodermal dysplasia (XLED), tricho-dento-osseous syndrome, cleidocranial dysplasia, Klinefelter and Down syndromes. Despite heterogeneity between studies [p < 0.05], overall effects showed that midface components were affected in Apert and Down Syndromes, lower face in Klinefelter Syndrome and midface and lower face components in XLED. Our review provides new evidence on the craniofacial characteristics of genetically confirmed syndromes exhibiting the SCIII phenotype. Four major regulatory pathways might have a modulatory effect on this phenotype. IMPACT: What does this review add to the existing literature? To date, there is no literature exploring which particular syndromes exhibit mandibular prognathism as a common trait. Through this research, it was possibly to identify the particular syndromes that share the skeletal Class III phenotype (mandibular prognathism) as a common trait highlighting the common genetic and molecular pathways between different syndromes acknowledging their impact in craniofacial development.

Bimaxillary fixed implant-supported zirconium oxide prosthesis therapy of an adolescent patient with non-syndromic oligodontia and two WNT10 variants: a case report

Introduction and importance

Oligodontia is a rare genetic condition characterized by more than six congenitally missing teeth, either as an isolated non-syndromic condition or in association with other genetic syndromes. The impact of WNT10A variants on dental development increases with the presence of the c.321C>A variant and the number of missing teeth.

Case presentation

A 21-year-old man with non-syndromic oligodontia was diagnosed at 15 years of age with misaligned teeth, speech problems, and the absence of 24 permanent teeth. Interdisciplinary collaboration between specialists was initiated to enable comprehensive treatment. DNA analysis confirmed that the patient was a carrier of the known pathogenic WNT10A variant c321C>A and WNT10A variant c.113G>T of unknown clinical significance.

Clinical discussion

Dental implants are a common treatment; however, bone development challenges in adolescent patients with non-syndromic oligodontia necessitate careful planning to ensure implant success. Many WNT variants play crucial roles in tooth development and are directly involved in non-syndromic oligodontia, especially the WNT10 variant c.321C>A.

Conclusion

A full-arch implant-supported monolithic zirconia screw-retained fixed prosthesis is a viable treatment option for young adults with non-syndromic oligodontia. Further studies are needed to clarify the possible amplifying effect of the WNT10A variants c321C>A and c.113G>T on the pathogenic phenotype of non-syndromic oligodontia.

Hair Evaluation in Orthodontic Patients with Oligodontia

Oligodontia can be isolated or syndromic, associated with other ectodermal abnormalities. The aim of the study was to perform hair examination in orthodontic patients diagnosed with oligodontia with a low clinical expression of symptoms of ectodermal origin. All available orthodontic patients diagnosed with oligodontia in the permanent dentition were enrolled. Hair examination included clinical evaluation of the patients' hair, trichoscopy, trichogram and evaluation of the hair shafts under a polarized light microscope. In total, 25 patients, 18 males and 7 females, aged 6 to 24 years were evaluated for the presence of dental and hair abnormalities. The number of congenitally absent teeth ranged from 6 to 24 teeth and diastemas, microdontia, taurodontism and altered tooth shape were found in 23 patients. Hair disorders were found in 68% of the subjects. Hypotrichosis, the heterogeneity of shaft color and loss of pigment, androgenetic alopecia, telogen effluvium, trichoschisis, pili canaliculi, trichorrhexis nodosa and pseudomoniletrix were observed. Trichoscopy and trichogram are valid non-invasive diagnostic tests which could be used to differentiate between isolated and syndromic oligodontia in patients with a low clinical expression of ectodermal symptoms.

Radiographic Orofacial Findings of Systemic Diseases

This article discusses the orofacial clinicoradiographic features of systemic diseases that manifest in the orofacial region. The systemic diseases discussed are grouped into the following: autoimmune diseases, endocrine diseases, bone diseases, hematologic diseases, syndromes, and malignancies. The radiographic manifestation ranges from radiolucent bony destruction, increased bone density, calcification, thinning of cortical plate, loss of trabeculation, missing teeth, and supernumerary teeth. It is imperative for clinicians to be cognizant of these findings, as they may be the first manifestation of these systemic diseases.

The oligodontia phenotype in a X-linked hypohidrotic ectodermal dysplasia patient with a novel EVC2 variant

Objectives

To analyse the pathogenic genes in a patient with hypohidrotic ectodermal dysplasia (HED) and explore the relationship between pathogenic genes and the oligodontia phenotype.

Methods

Clinical data and peripheral blood were collected from a patient with HED. Pathogenic genes were analysed by whole-exon sequencing (WES) and verified by Singer sequencing. The secondary and tertiary structures of the variant proteins were predicted to analyse their toxicity.

Results

The patient exhibited a severe oligodontia phenotype, wherein only two deciduous canines were left in the upper jaw. WES revealed a hemizygous EDA variant c.466C > T p.(Arg156Cys) and a novel heterozygous EVC2 variant c.1772T > C p.(Leu591Ser). Prediction of the secondary and tertiary structures of the EDA variant p.(Arg156Cys) and EVC2 variant p.(Leu591Ser) indicated impaired function of both molecules.

Conclusion

The patient demonstrated a more severe oligodontia phenotype when compared with the other patients caused by the EDA variant c.466C > T. Since Evc2 is a positive regulator of the Sonic Hedgehog (Shh) signal pathway, we speculated that the EVC2 variant p.(Leu591Ser) may play a synergistic role in the oligodontia phenotype of HED, thereby exacerbating the oligodontia phenotype. Knowledge of oligodontia caused by multiple gene variants is of great significance for understanding individual differences in oligodontia phenotypes.

A Missense Mutation in the Collagen Triple Helix of EDA Is Associated with X-Linked Recessive Hypohidrotic Ectodermal Dysplasia in Fleckvieh Cattle

Mutations within the ectodysplasin A (EDA) gene have been associated with congenital hypotrichosis and anodontia (HAD/XHED) in humans, mice, dogs and cattle. We identified a three-generation family of Fleckvieh cattle with male calves exhibiting clinical and histopathological signs consistent with an X-linked recessive HAD (XHED). Whole genome and Sanger sequencing of cDNA showed a perfect association of the missense mutation g.85716041G>A (ss2019497443, rs1114816375) within the EDA gene with all three cases following an X-linked recessive inheritance, but normal EDAR and EDARADD. This mutation causes an exchange of glycine (G) with arginine (R) at amino acid position 227 (p.227G>R) in the second collagen triple helix repeat domain of EDA. The EDA variant was associated with a significant reduction and underdevelopment of hair follicles along with a reduced outgrowth of hairs, a complete loss of seromucous nasolabial and mucous tracheal and bronchial glands and a malformation of and reduction in number of teeth. Thermostability of EDA G227R was reduced, consistent with a relatively mild hair and tooth phenotype. However, incisors and canines were more severely affected in one of the calves, which correlated with the presence of a homozygous missense mutation of RNF111 (g.51306765T>G), a putative candidate gene possibly associated with tooth number in EDA-deficient Fleckvieh calves.

A new variant of the ectodysplasin A receptor death domain gene associated with anhidrotic ectodermal dysplasia in a Turkish family and its simple diagnosis by restriction fragment length polymorphism

Ectodermal dysplasia (ED), which exhibits a wide range of clinical symptoms, may be classified into three major types: hypohidrotic, anhidrotic, and hidrotic. A male child (proband) showing anhidrotic dysplasia was used as the subject of this study. The biopsy of the big toe revealed that the male child had no sweat glands. Genetic analysis of the patient revealed a mutation caused by a homozygous nucleotide substitution in the EDAR-associated death domain (EDARADD) (rs114632254) gene c.439G>A (p.Gly147Arg). Phenotypically, his teeth were sharp, but eight teeth were missing (oligodontia). The patient had normal nails with dry skin, sparse hair, everted lower lip vermilion, hyperpigmented eyelids, and abnormal nasal bridge morphology around the eyes. There is also a homozygous dominant (healthy) female and a heterozygous male in this family, who are cousins (aunt children) to the heterozygous parents. The daughter of the patient was also heterozygous. This mutation represents homozygous recessive inheritance, which we describe for the first time. Furthermore, we demonstrated that this genetic disorder can be readily diagnosed using the restriction fragment length polymorphism (RFLP) method after digestion with MnII restriction endonuclease.

Dental age, agenesis, and morphological anomalies in individuals with Van der Woude syndrome and isolated cleft palate

OBJECTIVES

To analyse the differences between dental age and chronological age and dental anomalies in individuals with Van der Woude syndrome (VWS) and compare with non-syndromic cleft palate (NSCP) and non-cleft controls.

MATERIALS AND METHODS

In total, 204 oral panoramic radiographs (118 girls and 86 boys) consisting of 51 VWS patients (age x̅ = 8.17 ± 1.34 years), 51 NSCP patients (age x̅ = 8.09 ± 1.41 years), and 102 normative non-cleft children (age x̅ = 8.62 ± 1.24 years) were collected. Dental stages were assessed by the Demirjian method, with the local dental maturity index as reference. Dental anomalies including agenesis were investigated. Statistical differences were determined by One-way ANOVA and regression. Repeatability was calculated by an intra-class correlation test and 95% confidence interval.

RESULTS

The difference between dental age and chronological age of the VWS group (0.12 years) and the NSCP group (0.09 years) was significantly lower than the non-cleft group (0.40 years) (P = 0.002). There was no significant difference between the VWS and NSCP groups (P = 0.885). Hypodontia was more prevalent in both the VWS group (37.25%, P = 0.0001) and the NSCP group (19.60%, P = 0.035) compared with the non-cleft group (5.88%). The odds for hypodontia in the VWS group were approximately double compared with the NSCP group. In VWS patients, the most commonly missing teeth were the permanent second premolars and the maxillary permanent laterals incisors. Peg-shaped teeth had a prevalence of 13.70% in VWS patients.

CONCLUSIONS

In VWS and NSCP patients compared with non-cleft children, the difference in dental age compared with chronological age decreased. Hypodontia occurs at a high prevalence in VWS and NSCP patients compared with non-cleft children.

The characterization of hypodontia, hypohidrosis, and hypotrichosis associated with X-linked hypohidrotic ectodermal dysplasia: A systematic review

The objective of this study was to review the published literature on X-linked hypohidrotic ectodermal dysplasia (XLHED) for the prevalence and characteristics of three features of XLHED: hypodontia, hypohidrosis, and hypotrichosis. A systematic search of English-language articles was conducted in May 2019 to identify publications with information on any of the three features of XLHED. We excluded studies with five or fewer participants, that did not specify X-linked inheritance or an EDA mutation, and discussed only management of features. The weighted means for total missing teeth, location of missing teeth, prevalence of reduced and absent sweating ability, and sparse or absent hair were analyzed across all studies. Additional findings for hypodontia, hypohidrosis, and hypotrichosis were summarized qualitatively. Twenty publications (18 studies) were accepted. Reported findings for males tended to be more informative than for carrier females. The weighted mean for missing teeth for affected males was 22.4 (range: 10-28) and carrier females was 3.4 (range: 0-22). The most common conserved teeth for males were the canines. The most common missing teeth for females were the maxillary lateral incisors. The weighted mean prevalence of reduced or absent sweating ability was 95.7% for males and 71.6% for females. The weighted mean prevalence for hypotrichosis was 88.1% for males and 61.6% for females. This systematic review provides insight into the prevalence, characteristics, and variability of the three classic features of XLHED. These findings provide detailed natural history information for families with XLHED as well as key characteristics that can aid in diagnosis.

Prosthodontic Management of a Pediatric Patient with Christ-Siemens-Touraine Syndrome: A Case Report

Ectodermal dysplasias (ED) are a group of rare genetic disorders characterized by congenital defects involving two or more ectodermal structures. Christ-Siemens-Touraine syndrome or hypohidrotic ectodermal dysplasia is the commonest form of ED. Hypohidrotic ectodermal dysplasia (HED) is an X-linked disorder characterized by excessively dry skin due to the absence of sweat glands (anhidrosis), sparse body hair especially on the scalp and eyebrows (hypotrichosis), brittle nails, absence of sebaceous glands (asteatosis) and malformed or absent teeth. Oral manifestations include oligodontia or complete anodontia, conical teeth, underdeveloped alveolar ridges, generalized spacing and delayed eruption of permanent teeth. This case report discusses a classical case of HED and the options for rehabilitation in a growing patient. A thorough knowledge about the clinical manifestations of ED will lead to proper diagnosis and appropriate treatment plan thereby leading to significant improvements in esthetics, phonetics and masticatory function in ED patients, which in turn leads to improved quality of life in these individuals.

Genetic Hair Disorders: A Review

Hair loss in early childhood represents a broad differential diagnosis which can be a diagnostic and therapeutic challenge for a physician. It is important to consider the diagnosis of a genetic hair disorder. Genetic hair disorders are a large group of inherited disorders, many of which are rare. Genetic hair abnormalities in children can be an isolated phenomenon or part of genetic syndromes. Hair changes may be a significant finding or even the initial presentation of a syndrome giving a clue to the diagnosis, such as Netherton syndrome and trichothiodystrophy. Detailed history including family history and physical examination of hair and other ectodermal structures such as nails, sweat glands, and sebaceous glands with the use of dermoscopic devices and biopsy all provide important clues to establish the correct diagnosis. Understanding the pathophysiology of genetic hair defects will allow for better comprehension of their treatment and prognosis. For example, in patients with an isolated hair defect, the main problem is aesthetic. In contrast, when the hair defect is associated with a syndrome, the prognosis will depend mainly on the associated condition. Treatment of many genetic hair disorders is focused on treating the primary cause and minimizing trauma to the hair.

[Dental-craniofacial manifestation and treatment of rare diseases in China]

Rare diseases are genetic, chronic, and incurable disorders with relatively low prevalence. Thus, diagnosis and management strategies for such diseases are currently limited. This situation is exacerbated by insufficient medical sources for these diseases. The National Health and Health Committee of China recently first provided a clear definition of 121 rare diseases in the Chinese population. In this study, we summarize several dental-craniofacial manifestations associated with some rare diseases to provide a reference for dentists and oral maxillofacial surgeons aiming at fast-tracking diagnosis for the management of these rare diseases.

Dental-craniofacial manifestation and treatment of rare diseases

Rare diseases are usually genetic, chronic and incurable disorders with a relatively low incidence. Developments in the diagnosis and management of rare diseases have been relatively slow due to a lack of sufficient profit motivation and market to attract research by companies. However, due to the attention of government and society as well as economic development, rare diseases have been gradually become an increasing concern. As several dental-craniofacial manifestations are associated with rare diseases, we summarize them in this study to help dentists and oral maxillofacial surgeons provide an early diagnosis and subsequent management for patients with these rare diseases.

Reliability of prenatal detection of X-linked hypohidrotic ectodermal dysplasia by tooth germ sonography

OBJECTIVE

In X-linked hypohidrotic ectodermal dysplasia (XLHED), dysfunction of ectodysplasin A1 (EDA1) due to EDA mutations results in malformation of hair, teeth, and sweat glands. Hypohidrosis, which can cause life-threatening hyperthermia, is amenable to intrauterine therapy with recombinant EDA1. This study aimed at evaluating tooth germ sonography as a noninvasive means to identify affected fetuses in pregnant carrier women.

METHODS

Sonography, performed at 10 study sites between gestational weeks 18 and 28, led to the diagnosis of XLHED if fewer than six tooth germs were detected in mandible or maxilla. The assessment was verified postnatally by EDA sequencing and/or clinical findings. Estimated fetal weights and postnatal weight gain of boys with XLHED were assessed using appropriate growth charts.

RESULTS

In 19 of 38 sonographic examinations (23 male and 13 female fetuses), XLHED was detected prenatally. The prenatal diagnosis proved to be correct in 37 cases; one affected male fetus was missed. Specificity and positive predictive value were both 100%. Tooth counts obtained by clinical examination corresponded well with findings on panoramic radiographs. We observed no weight deficits of subjects with XLHED in utero but occasionally during infancy.

CONCLUSION

Tooth germ sonography is highly specific and reliable in detecting XLHED prenatally.

An ectodermal dysplasia patient treated with a small diameter implant supporting a single crown

Ectodermal dysplasia (EDD) is a developmental disorder that affects the skin, hair, and teeth among other organs generated in the ectoderm. Dental implants have been used to successfully treat partial edentulism in EDD patients, but the success rate is much lower for these patients. The report herein is a successful case of a single mini, small diameter, implant used to support a single crown of a mandibular right second premolar. A review of implant treatment in EDD patients is included.

Mesiodistal and Buccolingual Dimensions in Croatian Orthodontic Hypodontia Patients' Teeth

OBJECTIVE

This study compared mesiodistal (MD) and buccolingual (BL) tooth dimensions of hypodontia patients with a control group with complete dentition. The null hypothesis was that there was no difference in tooth sizes between hypodontia patients and the controls.

METHODS

The sample comprised 76 patients with hypodontia (50 female and 26 male) aged between 11 and 18 years. The control group comprised 50 females and 26 males with the same age range as the study group. Mesiodistal (MD) and buccolingual (BL) dimensions were measured on pretreatment dental casts with a digital caliper to the nearest 0.01 mm. The data were analyzed using Statistica 7.1 (StatSoft Inc.) statistical package (descriptive statistics, test of distribution normality, parametric statistics).

RESULTS

The most common congenitally missing teeth were the lower second premolars (left 13.45% and right 13.90%) and upper lateral incisors (both left and right 12.56%), followed by upper second premolars (right 9.4o% and left 10.31%). The greatest differences between the study and control group were found in upper lateral incisors, 8.08% in MD and 6.40% in BL dimension. The smallest difference was found in BL dimension of lower lateral incisor (2.37%), MD dimension of lower second premolars and upper first molar (2.61%) and MD dimension of lower central incisor (2.26%).

CONCLUSION

The teeth are smaller in subjects with hypodontia than those of the controls on average 4.02% in MD dimension and 3.85% in BL dimension. The tooth that showed the greatest difference in tooth dimension was maxillary lateral incisor.

The Impact of the Eda Pathway on Tooth Root Development

The Eda pathway ( Eda, Edar, Edaradd) plays an important role in tooth development, determining tooth number, crown shape, and enamel formation. Here we show that the Eda pathway also plays a key role in root development. Edar (the receptor) is expressed in Hertwig's epithelial root sheath (HERS) during root development, with mutant mice showing a high incidence of taurodontism: large pulp chambers lacking or showing delayed bifurcation or trifurcation of the roots. The mouse upper second molars in the Eda pathway mutants show the highest incidence of taurodontism, this enhanced susceptibility being matched in human patients with mutations in EDA-A1. These taurodont teeth form due to defects in the direction of extension of the HERS from the crown, associated with a more extensive area of proliferation of the neighboring root mesenchyme. In those teeth where the angle at which the HERS extends from the crown is very wide and therefore more vertical, the mutant HERSs fail to reach toward the center of the tooth in the normal furcation region, and taurodont teeth are created. The phenotype is variable, however, with milder changes in angle and proliferation leading to normal or delayed furcation. This is the first analysis of the role of Eda in the root, showing a direct role for this pathway during postnatal mouse development, and it suggests that changes in proliferation and angle of HERS may underlie taurodontism in a range of syndromes.

Abnormal primary and permanent dentitions with ectodermal symptoms predict WNT10A deficiency

BACKGROUND

The WNT10A protein is critical for the development of ectodermal appendages. Variants in the WNT10A gene may be associated with a spectrum of ectodermal abnormalities including extensive tooth agenesis.

METHODS

In seven patients with severe tooth agenesis we identified anomalies in primary dentition and additional ectodermal symptoms, and assessed WNT10A mutations by genetic analysis.

RESULTS

Investigation of primary dentition revealed peg-shaped crowns of primary mandibular incisors and three individuals had agenesis of at least two primary teeth. The permanent dentition was severely affected in all individuals with a mean of 21 missing teeth. Primary teeth were most often present in positions were succedaneous teeth were missing. Furthermore, most existing molars had taurodontism. Light, brittle or coarse hair was reported in all seven individuals, hyperhidrosis of palms and soles in six individuals and nail anomalies in two individuals. The anomalies in primary dentition preceded most of the additional ectodermal symptoms. Genetic analysis revealed that all seven individuals were homozygous or compound heterozygous for WNT10A mutations resulting in C107X, E222X and F228I.

CONCLUSIONS

We conclude that tooth agenesis and/or peg-shaped crowns of primary mandibular incisors, severe oligodontia of permanent dentition as well as ectodermal symptoms of varying severity may be predictors of bi-allelic WNT10A mutations of importance for diagnosis, counselling and follow-up.

Ectodermal Dysplasia: A Clinical Overview for the Dental Practitioner

The term ectodermal dysplasia (ED) is used to describe a group of rare congenital disorders characterized by abnormalities of two or more ectodermal structures such as the skin, hair, nails, teeth and sweat glands. This paper will give an overview of the aetiology of ED and describe the manifestations and dental management of this condition. In particular, the important role of the dental practitioner in the identification and management of patients with ED will be highlighted. CPD/Clinical Relevance: Dental practitioners should be aware of the oral features of ectodermal dysplasia and be able to make timely referrals and provide appropriate continuing care for these patients.

Age estimation by dental developmental stages in children and adolescents in Iceland

Studies have shown that it is necessary to create a database for dental maturity for every population and compare it to others. The present study is the first one for dental development in the Icelandic population the age range being 4-24 years. It will help in forensic dental age estimation and will also help dentists, physicians, anthropologists, archaeologists and other professionals who rely on developmental age assessment in children and adolescents. In this present retrospective cross-sectional study, dental maturity was determined in 1100 Icelandic children and adolescents from orthopantomograms (OPGs). The first 100 were used for a pilot study and the remaining 1000 for the main study. A total of 23 subjects were excluded. The sample consisted of 508 girls and 469 boys from the age of 4-24 years and a dental developmental scoring system was used as a standard for determination of dental maturity stages. A total of 200 OPGs were studied both on the left and right side and the remaining on the right side. Dental maturity was established for all teeth and both genders, when the sample permitted, from the beginning of crown formation to the root apex closure. The Cronbach's Alpha reliability test showed high reliability, R=0.982. Girls in Iceland reach dental maturity root completed (stage 10, Rc) at 17.81 years of age for the maxillary and at 18.47 years for the mandibular teeth. Boys reach dental maturity root completed (stage 10, Rc) at 18.00 years of age in the maxilla and 17.63 in the mandible. There was no significant difference between left and right side (r=0.95-1.00) and there was no gender difference, except in root formation in maxillary and mandibular canines where girls reached root completed earlier than boys. A reliable database has been established in Iceland for tooth development in the age range of 4-24 years, which is compatible with international studies. These results will help forensic odontologists and other professionals to estimate with high accuracy both age and dental maturity in Icelandic children and adolescents.

From Bench to Bedside and Back: Improving Diagnosis and Treatment of Craniofacial Malformations Utilizing Animal Models

Craniofacial anomalies are among the most common birth defects and are associated with increased mortality and, in many cases, the need for lifelong treatment. Over the past few decades, dramatic advances in the surgical and medical care of these patients have led to marked improvements in patient outcomes. However, none of the treatments currently in clinical use address the underlying molecular causes of these disorders. Fortunately, the field of craniofacial developmental biology provides a strong foundation for improved diagnosis and for therapies that target the genetic causes of birth defects. In this chapter, we discuss recent advances in our understanding of the embryology of craniofacial conditions, and we focus on the use of animal models to guide rational therapies anchored in genetics and biochemistry.

An evaluation of clinical, radiological and three-dimensional dental tomography findings in ectodermal dysplasia cases

BACKGROUND

This study aimed to review the results related to head and jaw disorders in cases of ectodermal dysplasia. The evaluation of ectodermal dysplasia cases was made by clinical examination and examination of the jaw and facial areas radiologically and on cone-beam 3-dimensional dental tomography (CBCT) images.

MATERIAL AND METHODS

In the 36 cases evaluated in the study, typical clinical findings of pure hypohidrotic ectodermal displasia (HED) were seen, such as missing teeth, dry skin, hair and nail disorders. CBCT images were obtained from 12 of the 36 cases, aged 1.5- 45 years, and orthodontic analyses were made on these images.

RESULTS

The clinical and radiological evaluations determined, hypodontia or oligodontia, breathing problems, sweating problems, a history of fever, sparse hair, saddle nose, skin peeling, hypopigmentation, hyperpigmentation, finger and nail deformities, conical teeth anomalies, abnormal tooth root formation, tooth resorption in the root, gingivitis, history of epilepsy, absent lachrymal canals and vision problems in the cases which included to the study.

CONCLUSIONS

Ectodermal dysplasia cases have a particular place in dentistry and require a professional, multi-disciplinary approach in respect of the chewing function, orthognathic problems, growth, oral and dental health. It has been understood that with data obtained from modern technologies such as three-dimensional dental tomography and the treatments applied, the quality of life of these cases can be improved.

Dentomaxillofacial characteristics of ectodermal dysplasia

The aim of this retrospective hospital-based study was to elucidate the dentomaxillofacial characteristics of ectodermal dysplasia. Six Japanese individuals (one male and five female; age range, 12.7-27.2 years) underwent comprehensive examinations, including history recording, cephalometric analysis, panoramic radiography, and analysis of dental models. All the subjects had two or more major manifestations for clinical diagnosis of ectodermal dysplasia (e.g., defects of hair, teeth, nails, and sweat glands). They presented hypodontia (mean number of missing teeth, 9.5; range, 5-14), especially in the premolar region, and enamel dysplasia. Five subjects had bilateral molar occlusion, whereas one subject had unilateral molar occlusion. The common skeletal features were small facial height, maxillary hypoplasia, counterclockwise rotation of the mandible, and mandibular protrusion. Interestingly, the maxillary first molars were located in higher positions and the upper anterior facial height was smaller than the Japanese norm. The results suggest that vertical and anteroposterior maxillary growth retardation, rather than lack of occlusal support due to hypodontia, leads to reduced anterior facial height in individuals with ectodermal dysplasia.

Clinical and genetic analysis of a nonsyndromic oligodontia in a child

The etiology of tooth agenesis may be related to several factors, among them, the genetic alterations that play a fundamental role in the development of this dental anomaly, so that knowledge about it helps the clinician to have a greater understanding of their patients. Thus, the aim of this study was to report the case of a nonsyndromic child, with tooth agenesis of one premolar, three first permanent molars, and all second permanent molars. In addition, a genetic research between polymorphic variants in genes MMP3 and BMP2 was performed in order to observe the association between changes in these genes and congenital tooth absences. For this purpose, DNA from child was extracted and polymorphisms were investigated. It was clinically and radiographically observed that this was a case of oligodontia, in which the authors suggested an association between the polymorphisms found and tooth agenesis diagnosed in that child.

Phenotypic heterogeneity and mutational spectrum in a cohort of 45 Italian males subjects with X-linked ectodermal dysplasia

Ectodermal dysplasias (EDs) are a group of genetic disorders characterized by the abnormal development of the ectodermal-derived structures. X-linked hypohidrotic ectodermal dysplasia, resulting from mutations in ED1 gene, is the most common form. The main purpose of this study was to characterize the phenotype spectrum in 45 males harboring ED1 mutations. The study showed that in addition to the involvement of the major ectodermal tissues, the majority of patients also have alterations of several minor ectodermal-derived structures. Characterizing the clinical spectrum resulting from ED1 gene mutations improves diagnosis and can direct clinical care.

Orodental manifestations in ectodermal dysplasia-a review

Oral signs and symptoms are present in most ectodermal dysplasias (EDs). The aim of this article is to summarize some of the literature on current knowledge of oral manifestations and orofacial function in EDs. The review will focus on the most common forms where dental manifestations can be crucial for a differential diagnosis of ED among individuals with hypodontia and oligodontia, and preferably where the investigations included persons who had a genetically verified diagnosis. Disturbances in tooth development are common and can appear as tooth agenesis, variations in size and shape of teeth, defects in the mineralized tissues, and problems in tooth eruption. Abnormalities in number, size, and shape of teeth, and reduced salivary secretion, present in isolated oligodontia as well as in hypohidrotic ED and incontinentia pigmenti. In some more rare EDs these symptoms appear in combination with clefts of lip and/or palate in some affected individuals. Leukokeratosis in the oral mucosa presents in 70% of genetically confirmed cases of pachyonychia congenita. Also, orofacial function is often affected in ED, due to malformations, an incomplete dentition, and low salivary secretion which can compromise chewing, swallowing, and speech. In conclusion, there is a clinical overlap in oral signs and symptoms between isolated oligodontia and the most common EDs. Studies with genetically confirmed diagnoses and larger cohorts, as well as multicenter collaboration and the establishing of international registries, would create a basis for refined diagnostics, where oral examinations should be an integrated part of clinical assessment.

The WNT10A gene in ectodermal dysplasias and selective tooth agenesis

Mutations in the WNT10A gene were first detected in the rare syndrome odonto-onycho-dermal dysplasia (OODD, OMIM257980) but have now also been found to cause about 35-50% of selective tooth agenesis (STHAG4, OMIM150400), a common disorder that mostly affects the permanent dentition. In our random sample of tooth agenesis patients, 40% had at least one mutation in the WNT10A gene. The WNT10A Phe228Ile variant alone reached an allele frequency of 0.21 in the tooth agenesis cohort, about 10 times higher than the allele frequency reported in large SNP databases for Caucasian populations. Patients with bi-allelic WNT10A mutations have severe tooth agenesis while heterozygous individuals are either unaffected or have a mild phenotype. Mutations in the coding areas of the WNT10B gene, which is co-expressed with WNT10A during odontogenesis, and the WNT6 gene which is located at the same chromosomal locus as WNT10A in humans, do not contribute to the tooth agenesis phenotype.

X-linked hypohidrotic ectodermal dysplasia (XLHED): clinical and diagnostic insights from an international patient registry

The web-based Ectodermal Dysplasia International Registry (EDIR) is a comprehensive patient-reported survey contributing to an understanding of ectodermal dysplasia (ED). XLHED is the most common of the genetic ED syndromes and was the primary diagnosis reported by 223/835 respondents (141 males and 82 females). Overall, 96% of XLHED registrants reported as least one other affected family member and 21% reported a family history of infant or childhood deaths, consistent with the published mortality data in this disorder. In general, XLHED is diagnosed by the triad of decreased sweating, reduced hair, and hypodontia (present in 89%, 74%, and 74% of XLHED respondents). Additionally, the registry dataset confirmed a spectrum of life-long XLHED clinical complications including recurrent sinus infections (49% males, 52% females), nasal congestion often foul smelling and interfering with feeding (73% males, 27% females), eczema (66% males, 40% females), wheezing (66% males, 45% females), and a hoarse, raspy voice (67% males, 23% females). The Registry results also highlighted features consistently differentiating XLHED from the non-hypohidrotic ED syndromes including the frequency of infant/childhood deaths, the presence of limb/digit abnormalities, feeding issues related to nasal discharge, dentures, and a diagnosis of asthma. These results represent the largest collection of data on a broad-spectrum of health-related issues affecting ED patients. This project provides information for expanding knowledge of the natural history of XLHED, and as such may facilitate the diagnosis and treatment of its varied and lifelong medical challenges.

Hypohidrotic Ectodermal Dysplasia (ED): A Case Series

ECTODERMAL DYSPLASIA (ED) IS A RARE DISORDER WITH DEFECTS IN TWO OR MORE OF THE FOLLOWING STRUCTURES: the teeth and the skin and its appendages including hair, nails, eccrine, and sebaceous glands. Dental manifestations include hypodontia, complete anodontia or malformed teeth. The most common form of the ED syndrome is hypohidrotic ED and is usually inherited as an X-linked recessive trait. Female carriers may have a variable degree of clinical manifestations. The condition is thought to occur in approximately 1 in every 100,000 live births. Dental treatment for these patients varies on an individual basis. Children with ED are often treated dentally with conventional adult appearing prosthesis which are focused only on the oral manifestations of the syndrome. We are here reporting two classical cases of hypohidrotic ED with a review of the literature.

Candidate gene analysis of tooth agenesis identifies novel mutations in six genes and suggests significant role for WNT and EDA signaling and allele combinations

Failure to develop complete dentition, tooth agenesis, is a common developmental anomaly manifested most often as isolated but also as associated with many developmental syndromes. It typically affects third molars or one or few other permanent teeth but severe agenesis is also relatively prevalent. Here we report mutational analyses of seven candidate genes in a cohort of 127 probands with non-syndromic tooth agenesis. 82 lacked more than five permanent teeth excluding third molars, called as oligodontia. We identified 28 mutations, 17 of which were novel. Together with our previous reports, we have identified two mutations in MSX1, AXIN2 and EDARADD, five in PAX9, four in EDA and EDAR, and nine in WNT10A. They were observed in 58 probands (44%), with a mean number of missing teeth of 11.7 (range 4 to 34). Almost all of these probands had severe agenesis. Only few of the probands but several relatives with heterozygous genotypes of WNT10A or EDAR conformed to the common type of non-syndromic tooth agenesis, incisor-premolar hypodontia. Mutations in MSX1 and PAX9 affected predominantly posterior teeth, whereas both deciduous and permanent incisors were especially sensitive to mutations in EDA and EDAR. Many mutations in EDAR, EDARADD and WNT10A were present in several families. Biallelic or heterozygous genotypes of WNT10A were observed in 32 and hemizygous or heterozygous genotypes of EDA, EDAR or EDARADD in 22 probands. An EDARADD variant were in seven probands present together with variants in EDAR or WNT10A, suggesting combined phenotypic effects of alleles in distinct genes.

Existing data sources for clinical epidemiology: Danish registries for studies of medical genetic diseases

Denmark has an extensive collection of national and regional medical registries. There are many advantages to registry-based research when investigating genetic diseases which, due to their rarity, can be difficult to identify. In this study, we aimed to provide an updated overview of Danish registries for medical genetic conditions and describe how data linkage across registries can be used to collect data on genetic diseases at the individual level and at the family level. We present a list of medical genetic registries in Denmark at the national level, data sources from the departments of clinical genetics and other specialized centers, and project-specific data sources. We also summarize key general registries, such as the Danish National Registry of Patients, the Danish Medical Birth Registry, and the Civil Registration System, which are renowned for their comprehensive and high quality data, and are useful supplemental data sources for genetic epidemiology research. We describe the potential for data linkage across multiple registries, which allows for access to medical histories with follow-up time spanning birth to death. Finally, we provide a brief introduction to the Danish epidemiological research setting and legalities related to data access. The Danish collection of medical registries is a valuable resource for genetic epidemiology research.

Evaluation of tooth size in patients with congenitally-missing teeth

Background and aims

Hypodontia is a common developmental abnormality of dentition. This study aimed to determine tooth width in patients affected with mild hypodontia and compare the results with a control group without tooth agenesis.

Materials and methods

The orthodontic records of 25 patients with congenital missing of one or two teeth (hypodontia group), and 25 subjects with full dentition (control group) were selected. The greatest mesiodistal width of each tooth was measured on the study models by a digital caliper. Tooth width measurements were compared between the groups using a student t-test at p < 0.05 of significance.

Results

Patients with hypodontia showed narrower teeth than the control subjects. The differences in tooth size between the two groups were statistically significant for the first and second premolars and first molar in the maxillary right and for the second premolar in the maxillary left quadrants (p < 0.05). In the lower arch, the first and second premolars and also first molar in both sides of hypodontia patients demonstrated significant reduction in tooth size compared to the control group (p < 0.05).

Conclusion

These findings suggest that patients with mild hypodontia have narrower teeth than normal subjects especially in posterior segments, which may have clinical implications during the orthodontic treatment process.

Christ-siemens-touraine syndrome: a case report and review of the literature

Ectodermal dysplasia is a rare disorder with defects in two or more of the following structures: the teeth and the skin and its appendages including hair, nails, eccrine, and sebaceous glands. Anhidrotic ectodermal dysplasia is the most common type of disease. This rare disorder, also known as Christ-Siemens-Touraine syndrome, manifests as a triad of hypotrichosis, asteatosis, and anhidrosis. In view of the rarity of this entity, a classical case of anhidrotic ectodermal dysplasia is reported. We have also provided a review of recent investigations in the area of dental abnormalities in this syndrome.

Orofacial dysfunction in ectodermal dysplasias measured using the Nordic Orofacial Test-Screening protocol

OBJECTIVE

To screen orofacial function in people with various ectodermal dysplasia (ED) syndromes and compare with a healthy reference sample.

MATERIAL AND METHODS

The ED group comprised 46 individuals (30 M and 16 F; mean age 14.5 years, range 3-55). Thirty-two had hypohidrotic ED, while 14 had other ED syndromes. The reference sample comprised 52 healthy individuals (22 M and 30 F; mean age 24.9 years, range 3-55). Orofacial function was screened using the Nordic Orofacial Test-Screening (NOT-S) protocol containing 12 orofacial function domains (maximum score 12 points).

RESULTS

The total NOT-S score was higher in the ED group than in the healthy group (mean 3.5 vs. 0.4; p<0.001). The dysfunctions most frequently recorded in the subjects with ED occurred in the domains chewing and swallowing (82.6%), dryness of the mouth (45.7%), and speech (43.5%). Those with other ED syndromes scored non-significantly higher than those with hypohidrotic ED (mean 4.6 vs. 3.0; p>0.05).

CONCLUSIONS

Individuals with ED scored higher than a healthy reference sample in all NOT-S domains, especially in the chewing and swallowing, dryness of the mouth, and speech domains. Orofacial function areas and treatment and training outcomes need to be more closely evaluated and monitored.

Three-dimensional analysis of tooth dimensions in the MSX1-missense mutation

OBJECTIVES

A novel, 3D technique to measure the differences in tooth crown morphology between the MSX1 cases and non-affected controls was designed to get a better understanding of dental phenotype-genotype associations.

MATERIALS AND METHODS

Eight Dutch subjects from a single family with tooth agenesis, all with an established nonsense mutation c.332 C > A, p. Ser 111 Stop in exon 1 of MSX1, were compared with unaffected controls regarding several aspects of tooth crown morphology of incisor and molar teeth. A novel method of quantitative three-dimensional analysis was used to detect differences.

RESULTS

Statistically significant shape differences were observed for the maxillary incisor in the MSX1 family compared with the controls on the following parameters: surface area, buccolingual dimension, squareness, and crown volume (P ≤ 0.002). Molar crown shape was unaffected.

CONCLUSIONS

A better understanding of dental phenotype-genotype associations may contribute to earlier diagnosis of some multiple-anomaly congenital syndromes involving dental anomalies.

CLINICAL RELEVANCE

A "shape database" that includes associated gene mutations resulting from developmental syndromes may facilitate the genetic identification of hypodontia cases.

Oral rehabilitation of children with ectodermal dysplasia

The aim of this study was to describe the clinical treatment of young patients, affected by ectodermal dysplasia (ED), and to possibly establish clinical guidelines. The study design was case series. ED syndromes (EDs) are a heterogeneous group of inherited diseases characterised by abnormal development of tissues of ectodermal origin. The most common form of EDs is X linked hypohidrotic ED (HED). Characteristic triad of HED is oligo-anodontia, hypotricosis, hypo-anhydrosis. Oligo-anodontia is one of the most severe impairment, since it affects chewing, swallowing, speech, esthetics and social relation. Early prosthetic rehabilitation (at 2-3 years of age), with partial or complete dentures, is essential to improve oral function and reduce the social impairment.

Oral rehabilitation of a young patient with hypohidrotic ectodermal dysplasia: A clinical report

Ectodermal dysplasia (ED) represents a group of patients with mild to severe congenital and developmental anomalies. Dentists are the first person to identify ED in young patients. The impairment is not just the form and function but extends to the social outlook as well as the psychology of the affected individual. This case report describes management of ED with a long-span fixed partial denture fabricated using a Broadrick flag.

Orofacial features of hypohidrotic ectodermal dysplasia

Hypohidrotic ectodermal dysplasia (HED) is a type of genodermatosis characterized by the abnormal development of sweat glands, teeth, and hair. The most prevalent form of HED is X-linked hypohidrotic ectodermal dysplasia (XLHED), which is associated with mutations in the EDA gene. The aim of this case report was to describe a family with XLHED with emphasis on differences in orofacial features between members. Family members were systematically evaluated to characterize the pattern of inheritance and clinical features. Dental examination included evaluation of agenesis and abnormal teeth structure. The pedigree of the last seven generations of the family was constructed. Clinical examination and medical history revealed five males affected by HED and nine female as heterozygous carriers. The males exhibited the classic phenotype of XLHED, with dental abnormalities, hypohydrosis, and craniofacial dysmorphologies. The heterozygous carriers of the X-linked gene defect principally exhibited dental agenesis of the lateral maxillary incisors. Careful clinical examination, including dental evaluation, is an important way to detect heterozygous carriers of X-linked HED. Heterozygous parents of patients with HED may also show some features of the disorder. The identification of female carriers results in genetic counseling being offered to affected families, as well as providing adequate treatment as necessary and long-term follow-up of these patients.

Surgical and implant-supported fixed prosthetic treatment of a patient with ectodermal dysplasia: a case report

Ectodermal dysplasia (ED) is a hereditary disorder that affects ectodermal structures. The main clinical oral manifestations of ED include oligodontia and deficient alveolar ridges. This case report presents the oral rehabilitation of a 15-year-old female patient who never received an accurate diagnosis or appropriate dental care. Treatment included a combination of surgical intervention, a maxillary tooth-supported fixed detachable telescopic prosthesis, and an implant-supported mandibular fixed partial denture. The results showed a significant improvement in the esthetics, function, and psychological status of the patient. This article stresses the importance of appropriate care in providing an acceptable quality of life for patients with ED.

The potential investment impact of improved access to accelerated approval on the development of treatments for low prevalence rare diseases

BACKGROUND

Over 95% of rare diseases lack treatments despite many successful treatment studies in animal models. To improve access to treatments, the Accelerated Approval (AA) regulations were implemented allowing the use of surrogate endpoints to achieve drug approval and accelerate development of life-saving therapies. Many rare diseases have not utilized AA due to the difficulty in gaining acceptance of novel surrogate endpoints in untreated rare diseases.

METHODS

To assess the potential impact of improved AA accessibility, we devised clinical development programs using proposed clinical or surrogate endpoints for fifteen rare disease treatments.

RESULTS

We demonstrate that better AA access could reduce development costs by approximately 60%, increase investment value, and foster development of three times as many rare disease drugs for the same investment.

CONCLUSION

Our research brings attention to the need for well-defined and practical qualification criteria for the use of surrogate endpoints to allow more access to the AA approval pathway in clinical trials for rare diseases.

Dental abnormalities associated with X-linked hypohidrotic ectodermal dysplasia in dogs

OBJECTIVES

X-linked hypohidrotic ectodermal dysplasia (XLHED) occurs in several species, including humans, mice, cattle and dogs. The orofacial manifestations of ectodermal dysplasia in humans and mice have been extensively studied, but documentation of dental abnormalities in dogs is lacking. The current study describes the results of clinical and radiographic examinations of XLHED-affected dogs and demonstrates profound similarities to findings of XLHED-affected humans.

SETTING AND SAMPLE POPULATION

Section of Medical Genetics at the University of Pennsylvania, School of Veterinary Medicine. Clinical and radiographic oral examinations were performed on 17 dogs with XLHED, three normal dogs, and two dogs heterozygous for XLHED.

MATERIALS AND METHODS

The prevalence and severity of orofacial and dental abnormalities were evaluated by means of a sedated examination, photographs, and full-mouth intraoral radiographs.

RESULTS

Crown and root abnormalities were common in dogs affected by XLHED, including hypodontia, oligodontia, conical crown shape, decreased number of cusps, decreased number of roots, and dilacerated roots. Persistent deciduous teeth were frequently encountered. Malocclusion was common, with Angle Class I mesioversion of the maxillary and/or mandibular canine teeth noted in 15 of 17 dogs. Angle Class III malocclusion (maxillary brachygnathism) was seen in one affected dog.

CONCLUSION

Dental abnormalities are common and severe in dogs with XLHED. Dental manifestations of canine XLHED share characteristics of brachyodont tooth type and diphyodont dentition, confirming this species to be an orthologous animal model for study of human disease.