KBG syndrome in a Chinese population: A case series

KBG syndrome (OMIM #148050) is an autosomal dominant neurodevelopmental disorder characterized by the presence of macrodontia of the permanent central upper incisors, characteristic facial features, delay in development, intellectual disability, short stature, and various skeletal abnormalities. Over 200 affected individuals have been described worldwide, though underdiagnosis is suspected because the characteristic features are variably present and affected individuals can have a mild phenotype. This case series provides a summary of the clinical and molecular characteristics of 10 Chinese KBG syndrome patients recruited from a single center. To our knowledge, this is the first case series for Chinese KBG patients. This case series aimed at exploring potential ethnicity-related variability in KBG syndrome.

Is there any relationship between hypodontia and hyperdontia with taurodontism, microdontia and macrodontia? A retrospective study

Background

Hypodontia and hyperdontia may occur with other dental anomalies such as microdontia, taurodontism, talon cusp, macrodontia and germination.

Aims

The aim of this study to evaluate the relationship between hypodontia and hyperdontia with taurodontism, macrodontia and microdontia.

Subjects and Methods

In this retrospective study, 2,348 Turkish patients aged 7 to 12 years and treated between 01.01.2017 and 01.01.2018 in Bahcelievler Oral and Dental Health Hospital were evaluated. Data were collected and differences in the distribution of hypodontia and hyperdontia including other dental anomalies were analysed.

Results

Of the total sample of 2,348 patients, 1,126 (48%) were girls, 1,222 (52%) were boys. Hypodontia was found in 177 children (93 girls (53%), 84 boys (47%)). The prevalence of hypodontia and hyperdontia were 7.5% and 0.9%. Taurodontism is the most common dental anomalies in hypodontia patients (39%) followed by microdontia (10%). Taurodontism was more prevalent in girls (42%) than in boys (36.5%). Microdontia was found in 10 patients and macrodontia was observed in 9 hypodontia patients. Hyperdontia was found in 21 children [8 girls (38%), 13 boys (62%)]. The most common supernumerary tooth found was mesiodens (85%) and it's more prevalent in boys (67%) than in girls (33%). Taurodontism is the most common dental anomaly (48%) following macrodontia (19%) and were found to be much more prevalent in boys (53%) (23%) than in girls (37.5%) (12.5%). Microdontia was found in only 1 boy (%7.7) in hyperdontia patients.

Conclusion

Hypodontia and hyperdontia with taurodontism, microdontia, and macrodontia need much more complex treatment plan. All cases should be evaluated using interdisciplinary approach for appropriate treatment choice. This helps in longterm and effective treatment planning according to a child's individual requirements.

KBG syndrome in two patients from Egypt

KBG syndrome is an intellectual disability (ID) associated with multiple congenital anomalies in which the macrodontia could be the clue for the diagnosis. It is caused either by heterozygous variant in ANKRD11 gene or 16q24.3 microdeletions that involve the ANKRD11 gene. Here, we report on two unrelated male patients who presented with ID, short stature, webbing of neck, and cryptorchidism. Noonan syndrome was suspected first but the presence of macrodontia in both patients pointed to KBG syndrome which was confirmed thereafter by the identification of a novel pathogenic variant in ANKRD11 gene, c.5488G>T (p.E1830*). Macrodontia was noticed in all the deciduous anterior teeth in Patient 1. This observation was reported previously in few patients, but it seems to be a common feature that could be misdiagnosed as premature eruption of teeth. Therefore, our results confirm that maxillary permanent central incisors may not be the only teeth affected in KBG but also all the deciduous teeth. Interestingly, desquamative gingivitis was additionally noted in Patient 1, which has not been reported previously, however; it could be a coincidental finding. To the best of our knowledge, this is the first report from Egypt.

KBG syndrome: Common and uncommon clinical features based on 31 new patients

KBG syndrome (MIM #148050) is an autosomal dominant disorder characterized by developmental delay, intellectual disability, distinct craniofacial anomalies, macrodontia of permanent upper central incisors, skeletal abnormalities, and short stature. This study describes clinical features of 28 patients, confirmed by molecular testing of ANKRD11 gene, and three patients with 16q24 deletion encompassing ANKRD11 gene, diagnosed in a single center. Common clinical features are reported, together with uncommon findings, clinical expression in the first years of age, distinctive associations, and familial recurrences. Unusual manifestations emerging from present series include juvenile idiopathic arthritis, dysfunctional dysphonia, multiple dental agenesis, idiopathic precocious telarche, oral frenula, motor tics, and lipoma of corpus callosum, pilomatrixoma, and endothelial corneal polymorphic dystrophy. Facial clinical markers suggesting KBG syndrome before 6 years of age include ocular and mouth conformation, wide eyebrows, synophrys, long black eyelashes, long philtrum, thin upper lip. General clinical symptoms leading to early genetic evaluation include developmental delay, congenital malformations, hearing anomalies, and feeding difficulties. It is likely that atypical clinical presentation and overlapping features in patients with multiple variants are responsible for underdiagnosis in KBG syndrome. Improved knowledge of common and atypical features of this disorder improves clinical management.

A case of multiple dental anomalies: a variant of Ekman-Westborg-Julin trait

Simultaneous occurrence of multiple dental anomalies is relatively common and has been reported particularly in cases with systemic alterations or syndromes. However, in 1974, Ekman-Westborg and Julin described a unique case of multiple macrodontia and multituberculism of posterior teeth accompanied by multiple dental malformations without other systemic anomalies. Here we report the case of a 20-year-old female patient who presented with macrodontia affecting her maxillary lateral teeth, mandibular incisors, and impacted multituberculated wisdom teeth accompanied by other dental anomalies that manifested itself as a variant of the Ekman-Westborg–Julin trait.

Clinical and genetic aspects of KBG syndrome

KBG syndrome is characterized by short stature, distinctive facial features, and developmental/cognitive delay and is caused by mutations in ANKRD11, one of the ankyrin repeat-containing cofactors. We describe 32 KBG patients aged 2-47 years from 27 families ascertained via two pathways: targeted ANKRD11 sequencing (TS) in a group who had a clinical diagnosis of KBG and whole exome sequencing (ES) in a second group in whom the diagnosis was unknown. Speech delay and learning difficulties were almost universal and variable behavioral problems frequent. Macrodontia of permanent upper central incisors was seen in 85%. Other clinical features included short stature, conductive hearing loss, recurrent middle ear infection, palatal abnormalities, and feeding difficulties. We recognized a new feature of a wide anterior fontanelle with delayed closure in 22%. The subtle facial features of KBG syndrome were recognizable in half the patients. We identified 20 ANKRD11 mutations (18 novel: all truncating) confirmed by Sanger sequencing in 32 patients. Comparison of the two ascertainment groups demonstrated that facial/other typical features were more subtle in the ES group. There were no conclusive phenotype-genotype correlations. Our findings suggest that mutation of ANKRD11 is a common Mendelian cause of developmental delay. Affected patients may not show the characteristic KBG phenotype and the diagnosis is therefore easily missed. We propose updated diagnostic criteria/clinical recommendations for KBG syndrome and suggest that inclusion of ANKRD11 will increase the utility of gene panels designed to investigate developmental delay. © 2016 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.

Fused teeth, macrodontia and increased caries are characteristic features of neurofibromatosis type 1 patients with NF1 gene microdeletion

Neurofibromatosis type 1 (NF1) is the most common genetic condition caused by NF1 gene alteration. A 1.5 Mb submicroscopic deletion encompassing the entire NF1 gene, is known to be responsible for approximately 5% of NF1 cases. Patients with NF1 deletion, compared to those with NF1 mutation tend to exhibit more severe phenotypes. To know the possible differences in oral/dental features between NF1 deletion and NF1 mutation patients, we examined four patients with NF1 deletion and three with NF1 mutation to compare their oral manifestations. Fused teeth in the mandibular anterior region were found only in the patients with deletion (2/4). Macrodontia was noted in all four patients with an NF1 deletion. Although macrodontia was also found in one patient with a mutation, it was relatively mild compared to the deletion patients. Dental caries were observed in both NF1 deletion (4/4) and mutation (2/3) patients. However, patients with NF1 deletions showed more apparently severe caries (average number of dental caries 12.8) than those with NF1 mutation (average number 5.5). Other features also noted in patients with both deletions and mutations were high-arched palate, hypodontia and malocclusion. Our study might suggest that fused teeth, macrodontia and increased dental caries are distinctive manifestations of NF1 deletion. Providing comprehensive dental care from early infancy would be very important to prevent dental caries especially in patients with NF1 deletion.

Rare dental manifestation in Simpson-Golabi-Behmel syndrome

Simpson-Golabi-Behmel syndrome (SGBS) is a rare X-linked recessive overgrowth disorder with prominent craniofacial manifestations. Macrodontia is also an uncommon dental anomaly that can be an isolated finding and has been associated with numerous systemic conditions and syndromes. This case report describes this previously unreported dental anomaly, macrodontia, in a patient with SGBS, which may broaden the phenotype of this syndrome. A brief review of the literature on orofacial findings associated with SGBS is also presented.

Macrodontic maxillary incisor in alagille syndrome

This case report describes the surgical-orthodontic guided-eruption of a deeply impacted macrodontic maxillary central incisor in a 10-year-old patient with Alagille syndrome (ALGS). In the first stage, orthodontic treatment with fixed appliance on deciduous teeth allowed to create enough space for the eruption of the maxillary right central incisor. The second stage included closed surgical exposure and vertical traction. After impacted tooth erupted in the proper position, accessory periodontal treatment and dental reshaping procedures may be indicated to camouflage macrodontic incisor with the adjacent teeth. This is the first report that presents a patient with ALGS undergoing orthodontic and surgical treatment.

Syndontia with talon cusp

Teeth are specialized structural components of the craniofacial skeleton. Developmental defects occur either alone or in combination with other birth defects. Macrodontia of anterior teeth may occur as an isolated condition or as a result of fusion or gemination and can occur in the primary or permanent dentition. Fusion is more commonly seen in the anterior maxillary region. This case presentation reports a case of fusion of a supplemental tooth to one in the normal series in conjunction with a talon cusp. This condition is extremely rare and has been reported at fourth occasion in the literature. The etiology, prevalence, clinical features, and management of the aforementioned anomalies have been reviewed in detail. Early diagnosis of this condition is important because it may cause clinical problems, such as esthetic concerns and tooth crowding.

Isolated bilateral macrodontia of mandibular second premolars: A case report

Isolated bilateral macrodontia of mandibular second premolars is an extremely rare dental anomaly with only 5 cases reported to date. This case report presents clinical and radiographic findings of isolated bilateral macrodontia in a 12-year-old child. The patient was referred to the clinic with local crowding of mandibular posterior teeth. Radiographic findings revealed the presence of impacted macrodont mandibular second premolars and their distinct morphological appearance, characterized by large, multitubercular, molariform crowns, and tapering, single roots. Following surgical removal of the impacted premolars, orthodontic therapy was initiated to correct the malocclusion. Along with the features and treatment of this rare anomaly, this case report also illustrates the benefits, in terms of treatment planning and surgical technique, of supplementing conventional radiography with cone-beam computed tomography to localize the macrodont premolars and accurately establish their relationship with the neighboring roots and anatomic structures.

Fused upper central incisors: management of two clinical cases

This paper reports the management of two clinical cases, in which the upper right central incisor was fused with a supernumerary tooth and the upper left central incisor was macrodontic. A radiographic examination revealed that the fused teeth had two separate roots. Hemisectioning of the fused teeth was performed, the supernumerary portion was extracted and the remaining part was reshaped to remove any sharp margins and to achieve a normal morphology. The macrodontic central incisors were not treated. At 12-months post-surgery there were no periodontal problems and no hypersensitivity. Orthodontic treatment was performed to appropriately align the maxillary teeth and to correct the malocclusion.