WNT10B mutations associated with isolated dental anomalies.

Isolated hypodontia is the most common human malformation. It is caused by heterozygous variants in various genes, with heterozygous WNT10A variants being the most common cause. WNT10A and WNT10B are paralogs that likely evolved from a common ancestral gene after its duplication. Recently, an association of WNT10B variants with oligodontia (severe tooth agenesis) has been reported. We performed mutational analysis in our cohort of 256 unrelated Thai families with various kinds of isolated dental anomalies. In 7 families afflicted with dental anomalies we detected 4 heterozygous missense variants in WNT10B. We performed whole exome sequencing in the patients who had WNT10B mutations and found no mutations in other known hypodontia-associated genes, including WNT10A, MSX1, PAX9, EDA, AXIN2, EDAR, EDARADD, LPR6, TFAP2B, LPR6, NEMO, KRT17, and GREM2. Our findings indicate that the variants c.475G>C [p.(Ala159Pro)], found in 4 families, and c.1052G>A [p.(Arg351His)], found in 1 family, are most probably causative. They also show that WNT10B variants are associated not only with oligodontia and isolated tooth agenesis, but also with microdontia, short tooth roots, dental pulp stones, and taurodontism.

Dentin Dysplasia in Notum Knockout Mice.

Secreted WNT proteins control cell differentiation and proliferation in many tissues, and NOTUM is a secreted enzyme that modulates WNT morphogens by removing a palmitoleoylate moiety that is essential for their activity. To better understand the role this enzyme in development, the authors produced NOTUM-deficient mice by targeted insertional disruption of the Notum gene. The authors discovered a critical role for NOTUM in dentin morphogenesis suggesting that increased WNT activity can disrupt odontoblast differentiation and orientation in both incisor and molar teeth. Although molars in Notum(-/-) mice had normal-shaped crowns and normal mantle dentin, the defective crown dentin resulted in enamel prone to fracture during mastication and made teeth more susceptible to endodontal inflammation and necrosis. The dentin dysplasia and short roots contributed to tooth hypermobility and to the spread of periodontal inflammation, which often progressed to periapical abscess formation. The additional incidental finding of renal agenesis in some Notum (-/-) mice indicated that NOTUM also has a role in kidney development, with undiagnosed bilateral renal agenesis most likely responsible for the observed decreased perinatal viability of Notum(-/-) mice. The findings support a significant role for NOTUM in modulating WNT signaling pathways that have pleiotropic effects on tooth and kidney development.

GREMLIN 2 Mutations and Dental Anomalies.

Isolated or nonsyndromic tooth agenesis or hypodontia is the most common human malformation. It has been associated with mutations in MSX1, PAX9, EDA, AXIN2, EDAR, EDARADD, and WNT10A. GREMLIN 2 (GREM2) is a strong bone morphogenetic protein (BMP) antagonist that is known to regulate BMPs in embryogenesis and tissue development. Bmp4 has been shown to have a role in tooth development. Grem2(-/-) mice have small, malformed maxillary and mandibular incisors, indicating that Grem2 has important roles in normal tooth development. Here, we demonstrate for the first time that GREM2 mutations are associated with human malformations, which include isolated tooth agenesis, microdontia, short tooth roots, taurodontism, sparse and slow-growing hair, and dry and itchy skin. We sequenced WNT10A, WNT10B, MSX1, EDA, EDAR, EDARADD, AXIN2, and PAX9 in all 7 patients to rule out the effects of other ectodermal dysplasias and other tooth-related genes and did not find mutations in any of them. GREM2 mutations exhibit variable expressivity even within the same families. The inheritance is autosomal dominant with incomplete penetrance. The expression of Grem2 during the early development of mouse teeth and hair follicles and the evaluation of the likely effects of the mutations on the protein structure substantiate these new findings.

Cleft lip with cleft palate, ankyloglossia, and hypodontia are associated with TBX22 mutations.

X-linked cleft palate and ankyloglossia (CPX) are caused by mutations in the TBX22 transcription factor. To investigate whether patients with ankyloglossia alone or in the presence of other craniofacial features including hypodontia or CLP might be caused by TBX22 mutations, we analyzed 45 Thai patients with isolated ankyloglossia, 2 unusual CPA families, and 282 non-syndromic Thai and UK patients with CLP. Five putative missense mutations were identified, including 3 located in the T-box binding domain (R120Q, R126W, and R151L) that affects DNA binding and/or transcriptional repression. The 2 novel C-terminal mutations, P389Q and S400Y, did not affect TBX22 activity. Mutations R120Q and P389Q were identified in patients with ankyloglossia only, while R126W and R151L were present in families that included CLP. Several individuals in these families were also found to have micro/hypodontia. This study has expanded the phenotypic spectrum of TBX22-related mutations to include dental anomalies and cleft lip.

Children's attitudes toward behavior management techniques used by dentists.

PURPOSE: Many behavior management techniques (BMTs) are used in dental offices. The objective of this study was to evaluate how children felt towards the BMT used in the dental office by using the newly invented "attitude meter." METHODS: Two hundred forty children 6 to 17 years old were selected randomly to participate in the study. Each student was asked to watch 8 video scenes of live BMTs. The BMTs used consisted of: (1) tell-show-do (TSD); (2) rewards; (3) general anesthesia; (4) papoose board; (5) hand-holding; (6) mouthprop; (7) voice control; and (8) hand-over-mouth exercise (HOME). After watching each BMT scene, the children were instructed to express their attitude towards the BMT by drawing a "line of favor"--the newly invented attitude meter. RESULTS: It was found that TSD and HOME were the most and least favorite BTM, respectively. Those who had dental experience appeared to have worse attitudes. Older and younger children had different opinions towards some BMTs. The older children preferred the papoose board and hand-holding to the mouthprop. All children preferred the use of the papoose board and hand-holding to voice control. CONCLUSIONS: Children appeared to judge a behavior management technique according to the way it looked. The "line of favor" is a reliable tool to measure attitudes of children over 6 years old.

Heterozygous mutation in the SAM domain of p63 underlies Rapp-Hodgkin ectodermal dysplasia.

Several ectodermal dysplasia syndromes, including Ectrodactyly-Ectodermal dysplasia-Clefting (EEC) and Ankyloblepharon-Ectodermal Dysplasia-Clefting (AEC) syndromes, are known to result from mutations in the p63 gene. We investigated whether Rapp-Hodgkin syndrome (RHS) is also caused by mutations in the p63 gene. We identified a heterozygous de novo germline missense mutation, S545P, in the sterile-alpha-motif (SAM) domain of p63, in a Thai patient affected with RHS. This is the first genetic abnormality to be described in RHS. The amino acid substitution is the most downstream missense mutation in p63 reported thus far. Histological assessment of a skin biopsy from the patient's palm showed hyperkeratosis and keratinocyte cell-cell detachment in the upper layers of the epidermis, along with numerous apoptotic keratinocytes. Collectively, these investigations demonstrate that RHS is also caused by mutations in p63 and that the clinical similarities to AEC syndrome are paralleled by the nature of the inherent mutation.

Mental retardation, obesity, mandibular prognathism with eye and skin anomalies (MOMES syndrome): a newly recognized autosomal recessive syndrome.

We report two daughters of a Thai family affected with mental retardation, delayed speech, obesity, craniofacial manifestations, and ocular anomalies. Craniofacial manifestations included macrocephaly, maxillary hypoplasia, mandibular prognathism, and crowding of teeth. Ocular anomalies consisted of blepharophimosis, blepharoptosis, decreased visual acuity, abducens palsy, hyperopic astigmatism, and accommodative esotropia. Chronic atopic dermatitis, lateral deviation of the great toes, and cone-shaped epiphyses of the toes were observed. The disorder is suggested to be autosomal recessive. The combination of findings found in our patients has not hitherto been described.

A newly recognized syndrome of skeletal dysplasia with opalescent and rootless teeth.

A Thai girl with skeletal dysplasia and dental anomalies was seen. Her anomalies consisted of disproportionately short stature, short neck, broad and depressed nasal bridge, broad chest in the anteroposterior dimension, kyphosis, widely spaced nipples, and protruded abdomen. Radiographic testing indicated that she had a large sella turcica, platyspondyly, hypoplastic acetabulum, and a small body of mandible. Both her deciduous and permanent teeth were equally opalescent, and most were rootless, with root development of the mandibular teeth more severely affected. Some maxillary roots were extremely short and tapered. Hypodontia was also observed. These findings represent a unique and hitherto undescribed syndrome of skeletal dysplasia with concomitant dental anomalies.

Digitotalar dysmorphism with craniofacial and other new associated abnormalities.

We report digitotalar dysmorphism in a grandfather, father, and a daughter. All the affected members had clasped thumbs. The father had a short stature, large zygomatic arch and a flat mandibular condyle. The newly recognized findings found in the affected girl were large maxillary deciduous central incisors, a short proximal phalanx of the second finger, and a large subcutaneous hemangioma of the back. Her paternal grandfather had only congenital clasped thumbs. Congenital clasped thumb is a very heterogeneous anomaly and related to many syndromes. The findings in the reported family which are consistent with digitotalar dysmorphism, include congenital clasped thumbs, ulnar deviation of fingers, and a congenital vertical tali.

Laurin-Sandrow syndrome with additional associated manifestations.

A Thai man with Laurin-Sandrow syndrome (LSS, MIM 135750), the ninth reported case, is described. He had an underdeveloped nasal bone, scar-like seams under the nose, large heads of mandibular condyles, and brachymesophalangy of toes as newly observed findings of the syndrome. He also had mental retardation. The patient had duplication of ulna, with triphalangeal thumbs, and polydactyly of one finger. The triphalangeal thumbs were non-opposable. Carpal bones were malformed. Mirror image polydactyly of the toes was present. There were nine toes on the right and eight on the left. Joint abnormalities were observed at his elbows, wrists, knees, ankles, fingers, and toes. Synostosis of severely malformed tarsal bones was noted. This appears to be the first case of LSS with anomalies not limited to the nose and limbs. The relationship between LSS, tibial hemimelia-polysyndactyly-triphalangeal thumbs syndrome, triphalangeal thumb-polysyndactyly syndrome, preaxial polydactyly types 2 and 3, and Haas-type syndactyly is discussed.

Are triphalangeal thumb-polysyndactyly syndrome (TPTPS) and tibial hemimelia-polysyndactyly-triphalangeal thumb syndrome (THPTTS) identical? A father with TPTPS and his daughter with THPTTS in a Thai family.

We report on a Thai man who had triphalangeal thumb-polysyndactyly syndrome (TPTPS, MIM *190605) and his daughter who had tibial hemimelia-polysyndactyly-triphalangeal thumb syndrome (THPTTS, MIM *188770). The father had polysyndactyly of triphalangeal thumbs, syndactyly of fingers, duplicated distal phalanx of the left great toe, brachymesophalangy of toes, and the absence of middle phalanges of some toes. He was diagnosed as having TPTPS. His daughter was more severely affected, having complete syndactyly of five-fingered hands in rosebud fashion (Haas-type syndactyly), hypoplastic tibiae, absent patellae, thick and displaced fibulae, preaxial polysyndactyly of triphalangeal toes, and cutaneous syndactyly of some toes, the manifestations being consistent with THPTTS. Having two different syndromes in the same family suggests that they are actually the same disorder. A literature survey showed that there have been several families where THPTTS occurred with TPTPS or Haas-type syndactyly (and/or preaxial polydactyly type 2, PPD2). In addition, all loci for TPTPS, THPTTS, and PPD2 (and/or PPD3) have been assigned to chromosome band 7q36. These findings support our conclusion that TPTPS, PPD2 (and/or PPD3), and Haas-type syndactyly are a single genetic en-tity (THPTTS). We propose to call the condition "tibial hemimelia-polysyndactyly-triphalangeal thumbs syndrome."

Juberg-Hayward syndrome: a new case report and clinical delineation of the syndrome.

We report a new case of Juberg-Hayward (orocraniodigital) syndrome (JHS). This 7-year-old Thai boy had characteristic features together with a number of newly recognized findings. Those findings are humeroradial synostosis (HRS), carpal anomalies, simian crease, brachydactyly A4, widely spaced nipples, seizures and myopia. Clinical delineation and correlation between the phenotypes of the syndrome are discussed.

Robinow (fetal face) syndrome: report of a boy with dominant type and an infant with recessive type.

The cases of two patients with Robinow fetal face syndrome, an 11-year-old Thai boy and a newborn Caucasian girl, are described. The Thai boy had the characteristics typical of the dominant type of the syndrome with a few newly recognized signs, including communicating hydrocephalus, underdeveloped sinuses, short roots of the teeth, narrow and thick-floored pulp chambers, hypoplastic nipples, absent middle phalanges of the second to fifth toes, cone-shaped epiphyses of the second and fourth fingers and fifth toes, single creases of the fourth and fifth fingers, clinodactyly of the third fingers, dysmorphic umbilicus, and shawl scrotum. The girl had anomalies typical of the recessive type of the syndrome. She also had capillary hemangioma at the tip of her nose and hypoplastic fourth metatarsal bones, which are the newly recognized features of the recessive type. Infrequently reported clinical manifestations of the syndrome are discussed.

Rapp-Hodgkin syndrome with palmoplantar keratoderma, glossy tongue, congenital absence of lingual frenum and of sublingual caruncles: newly recognized findings.

We report on a boy with Rapp-Hodgkin syndrome (RHS) or Rapp-Hodgkin ectodermal dysplasia. He had sparse, wiry, slow growing and uncombable hair, but no pili torti or pili canaliculi characteristic of RHS. He also had sparse eyelashes and eyebrows, and obstructed lacrimal puncta and epiphora. Bilateral bony external auditory canal stenosis led to hearing loss. The mouth was small with repaired bilateral cleft lip and palate. Oral manifestations included hypodontia, microdontia, unerupted mandibular premolars with well formed roots, large dental pulp spaces, enamel hypoplasia, multiple caries, glossy tongue, and congenital absence of lingual frenum and of sublingual caruncles including submandibular and sublingual salivary duct openings. Palmo-plantar keratoderma, unerupted premolars, congenital absence of lingual frenum, sublingual caruncles, glossy tongue, and pili canaliculi seen in the patient are newly recognized findings of this syndrome. Overlapping findings of RHS ectrodactyly-ectodermal dysplasia-clefting syndrome (EEC), and ankyloblepharon-ectodermal defects-cleft lip and palate syndrome (AEC) are discussed.

The gene for mesomelic dysplasia Kantaputra type is mapped to chromosome 2q24-q32.

Mesomelic dysplasia Kantaputra type (MDK) (MIM *156232) is a new autosomal dominant skeletal dysplasia characterized by dwarfism, shortening of the forearms/lower-legs, carpal/tarsal synostosis, and dorsolateral foot deviation. We studied a Thai family in which 15 members in 3 generations were affected with MDK. With reference to the breakpoints of a balanced translocation [t(2;8)(q31;p21)] in patients from a previously reported Italian family with a skeletal dysplasia that appears similar to MDK, a linkage analysis was performed in the Thai family using 50 CA-repeat markers mapped to nearby regions (2q22-q34 and 8p24-p21) of the translocation breakpoints. The results clearly ruled out a linkage of MDK to marker loci at the 8p24-p21 region, whereas all nine affected members available for the study shared a haplotype at four loci (D2S2284, D2S326, D2S2188, and D2S2314) spanning about 22.7 cM in the 2q24-q32 region. The computer-assisted two-point linkage analysis revealed maximum logarithm of odds (lod) scores of 4.82, 4.21, 4.82, and 4.21 (theta = 0) at these loci, respectively. These data indicated that the MDK locus is in the vicinity of D2S2284 and D2S2188 loci that are most likely mapped to 2q24-q32.

Dominant mesomelic dysplasia, ankle, carpal, and tarsal synostosis type: a new autosomal dominant bone disorder.

A new type of mesomelic dysplasia was in 3 generations of a large Thai family. It is characterized by bilateral symmetrical marked shortening of the ulnae and shortening and bowing of the radii. The proximal fibula is usually short and synostoses are present between the tibia and fibula and the small malformed calcaneus and talus. The prominent calcanei on the ventral surfaces of the distal fibulae are a characteristic feature of the new type. Carpal and tarsal synostoses are present in some affected people. All affected individuals walk on the tips of their toes with the dorsal foot deviated laterally. The deformities of the radius and ulna somewhat resemble those of mesomelic dysplasia, Langer type, but otherwise the condition is distinctly different. This new mesomelic dysplasia is an autosomal dominant trait with complete penetrance and variable expressivity over 3 generations.

Double dens invaginatus of molarized maxillary central incisors, premolarization of maxillary lateral incisors, multituberculism of the mandibular incisors, canines and first premolar, and sensorineural hearing loss.

Molarization and premolarization of anterior teeth have never been reported before. Double dens invaginatus is an extremely rare condition. We describe an affected female who had developmental delay and congenital progressive sensorineural hearing loss. Double dens invaginatus of molarized maxillary central incisors and premolarized maxillary lateral incisors were present. In addition, multituberculated mandibular incisors, canines, and first premolar were observed. Histologically, tooth structure was unremarkable. Family history of dental abnormalities and hearing loss was denied. Clinical and radiographic examinations were those performed when the patient was 7 and 13 years old. The basic defect is postulated to be of mesenchymal origin.