Triin Jagomägi

MTHFR and MSX1 contribute to the risk of nonsyndromic cleft lip/palate

Recent studies suggest that multiple interacting loci, with possible additional environmental factors, influence the risk for nonsyndromic oral clefts, one of the most common birth defects in humans. Advances in high-throughput genotyping technology allow the testing of multiple markers, simultaneously, in many candidate genes. We tested for associations between 176 haplotype-tagging single nucleotide polymorphisms (SNPs) in 18 candidate genes/loci and nonsyndromic clefts in a case-control study in an Estonian sample (153 patients, 205 controls). The most significant associations with nonsyndromic cleft lip with or without cleft palate (CL/P) were found for SNPs in MSX1, MTHFR, and PVRL2, including several common haplotypes in the MTHFR and MSX1 genes. The strongest association was observed for rs6446693 in the MSX1 region, which remained statistically significant after Bonferroni correction. The strongest association with nonsyndromic cleft palate (CP) was found for the SNP rs11624283 in the JAG2 gene. Epistatic interactions were observed for SNPs within PVRL2, between BCL3 and EDN1, and between IRF6 and MSX1 genes. This study provides further evidence implicating MSX1 and MTHFR in the etiology of nonsyndromic CL/P across different populations.

Replication of Novel Susceptibility Locus for Nonsyndromic Cleft Lip With or Without Cleft Palate on Chromosome 8q24 in Estonian and Lithuanian Patients

Cleft lip with or without cleft palate (CL/P) is one of the mostcommonhumanbirthdefects.CL/Pmayoccuraspartofacomplexmalformation syndrome or, as is more commonly the case, as anonsyndromic malformation. In European populations non-syndromic cleft lip with or without cleft palate (NSCL/P) has abirth prevalence of 1/700–1/1,000. NSCL/P has a multifactorialetiology resulting from interactions between multiple genetic andenvironmentalfactors.Nonsyndromiccleftpalateonly(NSCPO)isthe second most common form of nonsyndromic clefting, with aprevalence of 1/2,000 in most European populations. AlthoughNSCL/P and NSCPO are generally considered to be develop-mentally and genetically distinct entities, there is evidence thatthey may have an etiological overlap [Kondo et al., 2002; Sivertsenet al., 2008].The identification of susceptibility genes for NSCL/P has beenthe subject of extensive research. Of the many candidate genesinvestigated, however, only the IRF6 gene has shown a convincingdegreeofconsistencyacrossstudies[Zuccheroetal.,2004;Rahimovet al., 2008]. The first genome-wide association scan (GWAS)recently reported a new major susceptibility locus at chromosome8q24.21,with the strongestassociationsignal having been observedfor rs987525 (P¼3.34 10

A Missense Mutation in DUSP6 is Associated with Class III Malocclusion

Class III malocclusion is a common dentofacial phenotype with a variable prevalence according to ethnic background. The etiology of Class III malocclusion has been attributed mainly to interactions between susceptibility genes and environmental factors during the morphogenesis of the mandible and maxilla. Class III malocclusion shows familial recurrence, and family-based studies support a predominance of an autosomal-dominant mode of inheritance. We performed whole-exome sequencing on five siblings from an Estonian family affected by Class III malocclusion. We identified a rare heterozygous missense mutation, c.545C>T (p.Ser182Phe), in the DUSP6 gene, a likely causal variant. This variant co-segregated with the disease following an autosomal-dominant mode of inheritance with incomplete penetrance. Transcriptional activation of DUSP6 has been presumed to be regulated by FGF/FGFR and MAPK/ERK signaling during fundamental processes at early stages of skeletal development. Several candidate genes within a linkage region on chromosome 12q22-q23 – harboring DUSP6 – are implicated in the regulation of maxillary or mandibular growth. The current study reinforces that the 12q22-q23 region is biologically relevant to craniofacial development and may be genetically linked to the Class III malocclusion.

Variation in FGF1, FOXE1, and TIMP2genes is associated with nonsyndromic cleft lip with or without cleft palate

BACKGROUND Nonsyndromic cleft lip with or without cleft palate (CL/P) is a common complex birth defect caused by the interaction between multiple genes and environmental factors. METHODS Five hundred and eighty-seven single nucleotide polymorphisms in 40 candidate genes related to orofacial clefting were tested for association with CL/P in a clefting sample composed of 300 patients and 606 controls from Estonian, Latvian, and Lithuanian populations. RESULTS In case-control comparisons, the minor alleles of FGF1 rs34010 (p = 4.56 × 10(-4) ), WNT9B rs4968282 (p = 0.0013), and FOXE1 rs7860144 (p = 0.0021) were associated with a decreased risk of CL/P. Multiple haplotypes in FGF1, FOXE1, and TIMP2 and haplotypes in WNT9B, PVRL2, and LHX8 were associated with CL/P. The strongest association was found for protective haplotype rs250092/rs34010 GT in the FGF1 gene (p = 5.01 × 10(-4) ). The strongest epistatic interaction was observed between the COL2A1 and WNT3 genes. CONCLUSIONS Our results provide for the first time evidence implicating FGF1 in the occurrence of CL/P, and support TIMP2 and WNT9B as novel loci predisposing to CL/P. We have also replicated recently reported significant associations between variants in or near FOXE1 and CL/P. It is likely that variation in FOXE1, TIMP2, and the FGF and Wnt signaling pathway genes confers susceptibility to nonsyndromic CL/P in Northeastern European populations.

Genetic Variants in COL2A1, COL11A2, and IRF6 Contribute Risk to Nonsyndromic Cleft Palate

BACKGROUND Orofacial clefts are among the most common birth defects with a strong genetic component. Nonsyndromic cleft palate (NSCP) is a complex malformation determined by the interaction between multiple genes and environmental risk factors. METHODS We conducted a case-control association study to investigate the role of 40 candidate genes in predisposition to orofacial clefting. Five hundred ninety-one haplotype tagging single nucleotide polymorphism (tagSNPs) were genotyped in a clefting sample from the Baltic region, composed of 104 patients with nonsyndromic cleft palate and 606 controls from an Estonian, Latvian, and Lithuanian population. RESULTS In case-control comparisons, the minor alleles of IRF6 rs17389541 (p = 5.45 × 10(-4)) and COL2A1 rs1793949 (p = 7.26 × 10(-4)) were associated with increased risk of NSCP. Multiple haplotypes in COL2A1 and COL11A2 and haplotypes in WNT3, FGFR1, and CLPTM1were associated with NSCP. The strongest associations were found for IRF6 haplotype rs17389541/rs9430018 GT (p = 2.23 × 10(-4)) and COL2A1 haplotype rs12822608/rs6823 GC (p = 3.68 × 10(-4)). The strongest epistatic interactions were observed between MSX1 and BMP2, FGF1 and PVRL2, and COL2A1 and FGF2 genes. CONCLUSIONS This study provides for the first time evidence of the implication of IRF6, COL2A1, and WNT3 in the occurrence of NSCP. It is likely that variation in cartilage collagen II and XI genes, IRF6, and the Wnt and FGF signaling pathway genes contributes susceptibility to nonsyndromic cleft palate in Northeastern European populations.

Susceptibility locus for non-syndromic cleft lip with or without cleft palate on chromosome 10q25 confers risk in Estonian patients.

Non-syndromic cleft lip with or without cleft palate (NSCL/P) is one of the most common birth defects and has a multifactorial etiology that includes both genetic and environmental factors. Recently, two novel susceptibility loci and three suggestive loci for NSCL/P were identified by a genome-wide association scan (GWAS) in a German population with subsequent independent replication in a mixed European population. The aim of the present study was to investigate whether these newly detected loci confer similar effects in the North-East European Baltic population. A total of 101 NSCL/P patients and 254 controls from Estonia were included. A significant association was observed for rs7078160 (P = 0.0016) at chromosome 10q25, which confirms the association of this locus with NSCL/P in the Baltic population. No significant association was found for the other four loci, a result that may have been attributable to the limited power of the sample.

Non-syndromic Tooth Agenesis Associated with a Nonsense Mutation in Ectodysplasin-A (EDA)

Mutations in the ectodysplasin-A (EDA) gene have been generally associated with X-linked hypohidrotic ectodermal dysplasia (XLHED). Recently, missense mutations in EDA have been reported to cause familial non-syndromic tooth agenesis. In this study, we report a novel EDA mutation in an Estonian family segregating non-syndromic tooth agenesis with variable expressivity. Affected individuals had no associated defects in other ectodermal organs. Using whole-exome sequencing, we identified a heterozygous nonsense mutation c.874G>T (p.Glu292X) in the TNF homology domain of EDA in all affected female patients. This protein-altering variant arose de novo, and the potentially causative allele was transmitted to affected offspring from the affected mother. We suggest that the dental phenotype variability described in heterozygous female carriers of EDA mutation may occur because of the differential pattern of X-chromosome inactivation, which retains reduced levels of EDA-receptor signaling in tissues involved in tooth morphogenesis. This results in selective tooth agenesis rather than XLHED phenotype. The present study broadens the mutation spectrum for this locus and demonstrates that EDA mutations may result in non-syndromic tooth agenesis in heterozygous females.

Contemporary management of TMJ involvement in JIA patients and its orofacial consequences.

Juvenile idiopathic arthritis is the most common chronic rheumatic condition during childhood. Temporomandibular joint arthritis is frequently asymptomatic. When it takes place during childhood, it may affect condylar growth; therefore, these children are at risk of unfavorable long-term outcomes from the associated joint damage. The etiology is not completely understood, but it is considered as multifactorial with both genetic and environmental factors involved.The standardized examination and imaging protocols serve important purpose to diagnose temporomandibular joint (TMJ) arthritis not only to establish an early interventional strategy but also to assess craniofacial growth and the progression of signs and symptoms in those patients. Although the treatment of juvenile idiopathic arthritis (JIA) has changed dramatically over the last decades due to new therapeutic options, TMJ arthritis still can develop during the course of the disease. In clinical experience, TMJs appear to respond less well to the standard of care used to treat other joints. More individualized approach to the patient’s treatment serves as the main goal of personalized medicine. It could be achieved by adopting new methods of medical imaging such as conebeam computer tomography as well as developing reliable biomarkers which may assist with predicting disease type, course, or severity and predicting response to medication.This article provides an overview of current information on orofacial complications in JIA and its management. Based on information provided in this review, more precise diagnosis, proper tools for recognizing people at risk, and more efficient treatment approaches could be implemented. This may lead to more personalized treatment management strategies of TMJ complications of JIA patients.

The Need for Orthodontic Treatment among Vietnamese School Children and Young Adults

Objective. The aim of this study was to evaluate the need for orthodontic treatment among 12-year-old school children and 18-year-olds from Da Nang, Vietnam. Basic Research Design. A random representative sample of 200 12-year-old children from primary schools in Da Nang city was gathered. In addition, 200 18-year-old students were randomly selected from among the 4000 students studying at Da Nang University of Medical Technology and Pharmacy, Vietnam. All the subjects were evaluated according to Angles molar relationship, the presence of malocclusion, and the components of the Index of Orthodontic Treatment Need (Dental Health Component, DHC, and Aesthetic Component, AC). Results. The DHC of index of orthodontic treatment need (IOTN) for 12-year-olds was in 60% of cases no or little, in 21% of cases moderate, and in 19% of cases definitive, while the prevalence of moderate and definitive need for treatment among the 18-year-olds was 24% and 30.5%, respectively. The prevalence of class III malocclusion, contact point displacement, and crossbite was higher in 18-year-olds than among the 12-year-olds, while the prevalence of increased overjet and increased overbite had decreased in 18-year-olds compared to the group of 12-year-olds. Conclusions. There is a strong need for orthodontic treatment in Vietnams population. The need for orthodontic treatment was determined by contact point displacement, crossbite, increased overjet, and increased overbite.

Normative nasalance scores for Vietnamese-speaking children

Abstract Objective: The Nasometer is increasingly being used to complement auditory perceptual assessment of nasality. Nasalance scores which are obtained from the Nasometer vary across languages. Normative nasalance scores have been established for many languages but not for the Vietnamese language. The objective of this study was to obtain the normative nasalance scores for Vietnamese-speaking children. Participants: In this study, 102 healthy Vietnamese children speaking in the central regional dialect aged from 7 to 9 years (45 boys, 57 girls; mean age = 7.5 years) at a primary school in Hue, Vietnam participated. Procedures: Three speech stimuli, which were specific for the Vietnamese language, were designed: oral stimuli (19 words and 18 sentences), oro-nasal stimuli (eight sentences) and nasal stimuli (seven sentences). The children were asked to repeat these stimuli after the examiner. The Nasometer II (model 6450) was used to obtain the nasalance scores. The procedure took about 10 minutes for each child. Results: The mean nasalance scores and the standard deviation of each stimulus were: 13.1 ± 5.8 (oral stimuli), 30.7 ± 6.6 (oro-nasal stimuli) and 56.9 ± 9.2 (nasal stimuli). No significant differences between the genders were found. Conclusions: The normative nasalance scores provide essential reference information for clinicians who deal with nasalance disorders, especially patients with cleft palate. The nasalance scores in this study were established for Vietnamese children speaking in the central regional dialect and can be applied to both genders.