EDAR Research Articles

Uneven Influx of European-Specific Alleles of SLC45A2, SLC24A5, TYRP1, DRD2, EDAR, and OCA2 Genes into the Gene Pool of the Koryaks

The distribution of alleles highly specific to Europeans in the Koryak gene pool, which formed as a result of intensive interethnic admixture in the Northern Priokhotie, characterized by the prevailing genetic contribution from males of Eastern European origin, was analyzed. The loci rs16891982 (SLC45A2 gene), rs1426654 (SLC24A5 gene), rs1408799 (TYRP1 gene), rs1076563 (DRD2 gene), rs3827760 (EDAR gene), and rs1448485 (OCA2 gene), which are mainly associated with the pigmentation system, were selected for analysis. High heterogeneity was found in the frequency of European-specific alleles, ranging from 1.4% for the variant rs1076563-C of the DRD2 gene to 14.7% for the variant rs1426654-A of the SLC24A5 gene. The reasons for the uneven influx of European-specific alleles into the Koryak gene pool are discussed. It is possible that the formation of genetic structure of modern Koryaks under intensive interethnic admixture was accompanied by the influence of natural selection on some parts of the genome.

Novel homozygous frameshift insertion variant in the last exon of the EDARADD causing hypohidrotic ectodermal dysplasia in two siblings: case report and review of the literature

BackgroundHypohidrotic ectodermal dysplasia (HED) is a genetic disorder that results in the abnormal development of structures derived from ectodermal tissue. This rare condition predominantly affects the hair, nails, eccrine glands, and teeth. While HED can be caused by various genes, the EDA, EDAR, EDARADD, and WNT10A genes account for approximately 90% of cases. Notably, HED forms associated with variants in the EDA, EDAR, or EDARADD genes may exhibit similar phenotypes due to defects in a common signaling pathway. Proper interaction among the products of these genes is crucial for the activation of the nuclear factor (NF-κB) signaling pathway, which subsequently regulates the transcription of targeted genes. The EDARADD gene, in particular, harbors one of the rarest reported variants associated with HED.Case presentationFive-and two-years-old brothers born into consanguineous parents were examined at our outpatient medical genetics clinic at Sanliurfa Training and Research Hospital, Turkey. Both displayed the same classical phenotypic features of HED. The elder had a very sparse dark and brittle hair, sparse eyebrows and eyelashes, conical upper and lower premolar teeth with hypodontia, widely spaced teeth, very dry skin, mildly prominent forehead, and periorbital wrinkles. The younger one showed the same, but less severe, clinical features. After thorough examination and patient history evaluation, targeted next-generation sequencing analysis yielded the novel homozygous insertion variant c.322_323insCGGGC p.(Arg108ProfsTer7) in EDARADD. The mutation has not been reported to date in the literature.ConclusionsIn this report, we present two siblings exhibiting classical HED symptoms and a novel insertion variant of the EDARADD gene, which leads to a frameshift introducing a stop codon. Both brothers inherited such mutation from their parents, who were heterozygous carriers of the same variant. The present study may shed light about the pathogenic mechanisms underlying HED, and expand the spectrum of EDARADD gene variants associated with this condition.

Fine Wrinkle Improvement through Bioactive Materials That Modulate EDAR and BNC2 Gene Expression.

Skin aging is a multifaceted biological phenomenon influenced by a combination of intrinsic or extrinsic factors. There is an increasing interest in anti-aging materials including components that improve skin wrinkles. Despite the availability of several such wrinkle-improving materials, the demand for ingredients with outstanding efficacy is increasing. Therefore, this study aimed to explore the mechanisms of wrinkle-related genes reported in previous genome-wide association studies (GWASs), identify materials that regulate these genes, and develop an effective anti-wrinkle formula containing the active ingredients that regulate the expression of these genes. We selected two candidate genes, EDAR and BNC2, that are reportedly related to periorbital wrinkles. We investigated their functions in the skin through in vitro experiments using human skin cell lines (keratinocytes and fibroblasts). Moreover, we identified ingredients that regulate the expression of these two genes and confirmed their efficacy through in vitro experiments using the skin cell lines. Finally, we developed a formula containing these ingredients and confirmed that it enhanced dermal collagen in the 3D skin and improved fine wrinkles under the eyes more effectively than retinol in humans, when applied for 8 weeks. Our results are significant and relevant, as we have discovered a special formula for wrinkle improvement with reliable efficacy that surpasses the efficacy of retinol and does not cause side-effects such as skin irritation.

Activation of wnt/β-catenin signaling pathway down regulated osteogenic differentiation of bone marrow-derived stem cells in an anhidrotic ectodermal dysplasia patient with EDA/EDAR/EDARADD mutation

ObjectiveTo explore the mechanism by which the Wnt/β-catenin pathway induces osteogenic differentiation of bone marrow-derived stem cells (BMSCs) in anhidrotic ectodermal dysplasia (AED) with an Ectodysplasin A (EDA)/EDA receptor (EDAR)/EDARADD mutation. MethodsAn AED patient served as the AED group, whereas the other patients without AED were included in the normal group. Peripheral venous blood collected from the AED patient was subjected to whole-genome resequencing. BMSCs from the mandible of patients with AED and normal individuals were isolated and cultured in vitro. Cell proliferation assay was performed to compare the growth speed of BMSCs between the AED and normal groups. CHIR-99021, an activator of the Wnt/β-catenin pathway and XAV-939, an inhibitor, was used to manage BMSCs in an osteogenic environment in both groups. The expression of β-catenin was detected by quantitative polymerase chain reaction, while that of RUNX2 was detected by western blotting. Alizarin red was used for staining. ResultsA novel mutation (c.152T > A in EDA) and two known mutations (c.1109T > C in EDAR and c.27G > A in EDARADD) were identified. The growth rate in the normal group was higher than that in the AED group. In the normal group, the number and size of calcified nodes and the expression of RUNX-2 increased with CHIR-99021 treatment, which could be inhibited by XAV-939. In contrast, CHIR-99021 inhibited osteogenesis in the AED group and this effect was promoted by XAV-939. ConclusionActivation of the Wnt/β-catenin pathway downregulates osteogenesis of BMSCs in AED patients with EDA/EDAR/EDARADD gene mutations. Further investigation in more AED patients is required, given the wide range of mutations involved in AED.

ABO gene may be salient to the out of Africa migrations to the Americas

The source populations of Native Americans lived in Asia and Eurasia some 35,000 to 40,000 years ago. Consensus is that they migrated to Beringia some 25,000 to 30,000 years ago, when the low sea levels from the Last Glacial Maximum period allowed a land bridge to form to Beringia. Subsequently, the Native American ancestors migrated south to North and South America, whereas the remaining Beringia population, Eskimos, migrated into Canada and Greenland. Genetic evidence along with anthropological research adds much to the understanding of the course of their migrations and population growth. Because present-day Native Americans are essentially all of ABO O blood type, and the other Beringia populations, the Eskimos, were polymorphic for the ABO blood groups given the extensive research revealing pleiotropy of ABO blood group alleles, this unusual population frequency distribution of ABO blood groups offers an opportunity to understand how a population with no diversity of ABO blood groups differs from one that is similar in other genes but polymorphic in ABO blood groups. ABO blood groups in migrating populations provide supporting evidence for the timelines, destinations, and cultures of those populations leaving Africa. Other genes add to the power of ABO blood groups to provide this evidence. One of those genes, in the case of Native American and Eskimo migrations, is the gene for a dental trait called shovel shaped incisors, ectodysplasin A receptor (EDAR), which is prevalent in northeast Asian populations and is fixed in Native American populations. Because of the known climatic conditions in Africa at the time of the major out-of-Africa migration periods and malaria-related climatic aspects of the selection of the ABO A2 vs ABO A1 gene, it appears that the population ratio of ABO A2 to ABO A1 and EDAR associated shovel shaped incisor frequencies is associated with the timelines of the population leaving Africa as well as their further migrations. Because Native Americans have a very high shovel shaped incisor frequency and no ABO A2, their timeline of migrating from northeast Asia and Eurasia, observed using this approach and agreeing with other lines of evidence, is supported to be 25,000–30,000 years ago. Furthermore, separation of the Beringia population into a monomorphic ABO O group, the Native Americans, and an ABO polymorphic group, the Eskimos, in light of research supporting pleiotropy of ABO alleles enhances our understanding of their respective divergent migration paths, cultures, and population growth.

Depletion of G9A attenuates imiquimod-induced psoriatic dermatitis via targeting EDAR-NF-κB signaling in keratinocyte

Psoriasis is a common and recurrent inflammatory skin disease characterized by inflammatory cells infiltration of the dermis and excessive proliferation, reduced apoptosis, and abnormal keratosis of the epidermis. In this study, we found that G9A, an important methyltransferase that mainly mediates the mono-methylation (me1) and di-methylation (me2) of histone 3 lysine 9 (H3K9), is highly expressed in lesions of patients with psoriasis and imiquimod (IMQ)-induced psoriasis-like mouse model. Previous studies have shown that G9A is involved in the pathogenesis of various tumors by regulating apoptosis, proliferation, differentiation, and invasion. However, the role of G9A in skin inflammatory diseases such as psoriasis remains unclear. Our data so far suggest that topical administration of G9A inhibitor BIX01294 as well as keratinocyte-specific deletion of G9A greatly alleviated IMQ-induced psoriatic alterations in mice for the first time. Mechanistically, the loss function of G9A causes the downregulation of Ectodysplasin A receptor (EDAR), consequently inhibiting the activation of NF-κB pathway, resulting in impaired proliferation and increased apoptosis of keratinocytes, therefore ameliorating the psoriatic dermatitis induced by IMQ. In total, we show that inhibition of G9A improves psoriatic-like dermatitis mainly by regulating cell proliferation and apoptosis rather than inflammatory processes, and that this molecule may be considered as a potential therapeutic target for keratinocyte hyperproliferative diseases such as psoriasis.

Spatial and Temporal Expression of Ectodysplasin-A Signaling Pathway Members During Mandibular Condylar Development in Postnatal Mice.

A growing body of evidence emerging supported that ectodysplasin-A (EDA) signaling pathway contributed to craniofacial development. However, their expression in condyle has not been elucidated yet. This study investigated the expression patterns of EDA, EDA receptor (EDAR), and EDAR-associated death domain (EDARADD) in condyle of postnatal mice. Histological staining and micro-computed tomography (CT) scanning showed that as endochondral ossification proceeded, the thickness of chondrocyte layer decreased, and the volume of mandibular condyle increased. Osteoclasts remained active throughout the condylar development. Immunohistochemistry staining demonstrated that EDA was expressed in almost all layers during the first 2 weeks after birth. EDA shifted from the mature and hypertrophic layers to fibrous and proliferating layers at postnatal 3 weeks. As condyle matured, the distribution of EDA tended to be limited to hypertrophic layer. The distribution patterns of EDAR and EDARADD were consistent with EDA, while the level of EDAR expression was slightly lower. mRNA expression levels of EDA signaling pathway-related components increased after birth. Furthermore, we evaluated the expression of EDA using ATDC5 in vitro. EDA increased during the late stage of chondrogenesis. These findings proved that EDA signaling pathway was involved in condylar development and acted as a regulatory factor in condylar maturation and differentiation.

A novel ectodysplasin-A receptor gene variant identified by whole-exome sequencing with hypohidrotic ectodermal dysplasia in a Chinese family

A novel ectodysplasin-A receptor gene variant identified by whole-exome sequencing with hypohidrotic ectodermal dysplasia in a Chinese family

Measurement and analysis of the crown conical degree of maxillary incisors in patients with congenital tooth agenesis caused by different gene mutations

Objective: To measure the crown conical degree of the remaining maxillary incisors in patients with congenital tooth agenesis, and to analyze the influence of different gene mutations on the crown conical degree of patients. Methods: Whole exome sequencing was performed on 85 patients with congenital tooth agenesis (50 males, 35 females, median age 19 years old) who visited the Department of Prosthodontics, Peking University School and Hospital of Stomatology from January 2019 to January 2023. The pathogenic gene was identified. The width of the crowns of the maxillary central and lateral incisors at the incisal 1/3 and gingival 1/3 were measured on the panoramic radiograph, and the ratio was defined as the crown conical degree. The smaller the ratio is, the more likely is the crown to be peg shaped teeth. The control group was matched by age and gender with 85 other patients with intact maxillary permanent incisors who were treated in the Department of Prosthodontics, Peking University School and Hospital of Stomatology from January 2019 to January 2023. The conical degree of the tooth agenesis group was compared with the control group by t-test, and the differences in the crown conical degree in different gene mutation groups were compared using one-way analysis of variance, and the multiple comparisons among gene groups were carried out using the LSD method. Results: Among the 85 tooth agenesis patients, the numbers of patients in each gene mutation group were 20 in ectodysplasin A (EDA) group, 8 in ectodysplasin A receptor (EDAR) group, 15 in wingless-type MMTV integration site family, member 10A (WNT10A) group, 16 in paired box 9 (PAX9) group, 10 in Msh homeobox 1 (MSX1) group, 10 in low-density Lipoprotein receptor related protein 6 (LRP6) group, and 6 in bone morphogenetic protein4 (BMP4) group. The number of missing teeth were 1-27, median number 15 among the tooth agenesis patients. There was no significant difference in the conical degree between the left and right homonymous teeth in the congenital tooth agenesis group and the control group (P>0.05). The crown conical degree of maxillary central incisor and lateral incisor in the congenital missing teeth group (0.95±0.24, 0.90±0.22) was significantly smaller than that in the control group (1.12±0.09, 1.13±0.09) (t=-8.50, P<0.001; t=-11.47, P<0.001). In WNT10A mutants, the conical degree of lateral incisors (0.89±0.18) was less than that of central incisors (1.07±0.15)(t=3.68, P<0.001). The conical degree of central incisors and lateral incisors (0.70±0.23, 0.57±0.15) of EDA mutants was significantly lower than that in patients with other gene mutations (P>0.05). Conclusions: Compared with the normal control group, the remaining maxillary central and lateral incisors of the seven gene mutation groups of patients with congenital tooth agenesis all had different degrees of conical crown. Among them, the crown conical degree of maxillary central and lateral incisors of the EDA mutation was the most severe, and the WNT10A mutation affected the maxillary lateral incisors more specifically.

The role of Beringia in human adaptation to Arctic conditions based on results of genomic studies of modern and ancient populations.

The results of studies in Quaternary geology, archeology, paleoanthropology and human genetics demonstrate that the ancestors of Native Americans arrived in mid-latitude North America mainly along the Pacific Northwest Coast, but had previously inhabited the Arctic and during the last glacial maximum were in a refugium in Beringia, a land bridge connecting Eurasia and North America. The gene pool of Native Americans is represented by unique haplogroups of mitochondrial DNA and the Y chromosome, the evolutionary age of which ranges from 13 to 22 thousand years. The results of a paleogenomic analysis also show that during the last glacial maximum Beringia was populated by human groups that had arisen as a result of interaction between the most ancient Upper Paleolithic populations of Northern Eurasia and newcomer groups from East Asia. Approximately 20 thousand years ago the Beringian populations began to form, and the duration of their existence in relative isolation is estimated at about 5 thousand years. Thus, the adaptation of the Beringians to the Arctic conditions could have taken several millennia. The adaptation of Amerindian ancestors to high latitudes and cold climates is supported by genomic data showing that adaptive genetic variants in Native Americans are associated with various metabolic pathways: melanin production processes in the skin, hair and eyes, the functioning of the cardiovascular system, energy metabolism and immune response characteristics. Meanwhile, the analysis of the existing hypotheses about the selection of some genetic variants in the Beringian ancestors of the Amerindians in connection with adaptation to the Arctic conditions (for example, in the FADS, ACTN3, EDAR genes) shows the ambiguity of the testing results, which may be due to the loss of some traces of the "Beringian" adaptation in the gene pools of modern Native Americans. The most optimal strategy for further research seems to be the search for adaptive variant.

Two mutations at KRT74 and EDAR synergistically drive the fine-wool production in Chinese sheep

IntroductionFine-wool sheep are the most common breed used by the wool industry worldwide. Fine-wool sheep have over a three-fold higher follicle density and a 50% smaller fiber diameter than coarse-wool sheep. ObjectivesThis study aims to clarify the underlying genetic basis for the denser and finer wool phenotype in fine-wool breeds. MethodWhole-genome sequences of 140 samples, Ovine HD630K SNP array data of 385 samples, including fine, semi-fine, and coarse wool sheep, as well as skin transcriptomes of nine samples were integrated for genomic selection signature analysis. ResultsTwo loci at keratin 74 (KRT74) and ectodysplasin receptor (EDAR) were revealed. Fine-scale analysis in 250 fine/semi-fine and 198 coarse wool sheep narrowed this association to one C/A missense variant of KRT74 (OAR3:133,486,008, P = 1.02E-67) and one T/C SNP in the regulatory region upstream of EDAR (OAR3:61,927,840, P = 2.50E-43). Cellular over-expression and ovine skin section staining assays confirmed that C-KRT74 activated the KRT74 protein and specifically enlarged cell size at the Huxley’s layer of the inner root sheath (P < 0.01). This structure enhancement shapes the growing hair shaft into the finer wool than the wild type. Luciferase assays validated that the C-to-T mutation upregulated EDAR mRNA expression via a newly created SOX2 binding site and potentially led to the formation of more hair placodes. ConclusionsTwo functional mutations driving finer and denser wool production were characterized and offered new targets for genetic breeding during wool sheep selection. This study not only provides a theoretical basis for future selection of fine wool sheep breeds but also contributes to improving the value of wool commodities.

Dental Phenotype with Minor Ectodermal Symptoms Suggestive of WNT10A Deficiency

Ectodermal dysplasias (EDs) represent a heterogeneous group of genetic disorders characterized by the abnormal development of ectodermal-derived tissues. They include the involvement of the hair, nails, skin, sweat glands, and teeth. Pathogenic variants in EDA1 (Xq12-13.1; OMIM*300451), EDAR (2q11-q13; OMIM*604095), EDARADD (1q42-q43, OMIM*606603), and WNT10A (2q35; OMIM*606268) genes are responsible for most EDs. Bi-allelic pathogenic variants of WNT10A have been associated with autosomal recessive forms of ED, as well as non-syndromic tooth agenesis (NSTA). The potential phenotypic impact of associated modifier mutations in other ectodysplasin pathway genes has also been pointed out. We present on an 11-year-old Chinese boy with oligodontia, with conical-shaped teeth as the main phenotype, and other very mild ED signs. The genetic study identified the pathogenic variants WNT10A (NM_025216.3): c.310C > T; p. (Arg104Cys) and c.742C > T; p. (Arg248Ter) in compound heterozygosis, confirmed by parental segregation. In addition, the patient had the polymorphism EDAR (NM_022336.4): c.1109T > C, p. (Val370Ala) in homozygosis, named EDAR370. A prominent dental phenotype with minor ectodermal symptoms is very suggestive of WNT10A mutations. In this case, the EDAR370A allele might also attenuate the severity of other ED signs.

THE ROLE OF ADAPTIVE VARIANTS OF THE EDAR GENE IN THE DEVELOPMENT OF BREAST CANCER. (Abstracts of the report at the scientific and practical conference "Molecular and biological mechanisms of human health formation in the North" on November 17–18, 2022, Yakutsk)

There are suggestions in the literature about the involvement of the 370A EDAR allele in the development of breast cancer. Unfortunately, the question of what the frequency of the allele is among patients with breast cancer has not been clarified, and studies, even using the case-control method, have not been conducted to clarify the role of this mutation in its development. It is unclear what role the 370A mutation of the EDAR gene plays in the low incidence of breast cancer in Yakut women.

A novel EDAR variant identified in non-syndromic tooth agenesis: Insights from molecular dynamics

ObjectiveThis study aims to investigate a novel pathogenic variant in a Chinese family of non-syndromic tooth agenesis (NSTA) and study the impact of the variant on related protein and pathway. DesignOne NSTA family was collected. Whole exome sequencing and Sanger sequencing were performed on the proband with NSTA and his 5 family members. The pathogenic influence of the mutant is evaluated by bioinformatics analyses including evolutionary conservation analysis and secondary structure prediction. Molecular dynamics (MD) simulations and binding free energy calculations were then performed to explore changes in the tertiary structure and binding ability of the protein. ResultsWe found a novel missense ectodysplasin A receptor (EDAR) variant (c .1292 T > G; p.Ile431Arg) in all affected family members. The results of bioinformatics analyses revealed that the EDAR had harmful changes after mutation. MD simulations and the binding free energy calculations results showed that the mutant EDAR protein and EDAR/ectodysplasin-A receptor-associated adapter (EDARADD) complex displayed tertiary structural change, and EDAR possessed a lower affinity to EDARADD after mutation. ConclusionsWe found a novel EDAR variant (c.1292 T > G; p.Ile431Arg) in one NSTA family, which affects the binding of EDAR and EDARADD.

A novel mutation in the collagen domain of EDA results in hypohidrotic ectodermal dysplasia by impacting the receptor-binding capability.

Hypohidrotic ectodermal dysplasia (HED) mainly results from gene mutations in the EDA/EDAR/NF-κB pathway. Function analysis of the mutations in the collagen domain of ectodysplasin A (EDA)result in HED has been rarely studied. This study aimed at determining the mechanism by which the novel collagen domain mutation of EDA results in HED. We analyzed the DNAs from a Chinese family with HED and performed bioinformatics analysis. A new three-dimensional structure model of the EDA trimer was built and used to predict the effect of the mutations on EDA. We performed a western blot to detect EDA1 proteins in cell lysates and supernatants. We then performed coimmunoprecipitation to determine whether the mutation would affect the interaction of EDA1 with the EDA receptor (EDAR). Dual luciferase reporter assay and immunofluorescence were performed to detect the effect of the mutant EDA1 protein on nuclear factor kappa B (NF-κB) activation. A novel missense mutation (c.593G > A, p. Gly198Glu) in the collagen domain of EDA was detected. The mutation was predicted to be disease-causing. A three-dimensional structure model of the EDA trimer was first built in this study, in which the mutation site is located around the receptor binding domain. Functional studies showed that there was no difference in the secretion activity between the mutant EDA1 and the wild-type EDA1. However, the receptor-binding activity and the transcription activation of NF-κB were impaired by the mutation. We identified a novel mutation (c.593G > A, p. Gly198Glu) in the collagen domain of EDA. Bioinformatics analysis and functional studies showed this mutation was damaging, indicating that mutations in the collagen domain of EDA could result in HED by affecting the receptor-binding activity of EDA and the transcriptional activity of NF-κB.

Different degree of loss-of-function among four missense mutations in the EDAR gene responsible for autosomal recessive hypohidrotic ectodermal dysplasia may be associated with the phenotypic severity.

Hypohidrotic ectodermal dysplasia is a rare condition characterized by hypohidrosis, hypodontia, and hypotrichosis. The disease can show X-linked recessive, autosomal dominant or autosomal recessive inheritance trait. Of these, the autosomal forms are caused by mutations in either EDAR or EDARADD. To date, the underlying pathomechanisms or genotype-phenotype correlations for autosomal forms have not completely been disclosed. In this study, we performed a series of in vitro studies for four missense mutations in the death domain of EDAR protein: p.R358Q, p.G382S, p.I388T, and p.T403M. The results revealed that p.R358Q- and p.T403M-mutant EDAR showed different expression patterns from wild-type EDAR in both western blots and immunostainings. NF-κB reporter assays demonstrated that all the mutant EDAR showed reduced activation of NF-κB, but the reduction by p.G382S- and p.I388T-mutant EDAR was moderate. Co-immunoprecipitation assays showed that p.R358Q- and p.T403M-mutant EDAR did not bind with EDARADD at all, whereas p.G382S- and p.I388T-mutant EDAR maintained the affinity to some extent. Furthermore, we demonstrated that all the mutant EDAR proteins analyzed aberrantly bound with TRAF6. Sum of the data suggest that the degree of loss-of-function is different among the mutant EDAR proteins, which may be associated with the severity of the disease.

The matrilineal ancestry of Nepali populations.

The Tibetan plateau and high mountain ranges of Nepal are one of the challenging geographical regions inhabited by modern humans. While much of the ethnographic and population-based genetic studies were carried out to investigate the Tibetan and Sherpa highlanders, little is known about the demographic processes that enabled the colonization of the hilly areas of Nepal. Thus, the present study aimed to investigate the past demographic events that shaped the extant Nepalese genetic diversity using mitochondrial DNA (mtDNA) variations from ethnic Nepalese groups. We have analyzed mtDNA sequences of 999 Nepalese and compared data with 38,622 published mtDNA sequences from rest of the world. Our analysis revealed that the genomic landscapes of prehistoric Himalayan settlers of Nepal were similar to that of the low-altitude extant Nepalese (LAN), especially Newar and Magar population groups, but differ from contemporary high-altitude Sherpas. LAN might have derived their East Eurasian ancestry mainly from low-altitude Tibeto-Burmans, who likely have migrated from East Asia and assimilated across the Eastern Himalayas extended from the Eastern Nepal to the North-East of India, Bhutan, Tibet and Northern Myanmar. We also identified a clear genetic sub-structure across different ethnic groups of Nepal based on mtDNA haplogroups and ectodysplasin-A receptor (EDAR) gene polymorphism. Our comprehensive high-resolution mtDNA-based genetic study of Tibeto-Burman communities reconstructs the maternal origins of prehistoric Himalayan populations and sheds light on migration events that have brought most of the East Eurasian ancestry to the present-day Nepalese population.

Ectodysplasin A1 Deficiency Leads to Osteopetrosis-like Changes in Bones of the Skull Associated with Diminished Osteoclastic Activity.

Pathogenic variants of the gene Eda cause X-linked hypohidrotic ectodermal dysplasia (XLHED), which is characterized by structural abnormalities or lack of ectodermal appendages. Signs of dysplasia are not restricted to derivatives of the ectodermal layer, but mesodermal abnormalities, such as craniofacial dysmorphism, are also frequently observed, suggesting close reciprocal interactions between the ectoderm and mesoderm; however, a causal link has remained unsubstantiated. We investigated the functional impact of defective ectodysplasin A1 (Eda1) signaling on postnatal bone homeostasis in Eda1-deficient Tabby mice. Interestingly, Eda1 was detected in wild-type mouse calvariae throughout postnatal lifetime. In calvariae, bone-lining Osterix (Osx)+ osteoblasts stained positive for Eda1, and osteoclasts were revealed as Eda receptor (Edar)-positive. Moreover, adult Eda1-deficient calvarial bone showed osteopetrosis-like changes with significantly diminished marrow space, which was maintained during adulthood. Concomitantly with osteopetrosis-like changes, Tabby calvarial bone and Tabby bone marrow-derived osteoclasts had far less osteoclastic activity-associated co-enzymes including cathepsin K, Mmp9, Trap, and Tcirg1 (V-type proton ATPase a3 subunit) compared with wild-type calvariae in vivo or osteoclasts in vitro, indicating that Eda1 deficiency may affect the activity of osteoclasts. Finally, we confirmed that nuclear Nfatc1-positive osteoclasts were strongly diminished during mature osteoclastic differentiation under M-CSF and RANKL in the Tabby model, while Fc-EDA treatment of Tabby-derived osteoclasts significantly increased nuclear translocation of Nfatc1. Furthermore, we identified enhanced Nfatc1 and NF-κB transcriptional activity following Fc-EDA treatment in vitro using luciferase assays. Overall, the results indicate that diminished expressions of osteoclastic activity-associated co-enzymes may lead to disturbed bone homeostasis in Tabby calvariae postnatally.

WNT10A variants: following the pattern of inheritance in tooth agenesis and self-reported family history of cancer.

The aim of this study was the analysis of WNT10A variants in seven families of probands with various forms of tooth agenesis and self-reported family history of cancer. We enrolled 60 young subjects (aged 13 to 17) from the Czech Republic with various forms of tooth agenesis. Dental phenotypes were assessed using Planmeca ProMax 3D (Planmeca Oy, Finland) with Planmeca Romexis software (version 2.9.2) together with oral examinations. After screening PAX9, MSX1, EDA, EDAR, AXIN2 and WNT10A genes on the Illumina MiSeq platform (Illumina, USA), we further analyzed the evolutionarily highly conserved WNT10A gene by capillary sequencing in the seven families. All the detected variants were heterozygous or compound heterozygous with various levels of phenotypic expression. The most severe phenotype (oligodontia) was found in a proband who was compound heterozygous for the previously identified WNT10A variant p.Phe228Ile and a newly discovered c.748G > A variant (p.Gly250Arg) of WNT10A. The newly identified variant causes substitution of hydrophobic glycine for hydrophilic arginine. We suggest that the amino acid changes in otherwise highly conserved sequences significantly affect the dental phenotype. No relationship between the presence of WNT10A variants and a risk of cancer has been found. Screening of PAX9, MSX1, EDA, EDAR, AXIN2 and WNT10A genes in hope to elucidate the pattern of inheritance in families.

Functional and clinical analysis of five EDA variants associated with ectodermal dysplasia but with a hard-to-predict significance.

Deficiency of ectodysplasin A1 (EDA1) due to variants of the gene EDA causes X-linked hypohidrotic ectodermal dysplasia (XLHED), a rare genetic condition characterized by abnormal development of ectodermal structures. XLHED is defined by the triad of hypotrichosis, hypo- or anhidrosis, and hypo- or anodontia. Anhidrosis may lead to life-threatening hyperthermia. A definite genetic diagnosis is, thus, important for the patients’ management and amenability to a novel prenatal treatment option. Here, we describe five familial EDA variants segregating with the disease in three families, for which different prediction tools yielded discordant results with respect to their significance. Functional properties in vitro and levels of circulating serum EDA were compared with phenotypic data on skin, hair, eyes, teeth, and sweat glands. EDA1-Gly176Val, although associated with relevant hypohidrosis, still bound to the EDA receptor (EDAR). Subjects with EDA1-Pro389LeufsX27, -Ter392GlnfsX30, -Ser125Cys, and an EDA1 splice variant (c.924+7A > G) showed complete absence of pilocarpine-induced sweating. EDA1-Pro389LeufsX27 was incapable of binding to EDAR and undetectable in serum. EDA1-Ter392GlnfsX30, produced in much lower amounts than wild-type EDA1, could still bind to EDAR, and so did EDA1-Ser125Cys that was, however, undetectable in serum. The EDA splice variant c.924+7A > G resulted experimentally in a mix of wild-type EDA1 and EDA molecules truncated in the middle of the receptor-binding domain, with reduced EDA serum concentration. Thus, in vitro assays reflected the clinical phenotype in two of these difficult cases, but underestimated it in three others. Absence of circulating EDA seems to predict the full-blown phenotype of XLHED, while residual EDA levels may also be found in anhidrotic patients. This indicates that unborn subjects carrying variants of uncertain significance could benefit from an upcoming prenatal medical treatment even if circulating EDA levels or tests in vitro suggest residual EDA1 activity.