Familiar Disposition of May-Thurner Syndrome-A Case Series.

May-Thurner syndrome is a venous compression syndrome of the pelvic vessels that represents a relevant risk factor for thrombus formation. The standard procedure to secure a diagnosis is venography, followed by endovascular therapy as the preferred treatment choice if the patient is symptomatic. In our case series, there are three related patients with May-Thurner syndrome. A 16-year-old female was admitted with pulmonary embolism, dyspnoea and hip pain. The compression syndrome was diagnosed with interventional venography, and the patient received venous stent implantation. Due to her family history, we also suspected her mother to be affected by the syndrome and elucidated the diagnosis shortly afterwards by invasive venography. Subsequently, we examined the patient's 19-year-old brother, and magnetic resonance imaging confirmed May-Thurner syndrome. A similar case series has not been published before. In this case, the family relation indicates a possible hereditary aspect of May-Thurner syndrome. This hypothesis should be the subject of further research. In conclusion, it is essential to assess family history thoroughly when treating patients with May-Thurner syndrome.

Identification of de novo variants in nonsyndromic cleft lip with/without cleft palate patients with low polygenic risk scores.

BACKGROUND: Nonsyndromic cleft lip with/without cleft palate (nsCL/P) is a congenital malformation of multifactorial etiology. Research has identified >40 genome-wide significant risk loci, which explain less than 40% of nsCL/P heritability. Studies show that some of the hidden heritability is explained by rare penetrant variants. METHODS: To identify new candidate genes, we searched for highly penetrant de novo variants (DNVs) in 50 nsCL/P patient/parent-trios with a low polygenic risk for the phenotype (discovery). We prioritized DNV-carrying candidate genes from the discovery for resequencing in independent cohorts of 1010 nsCL/P patients of diverse ethnicities and 1574 population-matched controls (replication). Segregation analyses and rare variant association in the replication cohort, in combination with additional data (genome-wide association data, expression, protein-protein-interactions), were used for final prioritization. CONCLUSION: In the discovery step, 60 DNVs were identified in 60 genes, including a variant in the established nsCL/P risk gene CDH1. Re-sequencing of 32 prioritized genes led to the identification of 373 rare, likely pathogenic variants. Finally, MDN1 and PAXIP1 were prioritized as top candidates. Our findings demonstrate that DNV detection, including polygenic risk score analysis, is a powerful tool for identifying nsCL/P candidate genes, which can also be applied to other multifactorial congenital malformations.

Bitterless guaifenesin prodrugs-design, synthesis, characterization, in vitro kinetics, and bitterness studies.

A respected number of drugs suffer from bitter taste which results in patient incompliance. With the aim of solving the bitterness of guaifenesin, dimethyl maleate, maleate, glutarate, succinate, and dimethyl succinate prodrugs were designed and synthesized. Molecular orbital methods were utilized for the design of the ester prodrugs. The density functional theory (DFT) calculations revealed that the hydrolysis efficiency of the synthesized prodrugs is significantly sensitive to the pattern of substitution on C=C bond and distance between the nucleophile and the electrophile. The hydrolysis of the prodrugs was largely affected by the pH of the medium. The experimental t1/2 for the hydrolysis of guaifenesin dimaleate ester prodrugs in 1N HCl was the least and for guaifenesin dimethyl succinate was the highest. Functional heterologous expression of TAS2R14, a broadly tuned bitter taste receptor responding to guaifenesin, and experiments using these prodrugs revealed that, while some of the prodrugs still activated the receptor similarly or even stronger than the parent substance, succinate derivatization resulted in the complete loss of receptor responses. The predicted binding modes of guaifenesin and its prodrugs to the TAS2R14 homology model suggest that the decreased activity of the succinate derivatives may be caused by a clash with Phe247.

Reengineering the ligand sensitivity of the broadly tuned human bitter taste receptor TAS2R14.

BACKGROUND: In humans, bitterness perception is mediated by ~25 bitter taste receptors present in the oral cavity. Among these receptors three, TAS2R10, TAS2R14 and TAS2R46, exhibit extraordinary wide agonist profiles and hence contribute disproportionally high to the perception of bitterness. Perhaps the most broadly tuned receptor is the TAS2R14, which may represent, because of its prominent expression in extraoral tissues, a receptor of particular importance for the physiological actions of bitter compounds beyond taste. METHODS: To investigate how the architecture and composition of the TAS2R14 binding pocket enables specific interactions with a complex array of chemically diverse bitter agonists, we carried out homology modeling and ligand docking experiments, subjected the receptor to point-mutagenesis of binding site residues and performed functional calcium mobilization assays. RESULTS: In total, 40 point-mutated receptor constructs were generated to investigate the contribution of 19 positions presumably located in the receptor's binding pocket to activation by 7 different TAS2R14 agonists. All investigated positions exhibited moderate to pronounced agonist selectivity. CONCLUSIONS: Since numerous modifications of the TAS2R14 binding pocket resulted in improved responses to individual agonists, we conclude that this bitter taste receptor might represent a suitable template for the engineering of the agonist profile of a chemoreceptive receptor. GENERAL SIGNIFICANCE: The detailed structure-function analysis of the highly promiscuous and widely expressed TAS2R14 suggests that this receptor must be considered as potentially frequent target for known and novel drugs including undesired off-effects.

Nonsyndromic cleft palate: An association study at GWAS candidate loci in a multiethnic sample.

BACKGROUND: Nonsyndromic cleft palate only (nsCPO) is a common and multifactorial form of orofacial clefting. In contrast to successes achieved for the other common form of orofacial clefting, that is, nonsyndromic cleft lip with/without cleft palate (nsCL/P), genome wide association studies (GWAS) of nsCPO have identified only one genome wide significant locus. Aim of the present study was to investigate whether common variants contribute to nsCPO and, if so, to identify novel risk loci. METHODS: We genotyped 33 SNPs at 27 candidate loci from 2 previously published nsCPO GWAS in an independent multiethnic sample. It included: (i) a family-based sample of European ancestry (n = 212); and (ii) two case/control samples of Central European (n = 94/339) and Arabian ancestry (n = 38/231), respectively. A separate association analysis was performed for each genotyped dataset, and meta-analyses were performed. RESULTS: After association analysis and meta-analyses, none of the 33 SNPs showed genome-wide significance. Two variants showed nominally significant association in the imputed GWAS dataset and exhibited a further decrease in p-value in a European and an overall meta-analysis including imputed GWAS data, respectively (rs395572: PMetaEU = 3.16 × 10-4 ; rs6809420: PMetaAll = 2.80 × 10-4 ). CONCLUSION: Our findings suggest that there is a limited contribution of common variants to nsCPO. However, the individual effect sizes might be too small for detection of further associations in the present sample sizes. Rare variants may play a more substantial role in nsCPO than in nsCL/P, for which GWAS of smaller sample sizes have identified genome-wide significant loci. Whole-exome/genome sequencing studies of nsCPO are now warranted.

Sequencing the GRHL3 Coding Region Reveals Rare Truncating Mutations and a Common Susceptibility Variant for Nonsyndromic Cleft Palate.

Nonsyndromic cleft lip with/without cleft palate (nsCL/P) and nonsyndromic cleft palate only (nsCPO) are the most frequent subphenotypes of orofacial clefts. A common syndromic form of orofacial clefting is Van der Woude syndrome (VWS) where individuals have CL/P or CPO, often but not always associated with lower lip pits. Recently, ∼5% of VWS-affected individuals were identified with mutations in the grainy head-like 3 gene (GRHL3). To investigate GRHL3 in nonsyndromic clefting, we sequenced its coding region in 576 Europeans with nsCL/P and 96 with nsCPO. Most strikingly, nsCPO-affected individuals had a higher minor allele frequency for rs41268753 (0.099) than control subjects (0.049; p = 1.24 × 10(-2)). This association was replicated in nsCPO/control cohorts from Latvia, Yemen, and the UK (pcombined = 2.63 × 10(-5); ORallelic = 2.46 [95% CI 1.6-3.7]) and reached genome-wide significance in combination with imputed data from a GWAS in nsCPO triads (p = 2.73 × 10(-9)). Notably, rs41268753 is not associated with nsCL/P (p = 0.45). rs41268753 encodes the highly conserved p.Thr454Met (c.1361C>T) (GERP = 5.3), which prediction programs denote as deleterious, has a CADD score of 29.6, and increases protein binding capacity in silico. Sequencing also revealed four novel truncating GRHL3 mutations including two that were de novo in four families, where all nine individuals harboring mutations had nsCPO. This is important for genetic counseling: given that VWS is rare compared to nsCPO, our data suggest that dominant GRHL3 mutations are more likely to cause nonsyndromic than syndromic CPO. Thus, with rare dominant mutations and a common risk variant in the coding region, we have identified an important contribution for GRHL3 in nsCPO.

Probing the Binding Pocket of the Broadly Tuned Human Bitter Taste Receptor TAS2R14 by Chemical Modification of Cognate Agonists.

Sensing potentially harmful bitter substances in the oral cavity is achieved by a group of (˜) 25 receptors, named TAS2Rs, which are expressed in specialized sensory cells and recognize individual but overlapping sets of bitter compounds. The receptors differ in their tuning breadths ranging from narrowly to broadly tuned receptors. One of the most broadly tuned human bitter taste receptors is the TAS2R14 recognizing an enormous variety of chemically diverse synthetic and natural bitter compounds, including numerous medicinal drugs. This suggests that this receptor possesses a large readily accessible ligand binding pocket. To allow probing the accessibility and size of the ligand binding pocket, we chemically modified cognate agonists and tested receptor responses in functional assays. The addition of large functional groups to agonists was usually possible without abolishing agonistic activity. The newly synthesized agonist derivatives were modeled in the binding site of the receptor, providing comparison to the mother substances and rationalization of the in vitro activities of this series of compounds.

Evaluating eight newly identified susceptibility loci for nonsyndromic cleft lip with or without cleft palate in a Mesoamerican population.

BACKGROUND: Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is among the most frequently occurring congenital malformations worldwide. The number of genetic loci identified as being involved in NSCL/P etiology was recently increased by a large genome-wide meta-analysis of European and Asian samples. This meta-analysis confirmed all six previously recognized genetic susceptibility loci and identified six novel ones. METHODS: To investigate which of these 12 loci contribute to NSCL/P risk in an independent sample of distinct ethnicity, we performed a case-control association analysis in a sample of the Mesoamerican population. A total of 153 individuals with NSCL/P (cases) and 337 unaffected controls were included. Top single-nucleotide polymorphisms (SNPs) at 8 of the 12 loci (1p22.1, 1p36, 2p21, 3p11.1, 8q21.3, 13q31.1, 15q22, and 20q12) were analyzed using mass spectroscopy and restriction-length-fragment polymorphism analyses. In a previous study, we had analyzed the remaining four NSCL/P susceptibility regions (IRF6, 8q24, 10q25, and 17q22) in the same sample. RESULTS: Single-marker association analyses applying allelic, dominant, and recessive models revealed nominal significant associations for four of the eight loci, with two additional loci showing at least a trend of association in the hypothesized direction. CONCLUSION: In combination with results from our previous study using the same sample, our data suggest that the majority of the known NSCL/P susceptibility regions identified to date also confer risk for this malformation in the Mesoamerican population. Birth Defects Research (Part A) 100:43-47, 2014. © 2013 Wiley Periodicals, Inc.

The bitter pill: clinical drugs that activate the human bitter taste receptor TAS2R14.

Bitter taste receptors (TAS2Rs) mediate aversive response to toxic food, which is often bitter. These G-protein-coupled receptors are also expressed in extraoral tissues, and emerge as novel targets for therapeutic indications such as asthma and infection. Our goal was to identify ligands of the broadly tuned TAS2R14 among clinical drugs. Molecular properties of known human bitter taste receptor TAS2R14 agonists were incorporated into pharmacophore- and shape-based models and used to computationally predict additional ligands. Predictions were tested by calcium imaging of TAS2R14-transfected HEK293 cells. In vitro testing of the virtual screening predictions resulted in 30-80% success rates, and 15 clinical drugs were found to activate the TAS2R14. hERG potassium channel, which is predominantly expressed in the heart, emerged as a common off-target of bitter drugs. Despite immense chemical diversity of known TAS2R14 ligands, novel ligands and previously unknown polypharmacology of drugs were unraveled by in vitro screening of computational predictions. This enables rational repurposing of traditional and standard drugs for bitter taste signaling modulation for therapeutic indications.

Resequencing of VAX1 in patients with nonsyndromic cleft lip with or without cleft palate.

BACKGROUND: Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is one of the most common of all congenital anomalies, and has a multifactorial etiology involving both environmental and genetic factors. Recent genome-wide association studies (GWAS) identified strong association between a locus on chromosome 10q25.3 and NSCL/P in European samples. One gene at 10q25.3, the ventral anterior homeobox 1 (VAX1) gene, is considered a strong candidate gene for craniofacial malformations. The purpose of the present study was to provide further evidence that VAX1 is the causal gene at the 10q25.3 locus through identification of an excess of rare mutations in patients with NSCL/P. METHODS: The 5'UTR, complete coding regions, and adjacent splice sites of the two known VAX1 isoforms were sequenced in 384 patients with NSCL/P and 384 controls of Central European descent. Observed variants were investigated with respect to familial cosegregation or de novo occurrence, and in silico analyses were performed to identify putative effects on the transcript or protein level. RESULTS: Eighteen single-base variants were found, 15 of them rare and previously unreported. In the long VAX1 isoform, predicted functionally relevant variants were observed more often in NSCL/P cases, although this difference was not significant (p = 0.17). Analysis of family members demonstrated incomplete cosegregation in most pedigrees. CONCLUSION: Our data do not support the hypothesis that highly penetrant rare variants in VAX1 are a cause of NSCL/P. To determine whether VAX1 is the causative gene at 10q25.3 further research, in particular into the biologic function of its long isoform, is warranted. Birth Defects Research (Part A), 2012.

Evaluating SKI as a candidate gene for non-syndromic cleft lip with or without cleft palate.

Non-syndromic cleft lip with or without cleft palate (NSCL/P) is one of the most common of all congenital malformations and has a multifactorial etiology. Findings in mice suggest that the v-ski sarcoma viral oncogene homolog (SKI) gene is a candidate gene for orofacial clefting. In humans, a significant association between rs2843159 within SKI and NSCL/P has been reported in patients from the Philippines and South America. In the South American patients, the association was driven by the subgroup of patients with non-syndromic cleft lip only (NSCLO). Here we investigated the association with rs2843159 in a Mayan Mesoamerican population (172 NSCL/P patients and 366 controls). In addition, we analyzed the phenotypic subgroups NSCLO and non-syndromic cleft of lip and palate (NSCLP). A trend towards association between rs2843159 and NSCL/P was observed in the Mayan cohort (P = 0.097), and we found a stronger association in the NSCLP subgroup (P = 0.072) despite a limited sample size. To investigate whether other common variants within the SKI gene contribute to NSCL/P susceptibility in European and Asian populations, we also analyzed genotypic data from two recent genome-wide association studies using set-based statistical approaches. These analyses detected a trend toward association in the European population. Our data provide limited support for the hypothesis that common SKI variants are susceptibility factors for NSCL/P.

Genome-wide meta-analyses of nonsyndromic cleft lip with or without cleft palate identify six new risk loci.

We have conducted the first meta-analyses for nonsyndromic cleft lip with or without cleft palate (NSCL/P) using data from the two largest genome-wide association studies published to date. We confirmed associations with all previously identified loci and identified six additional susceptibility regions (1p36, 2p21, 3p11.1, 8q21.3, 13q31.1 and 15q22). Analysis of phenotypic variability identified the first specific genetic risk factor for NSCLP (nonsyndromic cleft lip plus palate) (rs8001641; P(NSCLP) = 6.51 × 10(-11); homozygote relative risk = 2.41, 95% confidence interval (CI) 1.84-3.16).

Genetic determination of human facial morphology: links between cleft-lips and normal variation.

Recent genome-wide association studies have identified single nucleotide polymorphisms (SNPs) associated with non-syndromic cleft lip with or without cleft palate (NSCL/P), and other previous studies showed distinctly differing facial distance measurements when comparing unaffected relatives of NSCL/P patients with normal controls. Here, we test the hypothesis that genetic loci involved in NSCL/P also influence normal variation in facial morphology. We tested 11 SNPs from 10 genomic regions previously showing replicated evidence of association with NSCL/P for association with normal variation of nose width and bizygomatic distance in two cohorts from Germany (N=529) and the Netherlands (N=2497). The two most significant associations found were between nose width and SNP rs1258763 near the GREM1 gene in the German cohort (P=6 × 10(-4)), and between bizygomatic distance and SNP rs987525 at 8q24.21 near the CCDC26 gene (P=0.017) in the Dutch sample. A genetic prediction model explained 2% of phenotype variation in nose width in the German and 0.5% of bizygomatic distance variation in the Dutch cohort. Although preliminary, our data provide a first link between genetic loci involved in a pathological facial trait such as NSCL/P and variation of normal facial morphology. Moreover, we present a first approach for understanding the genetic basis of human facial appearance, a highly intriguing trait with implications on clinical practice, clinical genetics, forensic intelligence, social interactions and personal identity.

FAF1, a gene that is disrupted in cleft palate and has conserved function in zebrafish.

Cranial neural crest (CNC) is a multipotent migratory cell population that gives rise to most of the craniofacial bones. An intricate network mediates CNC formation, epithelial-mesenchymal transition, migration along distinct paths, and differentiation. Errors in these processes lead to craniofacial abnormalities, including cleft lip and palate. Clefts are the most common congenital craniofacial defects. Patients have complications with feeding, speech, hearing, and dental and psychological development. Affected by both genetic predisposition and environmental factors, the complex etiology of clefts remains largely unknown. Here we show that Fas-associated factor-1 (FAF1) is disrupted and that its expression is decreased in a Pierre Robin family with an inherited translocation. Furthermore, the locus is strongly associated with cleft palate and shows an increased relative risk. Expression studies show that faf1 is highly expressed in zebrafish cartilages during embryogenesis. Knockdown of zebrafish faf1 leads to pharyngeal cartilage defects and jaw abnormality as a result of a failure of CNC to differentiate into and express cartilage-specific markers, such as sox9a and col2a1. Administration of faf1 mRNA rescues this phenotype. Our findings therefore identify FAF1 as a regulator of CNC differentiation and show that it predisposes humans to cleft palate and is necessary for lower jaw development in zebrafish.

SUMO1 as a candidate gene for non-syndromic cleft lip with or without cleft palate: no evidence for the involvement of common or rare variants in Central European patients.

OBJECTIVE: Studies in mice and humans have suggested that SUMO1, which codes for the small ubiquitin-related modifier 1 (SUMO1), is a promising candidate gene for non-syndromic cleft lip with or without cleft palate (NSCL/P). To investigate the possible involvement of this gene in NSCL/P patients from Central Europe, we performed: (i) a case control association study, and (ii) a resequencing study. METHODS: Genotyping and the subsequent single marker and haplotype association analyses were performed for 413 NSCL/P patients and 412 controls. A total of 17 tagging single-nucleotide polymorphisms (SNPs) were used. In the resequencing study, the complete coding region and splice sites were sequenced in 65 index patients from multiply affected families. RESULTS: One of the 17 tested SNPs (rs16838917) had a borderline significant P-value of 0.0416 in the single-marker association analysis. However, this result did not withstand correction for multiple testing (P(corr)=0.707). No association was observed for any haplotypic marker combination. Sequencing failed to identify any novel rare sequence variants. CONCLUSIONS: The results of the present study do not support the hypothesis that common or rare variants in SUMO1 play a significant role in the development of NSCL/P in Central-European patients. However, smaller effects of common variants or the presence of rare high penetrance mutations in other non-investigated familial cases cannot be excluded. Further analysis of SUMO1 in independent samples from Central European and other populations is therefore warranted.

Genetic risk factors for nonsyndromic cleft lip with or without cleft palate in a Mesoamerican population: Evidence for IRF6 and variants at 8q24 and 10q25.

INTRODUCTION: Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is one of the most common of all birth defects. NSCL/P has a multifactorial etiology that includes both genetic and environmental factors. The IRF6 gene and three further susceptibility loci at 8q24, 10q25, and 17q22, which were identified by a recent genome-wide association scan (GWAS), are confirmed genetic risk factors for NSCL/P in patients of European descent. METHODS: A case-control association study was performed to investigate whether these four risk loci contribute to NSCL/P in a Mesoamerican population using four single nucleotide polymorphisms to represent IRF6 and the three novel susceptibility loci. A total of 149 NSCL/P patients and 303 controls of Mayan origin were included. RESULTS: Single marker analysis revealed a significant association between NSCL/P and risk variants in IRF6 and the 8q24 and 10q25 loci. In contrast to previous findings, the association at the 8q24 locus was driven solely by homozygote carriers of the risk allele. This suggests that this locus might act in a recessive manner in the Mayan population. No evidence for association was found at the 17q22 locus. This may have been attributable to the limited power of the sample. CONCLUSION: These results suggest that IRF6 and the 10q25 and 8q24 loci confer a risk for the development of NSCL/P in persons of Mayan origin.

Establishment of a mouse model with misregulated chromosome condensation due to defective Mcph1 function.

Mutations in the human gene MCPH1 cause primary microcephaly associated with a unique cellular phenotype with premature chromosome condensation (PCC) in early G2 phase and delayed decondensation post-mitosis (PCC syndrome). The gene encodes the BRCT-domain containing protein microcephalin/BRIT1. Apart from its role in the regulation of chromosome condensation, the protein is involved in the cellular response to DNA damage. We report here on the first mouse model of impaired Mcph1-function. The model was established based on an embryonic stem cell line from BayGenomics (RR0608) containing a gene trap in intron 12 of the Mcph1 gene deleting the C-terminal BRCT-domain of the protein. Although residual wild type allele can be detected by quantitative real-time PCR cell cultures generated from mouse tissues bearing the homozygous gene trap mutation display the cellular phenotype of misregulated chromosome condensation that is characteristic for the human disorder, confirming defective Mcph1 function due to the gene trap mutation. While surprisingly the DNA damage response (formation of repair foci, chromosomal breakage, and G2/M checkpoint function after irradiation) appears to be largely normal in cell cultures derived from Mcph1(gt/gt) mice, the overall survival rates of the Mcph1(gt/gt) animals are significantly reduced compared to wild type and heterozygous mice. However, we could not detect clear signs of premature malignant disease development due to the perturbed Mcph1 function. Moreover, the animals show no obvious physical phenotype and no reduced fertility. Body and brain size are within the range of wild type controls. Gene expression on RNA and protein level did not reveal any specific pattern of differentially regulated genes. To the best of our knowledge this represents the first mammalian transgenic model displaying a defect in mitotic chromosome condensation and is also the first mouse model for impaired Mcph1-function.