Serotype b of Aggregatibacter actinomycetemcomitans increases osteoclast and memory T-lymphocyte activation

During periodontitis, alveolar bone resorption is associated with activation of T helper type 17 (Th17) lymphocytes and receptor activator of nuclear factor-κB ligand (RANKL) -induced osteoclasts. We previously reported that serotype b of Aggregatibacter actinomycetemcomitans has a higher capacity to trigger Th17-type differentiation and function in activated T lymphocytes and its lipopolysaccharide is a more potent immunogen compared with the other serotypes. This study aimed to investigate whether serotype b of A. actinomycetemcomitans induces higher Th17-associated RANKL production, RANKL-induced osteoclast activation, and antigen-specific memory T lymphocyte proliferation. On naive CD4(+) T lymphocytes stimulated with autologous dendritic cells primed with different A. actinomycetemcomitans serotypes, RANKL production, T-bet, GATA-3, RORC2 and Foxp3 expression, RORC2/RANKL intracellular double-expression, TRAP(+) osteoclast activation, and bone resorption were quantified. The frequency of proliferating memory T lymphocytes in response to A. actinomycetemcomitans serotypes was determined in periodontitis and healthy subjects. Naive CD4(+) T lymphocytes stimulated by serotype b-primed dendritic cells elicited higher levels of RANKL, RORC2, TRAP(+) osteoclasts, and bone resorption than the same cells stimulated with the other serotypes. RANKL positively correlated and co-expressed with RORC2. Memory T lymphocytes responding to serotype b were more frequently detected in periodontitis patients than healthy subjects. These results indicate that serotype b of A. actinomycetemcomitans is associated with higher production of RANKL and these increased levels are associated with Th17 lymphocyte induction, osteoclast activation, and bone resorption.

Poly(ethylene oxide) functionalized polyimide-based microporous films to prevent bacterial adhesion

Preventing microbial adhesion onto membranes is a crucial issue that determines the durability of the membrane. In this Research Article, we prepared aromatic polyimides (extensively employed for the elaboration of ultrafiltration membranes) containing PEO branches. Four polyimide-g-PEO copolymers were prepared from 6F dianhydride and a novel aromatic diamine containing PEO-550 side groups. The copolymers were designed to have variable PEO content, and were characterized by their spectroscopic and physical properties. The Breath Figure technique was successfully applied to create an ordered surface topography, where the PEO chains were preferentially located on the surface of the micrometer size holes. These unique features were explored to reduce bacterial adhesion. It was established that surface modified polyimide membranes have a high resistance to biofouling against Staphylococcus aureus. In particular, we observed that an increase of the PEO the content in the copolymer produced a decrease in the bacterial adhesion.

T-lymphocyte phenotype and function triggered by Aggregatibacter actinomycetemcomitans is serotype-dependent

BACKGROUND AND OBJECTIVE

Based on lipopolysaccharide (LPS) antigenicity, different Aggregatibacter actinomycetemcomitans serotypes have been described. Serotype b strains have demonstrated a stronger capacity to trigger cytokine production on dendritic cells (DCs). As DCs regulate the development of T-lymphocyte lineages, the objective of this investigation was to study the response of T lymphocytes after being stimulated with autologous DCs primed with different bacterial strains belonging to the most prevalent serotypes of A. actinomycetemcomitans in humans: a-c.

MATERIAL AND METHODS

Human DCs were primed with increasing multiplicity of infection (10(-1) -10(2) ) or the purified LPS (10-50 ng/mL) of A. actinomycetemcomitans serotypes a-c and then used to stimulate autologous naïve CD4(+) T lymphocytes. The T-helper (Th) type 1, Th2, Th17 and T-regulatory transcription factors T-bet, GATA-3, RORC2 and Foxp3, which are the master-switch genes implied in their specific differentiation, as well as T-cell phenotype-specific cytokine patterns were quantified by real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. In addition, the intracellular expression of T-bet/interferon-γ, GATA-3/interleukin-4, RORC2/interleukin-17A and Foxp3/transforming growth factor-β1 was analysed by double staining and flow cytometry.

RESULTS

All the A. actinomycetemcomitans serotypes led to T-lymphocyte activation; however, when T lymphocytes were stimulated with DCs primed with the A. actinomycetemcomitans serotype b strain or their purified LPS, higher levels of Th1- and Th17-associated transcription factors and cytokines were detected compared with similar experiments with the other serotypes.

CONCLUSION

These results demonstrate that serotype b of A. actinomycetemcomitans has a higher capacity of trigger Th1 and Th17 phenotype and function and it was demonstrated that their LPS is a more potent immunogen compared with the other serotypes.

First secondary case of Ebola outside Africa: epidemiological characteristics and contact monitoring, Spain, September to November 2014

On 6 October 2014, a case of Ebola virus disease (EVD) acquired outside Africa was detected in Madrid in a healthcare worker who had attended to a repatriated Spanish missionary and used proper personal protective equipment. The patient presented with fever <38.6 °C without other EVD-compatible symptoms in the days before diagnosis. No case of EVD was identified in the 232 contacts investigated. The experience has led to the modification of national protocols.

Modeling of coastal water contamination in Fortaleza (Northeastern Brazil)

An important tool in environmental management projects and studies due to the complexity of environmental systems, environmental modeling makes it possible to integrate many variables and processes, thereby providing a dynamic view of systems. In this study the bacteriological quality of the coastal waters of Fortaleza (a state capital in Northeastern Brazil) was modeled considering multiple contamination sources. Using the software SisBaHiA, the dispersion of thermotolerant coliforms and Escherichia coli from three sources of contamination (local rivers, storm drains and submarine outfall) was analyzed. The models took into account variations in bacterial decay due to solar radiation and other environmental factors. Fecal pollution discharged from rivers and storm drains is transported westward by coastal currents, contaminating strips of beach water to the left of each storm drain or river. Exception to this condition only occurs on beaches protected by the breakwater of the harbor, where counterclockwise vortexes reverse this behavior. The results of the models were consistent with field measurements taken during the dry and the rainy season. Our results show that the submarine outfall plume was over 2 km from the nearest beach. The storm drains and the Maceió stream are the main factors responsible for the poor water quality on the waterfront of Fortaleza. The depollution of these sources would generate considerable social, health and economic gains for the region.

Predominant role of GIP in the development of a metabolic syndrome-like phenotype in female Wistar rats submitted to forced catch-up growth

Catch-up growth has been associated with the appearance of metabolic dysfunctions such as obesity and type 2 diabetes in adulthood. Because the entero-insular axis is critical to glucose homeostasis control, we explored the relevance of the incretins glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) in the development of these pathologies. Offspring of rat dams fed ad libitum (control [C]) or 65% food-restricted during pregnancy and suckling time (undernourished [U]) were weaned onto a high-fat (HF) diet (CHF and UHF, respectively) to drive catch-up growth. Both male and female UHF rats showed an obese phenotype characterized by hyperphagy, visceral fat accumulation, and adipocyte hypertrophy. High-fat diet induced deterioration of glucose tolerance in a sex-dependent manner. Female UHF rats experienced much more severe glucose intolerance than males, which was not compensated by insulin hypersecretion, suggesting insulin resistance, as shown by homeostatic model assessment of insulin resistance values. Moreover, female, but not male, UHF rats displayed enhanced GIP but not GLP-1 secretion during oral glucose tolerance test. Administration of the GIP receptor antagonist (Pro3)GIP to UHF female rats over 21 days markedly reduced visceral fat mass and adipocyte hypertrophy without variations in food intake or body weight. These changes were accompanied by improvement of glucose tolerance and insulin sensitivity. In conclusion, the exacerbated production and secretion of GIP after the catch-up growth seems to represent the stimulus for insulin hypersecretion and insulin resistance, ultimately resulting in derangement of glucose homeostasis. Overall, these data evidence the role of GIP as a critical link between catch-up growth and the development of metabolic disturbances.

Inactivation of the pore-forming toxin Sticholysin I by peroxynitrite: protection by cys groups incorporated in the toxin

Sea anemones synthesize a variety of toxic peptides and proteins of biological interest. The Caribbean Sea anemone Stichodactyla helianthus, produces two pore-forming toxins, Sticholysin I (St I) and Stichloysin II (St II), with the ability to form oligomeric pores in cell and lipid bilayers characteristically lacking cysteine in their amino acid sequences. Recently, two mutants of a recombinant variant of Sticholysin I (rSt I) have been obtained with a Cys residue in functionally relevant regions for the pore-forming activity of the toxin: r St I F15C (in the amino terminal sequence) and r St I R52C (in the binding site). Aiming at characterizing the effects of oxidants in toxins devoid (r St I) or containing -SH moieties (r St I F15C and r St I R52C), we measured their hemolytic activity and pore forming capacity prior and after their incubation with peroxynitrite (ONOO(-)). At low ONOO(-)/Toxin ratios, nearly 0.8 Trp groups are modified by each added peroxynitrite molecule, and the toxin activity is reduced in ca. 20 %. On the other hand, in -SH bearing mutants only 0.5 Trp groups are modified by each peroxynitrite molecule and the toxin activity is only reduced in 10 %. The results indicated that Cys is the initial target of the oxidative damage and that Trp residues in Cys-containing toxins were less damaged than those in r St I. This relative protection of Trp groups correlates with a smaller loss of hemolytic activity and permeabilization ability in liposomes and emphasizes the relevance of Trp groups in the pore forming capacity of the toxins.

Ethanol production from glucose and xylose obtained from steam exploded water-extracted olive tree pruning using phosphoric acid as catalyst

In this work, the effect of phosphoric acid (1% w/w) in steam explosion pretreatment of water extracted olive tree pruning at 175°C and 195°C was evaluated. The objective is to produce ethanol from all sugars (mainly glucose and xylose) contained in the pretreated material. The water insoluble fraction obtained after pretreatment was used as substrate in a simultaneous saccharification and fermentation (SSF) process by a commercial strain of Saccharomyces cerevisiae. The liquid fraction, containing mainly xylose, was detoxified by alkali and ion-exchange resin and then fermented by the xylose fermenting yeast Scheffersomyces stipitis. Ethanol yields reached in a SSF process were close to 80% when using 15% (w/w) substrate consistency and about 70% of theoretical when using prehydrolysates detoxified by ion-exchange resins. Considering sugars recovery and ethanol yields about 160g of ethanol from kg of water extracted olive tree pruning could be obtained.

32 PREGNANCY OF EQUINE CLONED EMBRYOS MICROINJECTED WITH PLURIPOTENCY INDUCING GENES (Oct4, Sox2, c-Myc, K1f4)

Animal cloning is a high impact tool for scientific and economical production, but still with inefficient results. The efficiency of the cloning process depends on the state of differentiation of the donor cell. An adult equine somatic cell can be differentiated to a pluripotent stem cell (iPSC) inducing the expression of certain transcription factors (Oct4, Sox2, c-Myc, and K1f4; Breton et al. 2013). The objective of this work was to assess the effect of the intracytoplasmic injection of pluripotency inducing genes on embryo development and pregnancy rates of equine cloned embryos. Cumulus–oocyte complexes (COC) were obtained from slaughterhouse ovaries. Oocyte collection and maturation procedure were performed as described by Lagutina et al. (2007). After the removal of cumulus cells, oocytes showing first polar body were microinjected with a mixture 1/3 of plasmids/liposomes (Mi group). The plasmid used was the pEP4-E02s-EM2k, which encodes the human genes Oct4, Sox2, Myc, and K1f4. The DNA concentration was adjusted to 0.5 μg mL–1. Microinjected oocytes were enucleated using the zona free method. Adult male skin fibroblasts from the same animal were used as donor nucleus cells. These fibroblasts were attached to the ooplasts with phytohemagglutinin and then fused with an electric pulse. Activation was performed using 8.7 mM ionomycin for 4 min, followed by culture for 4 h in a combination of 1 mM 6-DMAP and 5 mg mL–1 cycloheximide. Zona free reconstructed embryos (ZFRE) were cultured for 7 to 8 days in DMEM-F12 in the well of the well (WOW) system, aggregating 3 embryos per well. A control group (CC group) of not microinjected embryos was included. Cleavage and blastocyst development was assessed at Days 2 and 7, respectively. Transcervical transfer of 49 Day 7 to 8 blastocysts was performed 6 days after ovulation. The mares received 2 blastocysts per transfer. Pregnancy was diagnosed by transrectal ultrasonography 15 days after ovulation. Cleavage and blastocyst rates were analysed by Chi-squared test and pregnancy rate by Fisher test (P < 0.05). Cleavage was 92.1% (n = 58/63) for the Mi group and 90.4% (n = 868/960) for the CC group. Blastocyst rate was statistically higher per well, 28.6% (n = 6/21) v. 13.4% (n = 43/320) but not per oocyte, 9.5% (n = 6/63) v. 4.5% (n = 43/960), for the Mi and CC groups, respectively. Pregnancy rate was 17% (n = 1/6) for the Mi group and 7% (n = 3/43) for the CC group. No twin pregnancies were found and all the pregnancies are still ongoing. The higher blastocyst rates obtained with the embryos microinjected with pluripotency inducing genes compared with the control group showed an improvement in embryo quality. In conclusion, the data presented indicate that the intracytoplasmic microinjection of pluripotency inducing genes in equine zona free cloned embryos improved blastocyst rates on a per well basis and showed a tendency to improve the pregnancy rates. The expression of the Oct4, Sox2, c-Myc, and K1f4 genes could be probably generating better reprogrammed donor nucleus compared with adult differentiated cells used in conventional cloning.

97 IN VIVO AND IN VITRO EMBRYO PRODUCTION WITH Y-SEXED SORTED OR CONVENTIONAL SEMEN IN BEEF CATTLE

An experiment was designed to evaluate in vivo and in vitro embryo production following the use of frozen–thawed conventional or Y-sexed semen from a Brangus bull with known high fertility. For in vivo embryo production, Brangus heifers (n = 12) were superovulated twice in a crossover design and inseminated with sexed or conventional semen. On Day 0, all heifers received an intravaginal progesterone device (DIB 1 g, Syntex S.A., Buenos Aires, Argentina) and 2.5 mg oestradiol benzoate and 50 mg progesterone (Progestar, Syntex S.A.) by intramuscular injection (IM). On Day 4, heifers were superstimulated with 200 mg of NIH-FSH-P1 Folltropin-V (Bioniche Animal Health, Belleville, Ontario, Canada) in twice-daily decreasing doses over 4 days. In the a.m. and p.m. of Day 6, all heifers received PGF2a (Ciclase, Syntex) and DIBs were removed in the p.m.. In the a.m. of Day 8, heifers received 100 μg de Gonadolerin (Gonasyn, Syntex S.A.) and were randomly allocated to receive either one straw of conventional semen (24 × 106 sperm per dose) 12 and 24 h later or two straws of sexed semen (2.4 × 106 sperm per dose) 18 and 24 h after GnRH. Ova/embryos were collected nonsurgically on Day 15 and evaluated following IETS recommendations. Means were compared by t-test. Mean ( ± s.e.m.) number of ova/embryos, fertilized ova, and transferable embryos were 14.8 ± 2.7, 9.4 ± 1.8, and 7.1 ± 1.7 v. 16.8 ± 3.1, 9.9 ± 2.5, and 8.1 ± 2.0 for donors inseminated with conventional or sexed semen, respectively (P > 0.6). For in vitro production, oocytes were obtained from 50 ultrasound-guided follicle aspiration (OPU) sessions that was performed at random stages of the oestrous cycle and without superstimulation in 22 Brangus cows and heifers. Oocytes were classified and matured in TCM-199 medium with NaHCO3 and supplemented with 1% fetal bovine serum. Semen samples from the same bull used for in vivo embryo production were selected using Percoll and capacitated in Fert medium and used at a final concentration of sperm/mL for nonsexed semen and 2 × 106 sperm mL–1 for sexed semen. After 16 h (sexed) or 18 h (conventional) in Fert medium, zygotes were denuded and cultured in SOF supplemented with 0.4% BSA under oil at 37°C, 5% CO2 and saturated humidity for 7 days. The total number of oocytes matured and fertilized was 528 and 318 for conventional and sexed semen, respectively. Means were compared by t-test and proportions by chi-squared test. Mean (± s.e.m.) number of cleaved zygotes and blastocysts produced per OPU session did not differ between conventional (11.0 ± 1.4 and 7.1 ± 1.0) and sexed (8.7 ± 0.8 and 4.9 ± 0.7; P > 0.2) semen. However, the proportion of cleaved zygotes and blastocysts produced were significantly higher (P < 0.05) with conventional semen (61.2%; 329/538 and 39.4%; 212/538) than with sexed semen (54.4%; 173/318 and 30.8%; 98/318), respectively. In conclusion, comparable number of embryos can be obtained in vivo with sexed or conventional semen from a bull with proven high fertility. However, the proportion of blastocysts produced in vitro is likely to be reduced following the use of sexed as compared with conventional semen from the same bull.

Reliability of retrospective assignment of gross motor function classification system scores

OBJECTIVES

To assess "alternate forms" reliability and inter-rater reliability of Gross Motor Function Classification System (GMFCS) scores.

METHODS

Fifty randomly selected children with cerebral palsy were divided into two groups: (1) GMFCS score assigned during gait assessment ("GMFCS previously assigned") and (2) no GMFCS score assigned. Using database information, two physiotherapists independently determined GMFCS scores for 25 children from the "previously assigned" group, and 25 from the "no score assigned" group. Therapists compared their recently assigned scores for the "previously assigned" group, discussing discrepancies until attaining agreement. This group's consensus scores were compared to GMFCS scores assigned at time of actual assessment to calculate "alternate forms" reliability.

RESULTS

Between-therapist agreements were kappa = 0.84 for "GMFCS previously assigned" group and 0.95 for "no GMFCS assigned" group. Kappa agreement between direct assessment and retrospectively assigned scores for the "GMFCS previously assigned" group was 0.79.

CONCLUSIONS

Retrospective GMFCS scores can be reliably assigned.

Undernutrition upregulates fumarate hydratase in the rat nucleus accumbens

Previous comparative studies of fumarate hydratase (FH) protein density revealed that the enzyme was overexpressed in the striatum of rodents that are less influenced by rewarding stimuli, from cocaine to food. Therefore, we recently proposed FH as a potential striatal biomarker of brain reward deficiency and addiction vulnerability. This work has been focused to investigate FH activity in the Nucleus Accumbens (NAc) of undernourished rats, taking into account that malnutrition has been related to increased responsiveness to food and drug reward. To this end, we have studied adult female Wistar rats severely food restricted from the 16th day of intrauterine life until adulthood. Animals were sacrificed to dissect the NAc and obtain mitochondrial and cytosolic fractions after homogenisation and centrifugation. FH activity was measured by conversion of malate to fumarate, and protein levels were compared by Western blot analysis when fractions showed differences in activity. Undernutrition did not change cytosolic FH activity but led to a marked increase of mitochondrial FH activity (72 %) and protein content (50 %) in the NAc. This change was in the opposite direction that one would predict if it was related to addiction vulnerability of some kind, but strongly suggests that mitochondrial FH needs to be at some optimal level for normal reward responsiveness.

53 EFFECT OF THE NUCLEAR REPROGRAMMING TIME ON IN VITRO DEVELOPMENT OF EQUINE AGGREGATED CLONED EMBRYOS

The time allowed for nuclear reprogramming is considered an essential factor for the efficiency of cloning and has not been evaluated in equine aggregated cloned embryos. The aim of our work was to assess the effect of different timing of activation stimulus after fusion of adult equine fibroblast cells to enucleated equine oocytes on embryo development and embryo quality. We processed a total of 1874 equine ovaries, recovering 3948 oocytes, of which 1914 (48.5%) had extruded the first polar body after 24 h of maturation. Oocyte collection, maturation, and the NT procedure were performed as described by Lagutina et al. (2007 Theriogenology 67, 90–98). Reconstructed oocytes (RO) were activated at 3 different times after cell fusion: (1) 1 h, (2) 1.5 h, and (3) 2 h. Activation was performed using 8.7 µM ionomycin for 4 min, followed by a 4-h culture in a combination of 1 mM DMAP and 5 mg mL–1 of cycloheximide. The RO were cultured in the well of the well system, aggregating 3 RO per well. The RO were cultured in DMEM-F12 with 5% fetal bovine serum (FBS) and antibiotics. Cleavage (48 h after activation), blastocyst, and expanded blastocyst rates (8–9 days) were assessed. In vitro development was compared using the chi-square test (P < 0.05). A total of 1608 RO were cultured. Cleavage was significantly lower in group 3 with respect to the other 2 groups [(1): 396/450, 88%; (2): 540/639, 84.5%; (3): 365/519, 70.3%]. There were no significant differences in blastocyst rates within the 3 groups considering the number of total RO [(1): 19/450, 4.2%; (2): 23/639, 3.6%; (3): 15/519, 2.9%] or aggregated RO per well [(1): 12.7%; (2): 10.8%; (3): 8.7%]. However, the rate of blastocyst expansion was higher (P < 0.05) in group 2 than in group 3 [(1): 17/19, 89.5%; (2): 23/23, 100%; (3): 11/15, 73.3%]. In conclusion, the timing of nuclear reprogramming did not affect blastocyst rates but affected cleavage rates and blastocyst quality. This indicates that 1 h before activation stimulus is enough for embryo development of equine aggregated cloned embryos.

Treatment with aliskiren/amlodipine combination in patients with moderate-to-severe hypertension: a randomised, double-blind, active comparator trial

AIMS

To assess the extent of reduction in blood pressure (BP) of aliskiren/amlodipine combination therapy compared with amlodipine monotherapy in moderate-to-severe hypertensive patients.

METHODS

This was an 8-week multicentre, randomised, double-blind study. After a 1-to 4-week washout period, eligible patients [mean sitting systolic blood pressure (msSBP) ≥ 160 to < 200 mmHg] were randomised to receive a once-daily dose of aliskiren/amlodipine 150/5mg (n = 244) or amlodipine 5 mg (n = 241) for 1 week, followed by up-titration to aliskiren/amlodipine 300/10 mg or amlodipine 10 mg for 7 weeks. Efficacy outcome measures included change from baseline to week 8 endpoint in msSBP (primary endpoint), mean sitting diastolic blood pressure (msDBP), and BP control rate (< 140/90 mmHg). Safety was assessed by monitoring and recording all adverse events (AEs) and laboratory abnormalities.

RESULTS

Patients' demographic characteristics were balanced between the two groups, mean baseline BP being 171.0/94.3 mmHg for aliskiren/amlodipine and 171.8/95.6 mmHg for amlodipine. Of 485 randomised patients, 433 (89.3%) completed the study. At week 8 endpoint, combination therapy resulted in significantly greater msSBP/msDBP reductions and BP control rate, compared with monotherapy (all: p ≤ 0.0001). The overall incidence of AEs was similar between the two groups. The most commonly reported AE was peripheral oedema with the incidence lower for combination therapy (14.4%) than for monotherapy (18.3%).

CONCLUSION

In this population with considerably elevated BP, use of aliskiren/amlodipine combination showed significantly greater BP reductions and allowed more patients to achieve BP control compared with amlodipine monotherapy, with no additional safety concerns.

Effectiveness of a diagnostic algorithm combining clinical probability, D-dimer testing, and computed tomography in patients with suspected pulmonary embolism in an emergency department

OBJECTIVE

The aim of our study was to assess the clinical effectiveness of a simplified algorithm using the Wells clinical decision rule, D-dimer testing, and computed tomography (CT) in patients with suspected pulmonary embolism (PE) in an Emergency Department (ED).

METHODS

Patients with clinically suspected PE from the Emergency Department were included from May 2007 through December 2008. Clinical probability was assessed using the Wells clinical decision rule and a VIDAS D-dimer assay was used to measure D-dimer concentration. Patients were categorized as "pulmonary embolism unlikely" or "pulmonary embolism likely" using the dichotomized version of the Wells clinical decision rule. Pulmonary embolism was considered excluded in patients with unlikely probability and normal D-dimer test (< 500 ng/ml). All other patients underwent CT, and pulmonary embolism was considered present or excluded based on the results. Anticoagulants were withheld from patients classified as excluded, and all patients were followed up for 3 months.

RESULTS

241 patients were included in the study. The prevalence of PE in the entire population was 23.6%. The combination of unlikely probability using the dichotomized Wells clinical decision rule and a normal D-dimer level occurred in 23.6%, thus making CT unnecessary. During the followup period, no thromboembolic events were recorded and there were no deaths related to venous thromboembolic disease (3-month thromboembolic risk 0% [95% CI, 0%-8%]).

CONCLUSIONS

In this study we have confirmed the effectiveness of a diagnostic management strategy using a simple clinical decision rule, D-dimer testing, and CT in the evaluation and management of patients with clinically suspected pulmonary embolism.

Studies of TBX4 and chromosome 17q23.1q23.2: an uncommon cause of nonsyndromic clubfoot

Clubfoot is a common birth defect characterized by inward posturing and rigid downward displacement of one or both feet. The etiology of syndromic forms of clubfoot is varied and the causes of isolated clubfoot are not well understood. A microduplication of 2.2 Mb on chromosome 17q23.1q23.2 which includes T-box 4 (TBX4), a hindlimb-specific gene, and 16 other genes was recently identified in 3 of 66 families reported as nonsyndromic clubfoot, but additional non-foot malformations place them in the syndromic clubfoot category. Our study assesses whether variation in or around TBX4 contributes to nonsyndromic clubfoot. To determine whether this microduplication was a common cause of nonsyndromic clubfoot, 605 probands (from 148 multiplex and 457 simplex families) with nonsyndromic clubfoot were evaluated by copy number and oligonucleotide array CGH testing modalities. Only one multiplex family (0.68%) that had 16 with clubfoot and 9 with other foot anomalies, had a 350 kb microduplication, which included the complete duplication of TBX4 and NACA2 and partial duplication of BRIP1. The microduplication was transmitted in an autosomal dominant pattern and all with the microduplication had a range of phenotypes from short wide feet and toes to bilateral clubfoot. Minimal evidence was found for an association between TBX4 and clubfoot and no pathogenic sequence variants were identified in the two known TBX4 hindlimb enhancer elements. Altogether, these results demonstrate that variation in and around the TBX4 gene and the 17q23.1q23.2 microduplication are not a frequent cause of this common orthopedic birth defect and narrows the 17q23.1q23.2 nonsyndromic clubfoot-associated region.