Phenotype-based high-content chemical library screening identifies statins as inhibitors of in vivo lymphangiogenesis.

Lymphangiogenesis plays an important role in promoting cancer metastasis to sentinel lymph nodes and beyond and also promotes organ transplant rejection. We used human lymphatic endothelial cells to establish a reliable three-dimensional lymphangiogenic sprouting assay with automated image acquisition and analysis for inhibitor screening. This high-content phenotype-based assay quantifies sprouts by automated fluorescence microscopy and newly developed analysis software. We identified signaling pathways involved in lymphangiogenic sprouting by screening the Library of Pharmacologically Active Compounds (LOPAC)(1280) collection of pharmacologically relevant compounds. Hit characterization revealed that mitogen-activated protein kinase kinase (MEK) 1/2 inhibitors substantially block lymphangiogenesis in vitro and in vivo. Importantly, the drug class of statins, for the first time, emerged as potent inhibitors of lymphangiogenic sprouting in vitro and of corneal and cutaneous lymphangiogenesis in vivo. This effect was mediated by inhibition of the 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase and subsequently the isoprenylation of Rac1. Supplementation with the enzymatic products of HMG-CoA reductase functionally rescued lymphangiogenic sprouting and the recruitment of Rac1 to the plasma membrane.

The functional outcome of forty-nine single-incision suture anchor repairs for distal biceps tendon ruptures at the elbow.

PURPOSE: The objective of this retrospective study was to evaluate the functional results of distal biceps tendon repair using suture anchors via a single-incision approach. METHODS: Forty-nine patients were re-examined at a mean follow-up of 44.2 ± 32.1 months (range, 12-119 months). Subjective and objective criteria included patient's satisfaction, active range of motion (ROM), maximum isometric strength in flexion (at 45° and 90°), and supination of both arms. Functional scoring included the Morrey elbow score (MES) and the QuickDASH. Furthermore, follow-up radiographs were performed. RESULTS: Eighty-six percent of patients were highly satisfied or satisfied with their outcome. Compared to contralateral, the active ROM of elbow flexion, extension, and pronation was not affected; however, supination was decreased by 3° (P < 0.001). The isometric maximum strengths showed significant deficits in all tested scenarios (at 45°, P = 0.002; at 90°, P < 0.001; for supination, P < 0.001). The MES and the QuickDASH were 97.2 ± 4.9 and 7.9 ± 13.9, respectively. Heterotopic ossifications (HO) were found in 39% of patients; however, with respect to scores and strength, no significant differences were seen compared to patients without HO. Moreover, four anchor failures were detected. CONCLUSIONS: Single-incision suture anchor repair provides high patient's satisfaction and good results with respect to ROM and functional scoring. Nevertheless, based on presented data, the patient has to be informed of postoperative HO and especially for supination strength weakness after surgery. Distal biceps tendon repair should be reserved for experienced upper extremity surgeons to avoid procedure-related complications.

Atypical Neural Plasticity and Behavioral Effects of Trustworthiness Learning in Borderline Personality Disorder Features.

This study distinguishes interpersonal trust learning with a novel trust learning paradigm in participants high (H-BPD) and low (L-BPD) in BPD features. Neutral faces were paired with trust-relevant behaviors in four conditions: trustworthy, untrustworthy, ambiguously trustworthy, and mixed trustworthiness. After training, participants rated faces on untrustworthiness as electroencephalographic measures were recorded. H-BPD rated neutral faces as significantly more untrustworthy than L-BPD at both time periods. Negative and ambiguous trustworthiness pairing conditions led to higher ratings of untrustworthiness, whereas trustworthy and mixed descriptors led to lower ratings of untrustworthiness. Learning enhanced the amplitude of an early sensory event-related potential (ERP) component (i.e., P1) for both groups. The slow-wave ERP, an index of sustained attention, revealed greater focus after learning to trustworthy descriptors in H-BPD and to untrustworthy descriptors in L-BPD. H-BPD utilized greater effort to overcome an inherent mistrust bias and L-BPD to overcome unexpected untrustworthy information.

A path forward for qualitative research on sustainability in the COVID-19 pandemic.

The unique strengths of qualitative research, through in-depth inquiry and identification of unexpected themes and linkages, is essential to our growing understanding of COVID-19's impacts on the social world and its intersection with sustainability science. However, many challenges-physical, psychological, and ethical in nature-face qualitative researchers during the pandemic, as social distancing and travel restrictions prevent in-person field work. In this paper, we outline the essential contributions of qualitative study to sustainability science, discuss current challenges, and in turn, provide recommendations for researchers.

Hyperaldosteronism in Klotho-deficient mice.

Klotho is a membrane protein participating in the inhibitory effect of FGF23 on the formation of 1,25-dihydroxyvitamin-D(3) [1,25(OH)(2)D(3)]. It participates in the regulation of renal tubular phosphate reabsorption and stimulates renal tubular Ca(2+) reabsorption. Klotho hypomorphic mice (klotho(hm)) suffer from severe growth deficit, rapid aging, and early death, events largely reversed by a vitamin D-deficient diet. The present study explored the role of Klotho deficiency in mineral and electrolyte metabolism. To this end, klotho(hm) mice and wild-type mice (klotho(+/+)) were subjected to a normal (D(+)) or vitamin D-deficient (D(-)) diet or to a vitamin D-deficient diet for 4 wk and then to a normal diet (D(-/+)). At the age of 8 wk, body weight was significantly lower in klotho(hm)D(+) mice than in klotho(+/+)D(+) mice, klotho(hm)D(-) mice, and klotho(hm)D(-/+) mice. Plasma concentrations of 1,25(OH)(2)D(3,) adrenocorticotropic hormone (ACTH), antidiuretic hormone (ADH), and aldosterone were significantly higher in klotho(hm)D(+) mice than in klotho(+/+)D(+) mice. Plasma volume was significantly smaller in klotho(hm)D(-/+) mice, and plasma urea, Ca(2+), phosphate and Na(+), but not K(+) concentrations were significantly higher in klotho(hm)D(+) mice than in klotho(+/+)D(+) mice. The differences were partially abrogated by a vitamin D-deficient diet. Moreover, the hyperaldosteronism was partially reversed by Ca(2+)-deficient diet. Ussing chamber experiments revealed a marked increase in amiloride-sensitive current across the colonic epithelium, pointing to enhanced epithelial sodium channel (ENaC) activity. A salt-deficient diet tended to decrease and a salt-rich diet significantly increased the life span of klotho(hm)D(+) mice. In conclusion, the present observation disclose that the excessive formation of 1,25(OH)(2)D(3) in Klotho-deficient mice results in extracellular volume depletion, which significantly contributes to the shortening of life span.

Accelerated suicidal erythrocyte death in Klotho-deficient mice.

Klotho, a membrane protein mainly expressed in parathyroid glands, kidney, and choroid plexus, counteracts aging and increases the life span. Accordingly, life span is significantly shorter in Klotho-deficient mice (klotho(-/-)) than in their wild-type littermates (klotho(+/+)). The pleotropic effects of Klotho include inhibition of 1,25-dihydroxyvitamin D(3)(1,25(OH)(2)D(3)) formation. Vitamin D-deficient diet reverses the shortening of life span in klotho(-/-) mice. In a variety of cells, 1,25(OH)(2)D(3) stimulates Ca(2+) entry. In erythrocytes, increased Ca(2+) entry stimulates suicidal erythrocyte death, which is characterized by cell shrinkage and phosphatidylserine exposure at the erythrocyte surface. The present study explored the putative impact of Klotho on eryptosis. According to Fluo3 fluorescence, cytosolic Ca(2+) concentration was significantly larger in klotho(-/-) erythrocytes as compared to klotho(+/+) erythrocytes. According to annexin V-binding, phosphatidylserine exposure was significantly enhanced, and according to forward scatter, cell volume significantly decreased in klotho(-/-) erythrocytes as compared to klotho(+/+) erythrocytes. Energy depletion (13 h glucose depletion) and oxidative stress (35 min 1 mM tert-butyl-hydroxyl-peroxide [tert-BOOH]) increased phosphatidylserine exposure to values again significantly larger in klotho(-/-) erythrocytes as compared to klotho(+/+) erythrocytes. Reticulocyte number was significantly increased in klotho (-/-) mice, pointing to enhanced erythrocyte turnover. Vitamin D-deficient diet reversed the enhanced Ca(2+) entry and annexin V-binding of klotho(-/-) erythrocytes. The present observations reveal a novel function of Klotho, i.e., the at least partially vitamin D-dependent regulation of cytosolic Ca(2+) activity in and suicidal death of erythrocytes.

Identification of SLC26A4 gene mutations in Iranian families with hereditary hearing impairment.

Mutations in the SLC26A4 gene at the DFNB4 locus are responsible for Pendred syndrome and non-syndromic hereditary hearing loss (DFNB4). This study included 80 nuclear families with two or more siblings segregating presumed autosomal recessive hearing loss. All deaf persons tested negative for mutations in GJB2 at the DFNB1 locus and were, therefore, screened for autozygosity by descent (ABD) using short tandem repeat polymorphisms (STRPs) that flanked SLC26A4. In 12 families, homozygosity for STRPs suggested possible ABD in this genomic region. Affected individuals in five families had a positive perchlorate discharge test. Sequence analysis of SLC26A4 identified ten mutations in eight families (T420I, 1197delT, G334V, R409H, T721M, R79X, S448L, L597S, 965insA and L445W), of which, four are novel (T420I, G334V, 965insA and R79X). These results imply that Pendred syndrome is the most prevalent form of syndromic hereditary hearing loss in Iran.

Dynamic contribution of nestin-expressing stem cells to adult neurogenesis.

Understanding the fate of adult-generated neurons and the mechanisms that influence them requires consistent labeling and tracking of large numbers of stem cells. We generated a nestin-CreER(T2)/R26R-yellow fluorescent protein (YFP) mouse to inducibly label nestin-expressing stem cells and their progeny in the adult subventricular zone (SVZ) and subgranular zone (SGZ). Several findings show that the estrogen ligand tamoxifen (TAM) specifically induced recombination in stem cells and their progeny in nestin-CreER(T2)/R26R-YFP mice: 97% of SGZ stem-like cells (GFAP/Sox2 with radial glial morphology) expressed YFP; YFP+ neurospheres could be generated in vitro after recombination in vivo, and maturing YFP+ progeny were increasingly evident in the olfactory bulb (OB) and dentate gyrus (DG) granule cell layer. Revealing an unexpected regional dissimilarity in adult neurogenesis, YFP+ cells accumulated up to 100 d after TAM in the OB, but in the SGZ, YFP+ cells reached a plateau 30 d after TAM. In addition, most SVZ and SGZ YFP+ cells became neurons, underscoring a link between nestin and neuronal fate. Finally, quantification of YFP+ cells in nestin-CreER(T2)/R26R-YFP mice allowed us to estimate, for example, that stem cells and their progeny contribute to no more than 1% of the adult DG granule cell layer. In addition to revealing the dynamic contribution of nestin-expressing stem cells to adult neurogenesis, this work highlights the utility of the nestin-CreER(T2)/R26R-YFP mouse for inducible gene ablation in stem cells and their progeny in vivo in the two major regions of adult neurogenesis.

SIX1 mutation screening in 247 branchio-oto-renal syndrome families: a recurrent missense mutation associated with BOR.

Branchio-oto-renal syndrome (BOR) is a clinically heterogeneous autosomal dominant form of syndromic hearing loss characterized by variable hearing impairment, malformations of the pinnae, the presence of branchial arch remnants, and various renal abnormalities. Both EYA1 and SIX1 are expressed in developing otic, branchial and renal tissue. Consistent with this expression pattern, mutations in both genes cause BOR syndrome. Mutations in EYA1 are found in approximately 40% of patients with the BOR phenotype, however, the role of SIX1 is much lower. To date only three different SIX1 mutations have been described in BOR patients. The current screen of 247 BOR families detected five novel SIX1 mutations (c.50T>A, c.218A>C, c.317T>G, c.329G>A, c.334C>T) and one previously reported mutation (c.328C>T) seen in 5 unrelated families. All mutations are within the protein-binding Six domain. Phenotypic variability was high in these BOR families. Seven of the eight known SIX1 mutations are missense and the one in frame deletion is predicted to be functionally similar. The wide phenotypic variability precludes making genotype-phenotype correlations at this time.

Branchio-oto-renal syndrome (BOR): novel mutations in the EYA1 gene, and a review of the mutational genetics of BOR.

Branchio-oto-renal syndrome (BOR) is an autosomal dominant disorder characterized by the association of branchial and external ear malformations, hearing loss, and renal anomalies. The phenotype varies from ear pits to profound hearing loss, branchial fistulae, and kidney agenesis. The most common gene mutated in BOR families is EYA1, a transcriptional activator. Over 80 different disease-causing mutations have been published (www.healthcare.uiowa.edu/labs/pendredandbor/, last accessed 20 November 2007). We analyzed the EYA1 coding region (16 exons) from 435 families (345 at the University of Iowa [UI] and 95 at Boys Town National Research Hospital [BTNRH], including five at both) and found 70 different EYA1 mutations in 89 families. Most of the mutations (56/70) were private. EYA1 mutations were found in 31% of families (76/248) fitting established clinical criteria for BOR and 7% of families with questionable BOR phenotype (13/187). Severity of the phenotype did not correlate with type of mutation nor with the domain involved. These results add considerably to the spectrum of EYA1 mutations associated with BOR and indicate that the BOR phenotype is an indication for molecular studies to diagnose EYA1-associated BOR.

Cisplatin and dimethyl sulfoxide react to form an adducted compound with reduced cytotoxicity and neurotoxicity.

PURPOSE: We present work that demonstrates that cisplatin reacts rapidly with dimethyl sulfoxide (DMSO) in solution and identify the structure and reactivity of the resulting compound. METHODS: Electrospray ionization-mass spectrometry (ESI-MS) and NMR were used to identify the chemical structure of compounds formed when DMSO reacts with cisplatin. We studied the reactivity of the identified compound with DNA. In vitro toxicity studies in neurons and cancer cells and in vivo toxicity studies in rats were used to determine both the cancer chemotherapeutic and toxic effects of the identified compound. RESULTS: Cisplatin binds rapidly with DMSO to form a DMSO adduct. The resulting compound has reduced ability to bind to double-stranded DNA both in vitro and in cells. This compound has reduced toxicity for cancer cells and neurons in vitro. In vivo nephrotoxicity studies show that the adducted compound has different nephrotoxicity and elimination characteristics than cisplatin. CONCLUSIONS: From this work, we conclude that dissolving cisplatin in DMSO results in formation of an adducted compound with different therapeutic and biological characteristics. Furthermore, future studies which propose using DMSO in combination with cisplatin for chemotherapeutic treatment in patients must be reconsidered. Due to the rapidity and nature of the reaction, DMSO and cisplatin should not be combined for patient treatment.

Social Cognition and Borderline Personality Disorder: Splitting and Trust Impairment Findings.

The Borderline personality disorder (BPD) diagnosis has its origins in the concept of borderline personality organization (BPO). BPO is rooted in psychoanalytic object relations theory (ORT) which conceptualizes BPD and BPO to exhibit a propensity to view significant others as either idealized or persecutory (splitting) and a trait-like paranoid view of interpersonal relations. From the ORT model, those with BPD think that they will ultimately be betrayed, abandoned, or neglected by significant others, despite periodic idealizations. This article synthesizes the extant literature splitting and trust impairments in BPD, identifies avenues for further investigation, and discusses the relative promise of different methods to evaluate these clinical processes.

Symmetry aortic connector devices and acute renal injury: a comparison of renal dysfunction after three different aortocoronary bypass surgery techniques.

Although the pathogenesis of acute renal injury after cardiac surgery is multifactorial, atherosclerosis of the ascending aorta and embolic burden are strong independent predictors. Use of the Symmetry aortic connector device (ACD) for proximal anastomosis of coronary grafts may reduce ascending aortic atheroembolism. Therefore, we tested the hypothesis that off-pump coronary artery bypass (OPCAB) surgery performed using an ACD is associated with less postoperative renal dysfunction compared with conventional OPCAB or on-pump coronary artery bypass graft (CABG) surgery. Three-thousand-three-hundred consecutive patients undergoing non-emergent aortocoronary bypass surgery were retrospectively divided into three groups by surgical procedure; Group A: OPCAB with ACD (n = 124), Group B: standard OPCAB (n = 313), Group C: on-pump CABG (n = 2863). Postoperative peak fractional change in creatinine compared with baseline was used as a measure of renal outcome. Multivariable analysis did not identify ACD use as an independent predictor of postoperative peak fractional change in creatinine (P = 0.71), although the relationships of several known renal risk factors with postoperative peak fractional change in creatinine were confirmed. We could not find evidence that OPCAB surgery using ACDs reduces acute renal injury compared with standard OPCAB or CABG surgery.

Stress-Induced Anxiety- and Depressive-Like Phenotype Associated with Transient Reduction in Neurogenesis in Adult Nestin-CreERT2/Diphtheria Toxin Fragment A Transgenic Mice.

Depression and anxiety involve hippocampal dysfunction, but the specific relationship between these mood disorders and adult hippocampal dentate gyrus neurogenesis remains unclear. In both humans with MDD and rodent models of depression, administration of antidepressants increases DG progenitor and granule cell number, yet rodents with induced ablation of DG neurogenesis typically do not demonstrate depressive- or anxiety-like behaviors. The conflicting data may be explained by the varied duration and degree to which adult neurogenesis is reduced in different rodent neurogenesis ablation models. In order to test this hypothesis we examined how a transient-rather than permanent-inducible reduction in neurogenesis would alter depressive- and anxiety-like behaviors. Transgenic Nestin-CreERT2/floxed diphtheria toxin fragment A (DTA) mice (Cre+DTA+) and littermates (Cre+DTA-; control) were given tamoxifen (TAM) to induce recombination and decrease nestin-expressing stem cells and their progeny. The decreased neurogenesis was transient: 12 days post-TAM Cre+DTA+ mice had fewer DG proliferating Ki67+ cells and fewer DCX+ neuroblasts/immature neurons relative to control, but 30 days post-TAM Cre+DTA+ mice had the same DCX+ cell number as control. This ability of DG neurogenesis to recover after partial ablation also correlated with changes in behavior. Relative to control, Cre+DTA+ mice tested between 12-30 days post-TAM displayed indices of a stress-induced anxiety phenotype-longer latency to consume highly palatable food in the unfamiliar cage in the novelty-induced hypophagia test, and a depression phenotype-longer time of immobility in the tail suspension test, but Cre+DTA+ mice tested after 30 days post-TAM did not. These findings suggest a functional association between adult neurogenesis and stress induced anxiety- and depressive-like behaviors, where induced reduction in DCX+ cells at the time of behavioral testing is coupled with stress-induced anxiety and a depressive phenotype, and recovery of DCX+ cell number corresponds to normalization of these behaviors.

A meta-analysis of the efficacy of preoperative surgical safety checklists to improve perioperative outcomes.

BACKGROUND: Meta-analyses of the implementation of a surgical safety checklist (SSC) in observational studies have shown a significant decrease in mortality and surgical complications. OBJECTIVE: To determine the efficacy of the SSC using data from randomised controlled trials (RCTs). METHODS: This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and was registered with PROSPERO (CRD42015017546). A comprehensive search of six databases was conducted using the OvidSP search engine. RESULTS: Four hundred and sixty-four citations revealed three eligible trials conducted in tertiary hospitals and a community hospital, with a total of 6 060 patients. All trials had allocation concealment bias and a lack of blinding of participants and personnel. A single trial that contributed 5 295 of the 6 060 patients to the meta-analysis had no detection, attrition or reporting biases. The SSC was associated with significantly decreased mortality (risk ratio (RR) 0.59, 95% confidence interval (CI) 0.42 - 0.85; p=0.0004; I2=0%) and surgical complications (RR 0.64, 95% CI 0.57 - 0.71; p<0.00001; I2=0%). The efficacy of the SSC on specific surgical complications was as follows: respiratory complications RR 0.59, 95% CI 0.21 - 1.70; p=0.33, cardiac complications RR 0.74, 95% CI 0.28 - 1.95; p=0.54, infectious complications RR 0.61, 95% CI 0.29 - 1.27; p=0.18, and perioperative bleeding RR 0.36, 95% CI 0.23 - 0.56; p<0.00001. CONCLUSIONS: There is sufficient RCT evidence to suggest that SSCs decrease hospital mortality and surgical outcomes in tertiary and community hospitals. However, randomised evidence of the efficacy of the SSC at rural hospital level is absent.

Multidimensional assessment of resilience in mothers who are child sexual abuse survivors.

OBJECTIVE: There has been relatively little attention given to positive adaptation following childhood sexual abuse (CSA), and typically such resilience has been explored primarily in the intrapersonal domain. This study explored questions about later resilience following CSA within a multidimensional framework by assessing resilience across intrapersonal, interpersonal, and intrafamilial domains. METHOD: This community sample consisted of 79 mothers with a history of CSA who had a child living at home with them. Participants completed four outcome measures (Center for Epidemiologic Studies--Depression Scale, Parenting Stress Index [PSI] Health Scale, PSI Parenting Competence Scale, and a measure of marital satisfaction). Risk and protective factors examined in relation to outcome included mother's age, socioeconomic status, severity of the CSA experience, coping strategy (avoidance, seeking social support, and problem solving), child characteristics, and spousal/partner support. RESULTS: Results indicated that when multiple adaptational domains were assessed, mothers showed discrepancies in how adequately they functioned across domains. While severity of the CSA experience was only weakly associated with outcome, use of avoidant coping emerged as a significant risk factor and was strongly and consistently associated with negative outcome across domains. Spousal/partner support was a strong protective factor and buffered the relationship between depressive symptoms and parenting competence. Difficult child characteristics were significantly associated with mothers' perceptions of physical health and parenting competence. CONCLUSIONS: The findings suggest the importance of comprehensive multimethod assessments of resilience and extend the knowledge of factors associated with positive outcome. The results highlight the need for further research exploring current contextual risk and protective factors associated with resilience in each domain.

GJB2: the spectrum of deafness-causing allele variants and their phenotype.

Genetic testing was completed on 1,294 persons with deafness referred to the Molecular Otolaryngology Research Laboratories to establish a diagnosis of DFNB1. Exon 2 of GJB2 was screened for coding sequence allele variants by denaturing high-performance liquid chromatography (DHPLC) complemented by bidirectional sequencing. If two deafness-causing mutations of GJB2 (encoding Connexin 26) were identified, further screening was not performed. If only a single deafness-causing mutation was identified, we screened for the g.1777179_2085947del (hereafter called del(GJB6-D13S1830); GenBank NT_024524.13) and mutations in the noncoding region of GJB2. Phenotype-genotype correlations were evaluated by categorizing mutations as either protein truncating or nontruncating. A total of 205 persons carried two GJB2 exon 2 mutations and were diagnosed as having DFNB1; 100 persons carried only a single deafness-causing allele variant of exon 2. A total of 37 of these persons were c.35delG carriers, and 51 carried other allele variants of GJB2. Persons diagnosed with DFNB1 segregating two truncating/nonsense mutations had a more severe phenotype than persons carrying two missense mutations, with mean hearing impairments being 88 and 37%, respectively (P < 0.05). The number of deaf c.35delG carriers was greater than expected when compared to the c.35delG carrier frequency in normal-hearing controls (P < 0.05), suggesting the existence of at least one other mutation outside the GJB2 coding region that does not complement GJB2 deafness-causing allele variants.

Gender and endogenous levels of estradiol do not influence adult hippocampal neurogenesis in mice.

In several species, including rat and vole, the proliferation of new neurons in the adult dentate gyrus (DG) subgranular zone (SGZ) is influenced by both gender and endogenous levels of the gonadotropic steroid hormone estradiol. However, little is known about how adult neurogenesis is regulated by these factors in the mouse. We report here that adult C57BL/6 mice do not have gender differences in hippocampal proliferation or neurogenesis. In addition, the production of new SGZ cells in female mice was not influenced by estrous cycle or after ovariectomy, suggesting that fluctuations in endogenous estradiol levels do not alter adult neurogenesis in the mouse. Both male and female mice had a greater number of BrdU-immunoreactive SGZ cells following chronic treatment with fluoxetine. This demonstrates a parallel proliferation response in both genders, and opens avenues for addressing the neurogenesis hypothesis of depression in female rodents. These findings underscore a distinct regulation of adult neurogenesis in mice vs. other rodents, and are discussed in regard to their implications for the study of adult hippocampal neurogenesis.

Branchio-oto-renal syndrome.

Branchio-oto-renal syndrome, a phenotype consisting of hearing loss, auricular malformations, branchial arch remnants, and renal anomalies is now recognized as one of the more common forms of autosomal dominant syndromic hearing impairment. Three loci known to be associated with the BOR phenotype have been identified and two genes that act in a regulatory network have been cloned, EYA1 and SIX1. EYA1 and SIX1 are homologous to genes involved in Drosophila eye development, eyes absent gene (eya), and sine oculis (so), respectively. EYA1, a transcriptional co-activator has a conserved, 271-amino acid, C-terminal known as the Eya Domain (ED). SIX1 has two highly conserved domains; a homeodomain (HD) and a specific Six-domain (SD) whose products function as transcription factors with specific DNA-binding activity that are crucial for protein-protein interaction. To determine the molecular basis for the organ defects that occur in BOR syndrome, many studies have focused on the effects of mutations to EYA and effects of mutations of the EYA-SIX regulatory system. However, over 60% of BOR syndrome patients do not have known mutations in EYA1 and relatively little is known about mutations to SIX1. Further evaluation of SIX1 and its related target genes may provide a better understanding of the pathophysiology of BOR syndrome and offer greater clues to the disease mechanisms.