Identification of an angiogenic factor that when mutated causes susceptibility to Klippel–Trenaunay syndrome

Genome-wide profile of pleural mesothelioma versus parietal and visceral pleura: the emerging gene portrait of the mesothelioma phenotype

BACKGROUND

Malignant pleural mesothelioma is considered an almost incurable tumour with increasing incidence worldwide. It usually develops in the parietal pleura, from mesothelial lining or submesothelial cells, subsequently invading the visceral pleura. Chromosomal and genomic aberrations of mesothelioma are diverse and heterogenous. Genome-wide profiling of mesothelioma versus parietal and visceral normal pleural tissue could thus reveal novel genes and pathways explaining its aggressive phenotype.

METHODOLOGY AND PRINCIPAL FINDINGS

Well-characterised tissue from five mesothelioma patients and normal parietal and visceral pleural samples from six non-cancer patients were profiled by Affymetrix oligoarray of 38 500 genes. The lists of differentially expressed genes tested for overrepresentation in KEGG PATHWAYS (Kyoto Encyclopedia of Genes and Genomes) and GO (gene ontology) terms revealed large differences of expression between visceral and parietal pleura, and both tissues differed from mesothelioma. Cell growth and intrinsic resistance in tumour versus parietal pleura was reflected in highly overexpressed cell cycle, mitosis, replication, DNA repair and anti-apoptosis genes. Several genes of the "salvage pathway" that recycle nucleobases were overexpressed, among them TYMS, encoding thymidylate synthase, the main target of the antifolate drug pemetrexed that is active in mesothelioma. Circadian rhythm genes were expressed in favour of tumour growth. The local invasive, non-metastatic phenotype of mesothelioma, could partly be due to overexpression of the known metastasis suppressors NME1 and NME2. Down-regulation of several tumour suppressor genes could contribute to mesothelioma progression. Genes involved in cell communication were down-regulated, indicating that mesothelioma may shield itself from the immune system. Similarly, in non-cancer parietal versus visceral pleura signal transduction, soluble transporter and adhesion genes were down-regulated. This could represent a genetical platform of the parietal pleura propensity to develop mesothelioma.

CONCLUSIONS

Genome-wide microarray approach using complex human tissue samples revealed novel expression patterns, reflecting some important features of mesothelioma biology that should be further explored.

Functional role of transcriptional factor TBX5 in pre-mRNA splicing and Holt-Oram syndrome via association with SC35

TBX5 is a T-box transcriptional factor required for cardiogenesis and limb development. TBX5 mutations cause Holt-Oram syndrome characterized by congenital heart defects and upper limb deformations. Here we establish a novel function for TBX5 in pre-mRNA splicing, and we show that this function is relevant to the pathogenesis of Holt-Oram syndrome, providing a novel pathogenic mechanism for the disease. Proteomics in combination with affinity purification identifies splicing factor SC35 as a candidate TBX5-associating protein. Co-immunoprecipitation and glutathione S-transferase pulldown assays confirm the complex formation between TBX5 and SC35. TBX5 can bind to RNA homopolymers (polyribonucleotides) and to the 5'-splice site, which overrides the binding of SC35 to the same RNA. Overexpression of TBX5 increases the efficiency of pre-mRNA splicing and regulates alternative splice site selection. However, co-expression of TBX5 and SC35 antagonizes each other's positive effect on splicing. The most severe TBX5 mutation, G80R, with complete penetrance of the cardiac phenotype, strongly affects pre-mRNA splicing, whereas other mutations with incomplete penetrance of the cardiac phenotype, including R237Q, do not alter the splicing activity of TBX5. This study establishes TBX5 as the first cardiac gene and the first human disease gene with dual roles in both transcriptional activation and pre-mRNA splicing.

Novel roles of GATA1 in regulation of angiogenic factor AGGF1 and endothelial cell function

AGGF1 is an angiogenic factor, and its deregulation is associated with a vascular malformation consistent with Klippel-Trenaunay syndrome (KTS). This study defines the molecular mechanism for transcriptional regulation of AGGF1 expression. Transcription of AGGF1 starts at two nearby sites, -367 and -364 bp upstream of the translation start site. Analyses of 5'- and 3'-serial promoter deletions defined the core promoter/regulatory elements, including two repressor sites (from -1971 to -3990 and from -7521 to -8391, respectively) and two activator sites (a GATA1 consensus binding site from -295 to -300 and a second activator site from -129 to -159). Both the GATA1 site and the second activator site are essential for AGGF1 expression. A similar expression profile was found for GATA1 and AGGF1 in cells (including various endothelial cells) and tissues. Electrophoretic mobility shift assay and chromatin immunoprecipitation assays demonstrated that GATA1 was able to bind to the AGGF1 DNA in vitro and in vivo. Overexpression of GATA1 increased expression of AGGF1. We identified one rare polymorphism -294C>T in a sporadic KTS patient, which is located in the GATA1 site, disrupts binding of GATA1 to DNA, and abolishes the GATA1 stimulatory effect on transcription of AGGF1. Knockdown of GATA1 expression by siRNA reduced expression of AGGF1, and resulted in endothelial cell apoptosis and inhibition of endothelial capillary vessel formation and cell migration, which was rescued by purified recombinant human AGGF1 protein. These results demonstrate that GATA1 regulates expression of AGGF1 and reveal a novel role for GATA1 in endothelial cell biology and angiogenesis.

Integrative analysis of genome-wide RNA interference screens

High-throughput genetic screens have exponentially increased the functional annotation of the genome over the past 10 years. Likewise, genome-scale efforts to map DNA methylation, chromatin state and occupancy, messenger RNA expression patterns, and disease-associated genetic polymorphisms, and proteome-wide efforts to map protein-protein interactions, have also created vast resources of data. An emerging trend involves combining multiple types of data, referred to as integrative screening. Examples include papers that report integrated data generated from large-scale RNA interference screens on the Wnt/beta-catenin pathway with either genotypic or proteomic data in colorectal cancer. These studies demonstrate the power of data integration to generate focused, validated data sets and to identify high-confidence candidate genes for follow-up experiments. We present the ongoing evolution and new strategies for the integrative screening approach with respect to understanding and treating human disease.

Genetics, epigenetics and pharmaco-(epi)genomics in angiogenesis

Angiogenesis is controlled by a balance between pro- and anti-angiogenic factors. Studies in mice and human beings have shown that this balance, as well as the general sensitivity of the endothelium to these factors, is genetically pre-determined. In an effort to dissect this genetic basis, different types of genetic variability have emerged: mutations and translocations in angiogenic factors have been linked to several vascular malformations and haemangiomas, whereas SNPs have been associated with complex genetic disorders, such as cancer, neurodegeneration and diabetes. In addition, copy number alterations of angiogenic factors have been reported in several tumours. More recently, epigenetic changes caused by aberrant DNA methylation or histone acetylation of anti-angiogenic molecules have been shown to determine angiogenesis as well. Initial studies also revealed a crucial role for microRNAs in stimulating or reducing angiogenesis. So far, most of these genetic studies have focused on tumour angiogenesis, but future research is expected to improve our understanding of how genetic variants determine angiogenesis in other diseases. Importantly, these genetic insights might also be of important clinical relevance for the use of anti-angiogenic strategies in cancer or macular degeneration.

Mutation in nuclear pore component NUP155 leads to atrial fibrillation and early sudden cardiac death

Atrial fibrillation (AF) is the most common form of sustained clinical arrhythmia. We previously mapped an AF locus to chromosome 5p13 in an AF family with sudden death in early childhood. Here we show that the specific AF gene underlying this linkage is NUP155, which encodes a member of the nucleoporins, the components of the nuclear pore complex (NPC). We have identified a homozygous mutation, R391H, in NUP155 that cosegregates with AF, affects nuclear localization of NUP155, and reduces nuclear envelope permeability. Homozygous NUP155(-/-) knockout mice die before E8.5, but heterozygous NUP155(+/-) mice show the AF phenotype. The R391H mutation and reduction of NUP155 are associated with inhibition of both export of Hsp70 mRNA and nuclear import of Hsp70 protein. These human and mouse studies indicate that loss of NUP155 function causes AF by altering mRNA and protein transport and link the NPC to cardiovascular disease.

New regulators of Wnt/beta-catenin signaling revealed by integrative molecular screening

The identification and characterization of previously unidentified signal transduction molecules has expanded our understanding of biological systems and facilitated the development of mechanism-based therapeutics. We present a highly validated small interfering RNA (siRNA) screen that functionally annotates the human genome for modulation of the Wnt/beta-catenin signal transduction pathway. Merging these functional data with an extensive Wnt/beta-catenin protein interaction network produces an integrated physical and functional map of the pathway. The power of this approach is illustrated by the positioning of siRNA screen hits into discrete physical complexes of proteins. Similarly, this approach allows one to filter discoveries made through protein-protein interaction screens for functional contribution to the phenotype of interest. Using this methodology, we characterized AGGF1 as a nuclear chromatin-associated protein that participates in beta-catenin-mediated transcription in human colon cancer cells.

Venous malformations: classification, development, diagnosis, and interventional radiologic management

Venous malformations are categorized as low-flow vascular malformations within the domain of vascular anomalies and are the most common vascular malformation encountered clinically. Venous malformations are by definition present at birth, undergo pari passu growth, and present clinically because of symptoms related to mass effect or stasis. Although diagnosis can usually be made by clinical history and examination, differentiation from other vascular and nonvascular entities often requires an imaging work-up that includes ultrasound, CT, MR imaging, and diagnostic phlebography. All decisions regarding imaging work-up and decision to treat must be coordinated though referral and discussions with a multidisciplinary team and be based on clearly defined clinical indications. Percutaneous image-guided sclerotherapy has become the mainstay of treatment for venous malformations and involves the introduction of any one of a number of endothelial-cidal sclerosants into the vascular spaces of the lesion, with each sclerosant possessing its own unique spectrum of advantages and disadvantages.

Diagnosis and management of lymphatic vascular disease

The lymphatic vasculature is comprised of a network of vessels that is essential both to fluid homeostasis and to the mediation of regional immune responses. In health, the lymphatic vasculature possesses the requisite transport capacity to accommodate the fluid load placed upon it. The most readily recognizable attribute of lymphatic vascular incompetence is the presence of the characteristic swelling of tissues, called lymphedema, which arises as a consequence of insufficient lymph transport. The diagnosis of lymphatic vascular disease relies heavily upon the physical examination. If the diagnosis remains in question, the presence of lymphatic vascular insufficiency can be ascertained through imaging, including indirect radionuclide lymphoscintigraphy. Beyond lymphoscintigraphy, clinically-relevant imaging modalities include magnetic resonance imaging and computerized axial tomography. The state-of-the-art therapeutic approach to lymphatic edema relies upon physiotherapeutic techniques. Complex decongestive physiotherapy is an empirically-derived, effective, multicomponent technique designed to reduce limb volume and maintain the health of the skin and supporting structures. The application of pharmacological therapies has been notably absent from the management strategies for lymphatic vascular insufficiency states. In general, drug-based approaches have been controversial at best. Surgical approaches to improve lymphatic flow through vascular reanastomosis have been, in large part, unsuccessful, but controlled liposuction affords lasting benefit in selected patients. In the future, specifically engineered molecular therapeutics may be designed to facilitate the controlled regrowth of damaged, dysfunctional, or obliterated lymphatic vasculature in order to circumvent or mitigate the vascular insufficiency that leads to edema and tissue destruction.

Genetic disorders associated with macrocephaly

Macrocephaly is associated with many genetic disorders and is a frequent cause of referral to the clinical geneticist. In this review we classify the commonly encountered macrocephaly disorders into useful categories and summarize recent genetic advances. Conditions where macrocephaly is a predominant aspect of the clinical presentation are discussed and a diagnostic approach to the common macrocephaly disorders is provided. Some emphasis is placed on familial macrocephaly (sometimes referred to as benign external hydrocephalus) and on the macrocephaly associated with autism spectrum disorders. The more recent conditions associated with the leukodystrophies and the organic acidurias are reviewed, but the well known conditions involving storage disorders and bone dysplasias are mentioned but not discussed. The genetic macrocephaly conditions cover a broad spectrum of gene disorders and their related proteins have diverse biological functions. As of yet it is not clear what precise biological pathways lead to generalized brain overgrowth.

The clinical spectrum of lymphatic disease

Lymphatic disease is quite prevalent, and often not well clinically characterized. Beyond lymphedema, there is a broad array of human disease that directly or indirectly alters lymphatic structure and function. The symptomatic and objective presentation of these patients can be quite diverse. In this review, we have attempted to provide a systematic overview of the subjective and objective spectrum of lymphatic disease, with consideration of all of the categories of disease that primarily or secondarily impair the functional integrity of the lymphatic system. Lymphedema is discussed, along with chromosomal disorders, lymphangioma, infectious diseases, lymphangioleiomyomatosis, lipedema, heritable genetic disorders, complex vascular malformations, protein-losing enteropathy, and intestinal lymphangiectasia.

Identification of association of common AGGF1 variants with susceptibility for Klippel-Trenaunay syndrome using the structure association program

Klippel-Trenaunay syndrome (KTS) is a severe congenital disorder characterized by capillary malformations, venous malformations or varicose veins, and hypertrophy of the affected tissues. The angiogenic factor gene AGGF1 was previously identified as a candidate susceptibility gene for KTS, but further genetic studies are needed to firmly establish the genetic relationship between AGGF1 and KTS. We analyzed HapMap data and identified two tagSNPs, rs13155212 and rs7704267 that capture information for all common variants in AGGF1. The two SNPs were genotyped in 173 Caucasian KTS patients and 477 Caucasian non-KTS controls, and both significantly associated with susceptibility for KTS (P= 0.004 and 0.013, respectively). Permutation testing also showed a significant empirical P value for the association (empirical P= 0.006 and 0.015, respectively). To control for potential confounding due to population stratification, the population structure for both cases and controls was characterized by genotyping of 38 ancestry-informative markers (AIMs) and the STRUCTURE program. The association between the AGGF1 SNPs and KTS remained significant after multivariate analysis by incorporating the inferred cluster scores as a covariate or after removal of outlier individuals identified by STRUCTURE. These results suggest that common AGGF1 variants confer risk of KTS.

[Sturge--Weber-Klippel--Trenaunay syndrome (case report)]

INTRODUCTION

Sturge-Weber syndrome is characterized by capillary malformations in the face, associated with leptomeningeal and choroidal venous malformations. Klippel-Trenaunay syndrome consists of the triad: capillary malformation of one leg, ipsilateral hypertrophy and varicose veins.

OBSERVATION

We report the case of a 23-year-old male patient who presented a complex congenital neurocutaneous syndrome with vascular malformations involving the brain, face and limbs and associated with epilepsia and leptomeningeal calcifications. The patient fulfilled the diagnostic criteria of both vascular phacomatosis syndromes.

DISCUSSION AND CONCLUSION

Similar descriptions of dual or overlapping syndromes have been published. Many show that there is no clear distinction between Klippel-Trenaunay syndrome and Sturge-Weber syndrome. There is a clinical and biological overlap. The complexity of the disease phenotypes shows that a classification based on an eponymous category does not enable resolution of the nosological problems. Some authors suggest that these vascular malformations are best described in anatomical/histological or functional terms. We report a new observation that illustrates these difficulties.

Macromelia masquerading as an acromegaloid syndrome in an adult with Klippel-Trénaunay syndrome

OBJECTIVE

To describe a case of Klippel-Trénaunay syndrome in an adult patient with symmetric macromelia suggestive of an acromegaloid syndrome.

METHODS

We report clinical and laboratory data that were extracted from the medical records of the study patient. We also survey the relevant reports identified through a MEDLINE search of the English-language literature published between January 1, 1996, and June 2, 2007, using the phrase, Klippel-Trénaunay syndrome.

RESULTS

A 28-year-old man was admitted to the hospital for weeping lymphedema of the left lower extremity. He had pronounced symmetric hypertrophy of all distal extremities, port-wine stains on his right neck, and varicosities on his left groin. The patient's insulinlike growth factor 1 concentration was 92 ng/mL (reference range, 117-329 ng/mL), which did not support the diagnosis of acromegaly. Klippel-Trénaunay syndrome is a rare congenital condition that belongs to a family of disorders characterized by tissue overgrowth. Classically, the syndrome presents as a triad of vascular malformations, cutaneous hemangiomas, and bone or soft-tissue hypertrophy usually affecting one extremity. The tissue hypertrophy in this syndrome is typically localized and asymmetric.

CONCLUSION

The recognition that the tissue hypertrophy in Klippel-Trénaunay syndrome can occur symmetrically will help avoid unnecessary and extensive workup for acromegaly.

An unusual case of Klippel-Trénaunay-Weber syndrome presenting with portosystemic encephalopathy

We report a unique male patient presenting with portosystemic encephalopathy (PSE) due to intrahepatic portohepatic venous (PHV) shunts. He was diagnosed as having Klippel-Trénaunay-Weber syndrome (KTWS) based on the findings of a hemitruncal port-wine stain with subcutaneous arteriovenous fistulae and varicose veins in the legs. However, limb-hypertrophy, which is one of the most cardinal manifestations of KTWS, was absent, and in KTWS, PSE is quite a rare clinical manifestation. Hence, the clinical picture of this patient was unusual. Our clinical observation suggests that KTWS can be one of the underlying disorders causing PSE.

Characterization of a familial t(16;22) balanced translocation associated with congenital cataract leads to identification of a novel gene, TMEM114, expressed in the lens and disrupted by the translocation

Molecular characterization of chromosomal rearrangements is a powerful resource in identification of genes associated with monogenic disorders. We describe the molecular characterization of a balanced familial chromosomal translocation, t(16;22)(p13.3;q11.2), segregating with congenital lamellar cataract. This led to the discovery of a cluster of lens-derived expressed sequence tags (ESTs) close to the 16p13.3 breakpoint. This region harbors a locus associated with cataract and microphthalmia. Long-range PCR and 16p13.3 breakpoint sequencing identified genomic sequence in a human genome sequence gap, and allowed identification of a novel four-exon gene, designated TMEM114, which encodes a predicted protein of 223 amino acids. The breakpoint lies in the promoter region of TMEM114 and separates the gene from predicted eye-specific upstream transcription factor binding sites. There is sequence conservation among orthologs down to zebrafish. The protein is predicted to contain four transmembrane domains with homology to the lens intrinsic membrane protein, LIM2 (also known as MP20), in the PMP-22/EMP/MP20 family. TMEM114 mutation screening in 130 congenital cataract patients revealed missense mutations leading to the exchange of highly-conserved amino acids in the first extracellular domain of the protein (p.I35T, p.F106L) in two separate patients and their reportedly healthy sibling and mother, respectively. In the lens, Tmem114 shows expression in the lens epithelial cells extending into the transitional zone where early fiber differentiation occurs. Our findings implicate dysregulation of expression of this novel human gene, TMEM114, in mammalian cataract formation.

Prenatal sonographic findings of Klippel-Trénaunay-Weber syndrome

We describe the prenatal sonographic findings in a case of Klippel-Trénaunay-Weber syndrome including fetal ascites and subcutaneous cystic lesions associated with a relatively low level of maternal serum alpha-fetoprotein and a relatively high level of maternal serum beta-human chorionic gonadotrophin. Klippel-Trénaunay-Weber syndrome may present prenatally with fetal ascites and an abnormal maternal serum screening result in addition to fetal limb hypertrophy and subcutaneous cystic lesions.

Urogenital involvement in the Klippel-Trenaunay-Weber syndrome. Treatment options and results

OBJECTIVE

Klippel-Trenaunay-Weber syndrome (KTWS) is a congenital condition characterized by vascular malformations of the capillary, venous and lymphatic systems associated to soft tissue and bone hypertrophy in the affected areas. This syndrome may involve bladder, kidney, urethra, ureter and genitals. We report the treatment of 7 KTWS patients with urogenital involvement.

MATERIALS AND METHODS

From 1995 to 2005, 7 patients with KTWS were evaluated and the charts of these patients were reviewed.

RESULTS

Patients' median age was 19-years (range 4 to 46-years) and only 1 was female. The clinical presentation included genital deformities in 3 cases, hematuria in 2 and urethrorragia in 2, one of which associated with cryptorchidism and phimosis. Three patients had an association of pelvic and genital malformations, including 2 patients with hematuria due to vesical lesions and 1 patient with left ureterohydronephrosis due to a pelvic mass. Two patients had urethral lesions. Treatment included endoscopic laser coagulation for 1 patient with recurrent hematuria and 1 patient with urethrorrhagia, pelvic radiotherapy for 1 patient with hematuria and circumcision in 2 patients with genital deformities. One patient required placement of a double-J catheter to relieve obstruction. Hematuria and urethrorragia were safely and effectively controlled with laser applications. Circumcision was also effective. The patient treated with radiotherapy developed a contracted bladder and required a continent urinary diversion.

CONCLUSIONS

Urogenital involvement in patients with KTWS is not rare and must be suspected in the presence of hematuria or significant cutaneous deformity of the external genitalia. Surgical treatment may be warranted in selected cases.

Parkes Weber syndrome occurring in a family with capillary malformations

Parkes Weber syndrome is a disorder characterized by cutaneous blush, arteriovenous fistula, and overgrowth of the affected limb. It has been differentiated from Klippel-Trenaunay syndrome on the basis of the presence of arteriovenous fistula that are always absent in the latter. We report a case of Parkes Weber syndrome with diffuse arteriovenous high flow leading to hemodynamic complications but without radiographic evidence of arteriovenous fistula. There are multiple individuals in the family with capillary malformations inherited in an autosomal dominant pattern. These observations reinforce the suggestions that Parkes Weber syndrome and capillary malformations may share a common pathogenetic pathway.

Vascular malformations. Part II: associated syndromes

Cutaneous vascular malformations are rare disorders representing errors in vascular development. These lesions occur much less commonly but are often confused with the common infantile hemangioma. It is important to properly diagnose vascular malformations because of their distinct differences in morbidity, prognosis and treatment. Vascular malformations may be associated with underlying disease or systemic anomalies. Several of these syndromes are well defined and can often be distinguished on the basis of the flow characteristics of the associated vascular malformation.

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be able to better recognize underlying diseases or systemic anomalies that may be associated with vascular malformations. Participants should also better understand the various syndromes and conditions discussed and become more familiar with their management.

Cardiac-specific overexpression of SCN5A gene leads to shorter P wave duration and PR interval in transgenic mice

The Cardiac sodium channel gene SCN5A plays a critical role in cardiac electrophysiology and its mutations, either gain- or loss-of-functions, are associated with lethal arrhythmias. In this study, we investigated the effect of overexpression of SCN5A on the cardiac phenotype in a transgenic mouse model (TG-WT L10). Compared to NTG mice, heart rate, QRS duration, and QT intervals remained unchanged in TG-WT mice. Moreover, no spontaneous ventricular arrhythmias were detected in TG-WT hearts. Despite these results, a mild, irregular cardiac phenotype was observed in TG-WT mice. The P wave and PR interval were significantly shorter in TG-WT compared with NTG mice (P, 8.8+/-0.8 ms vs. 12.6+/-0.9 ms; PR, 12.5+/-2 ms vs. 33.5+/-0.7 ms). Furthermore, spontaneous premature atrial contractions were often detected in TG-WT mice. These results suggest that the expression level of the SCN5A gene is a determinant for the length of the P wave duration and PR interval on electrocardiograms (ECG).

Hemodynamic impairment, venous segmental disease, and clinical severity scoring in limbs with Klippel-Trenaunay syndrome

BACKGROUND

Klippel-Trenaunay syndrome (KTS) is a complex congenital anomaly featuring two or more of the following: (1) capillary malformations (port-wine stains), (2) soft tissue or bony hypertrophy (or both), and (3) varicose veins or venous malformations. With the purpose of determining the actual significance of venous impairment in patients with KTS, we quantified the venous valvular competency and calf muscle pump function and examined their effect on clinical severity.

METHODS

Included were patients with near-normal function of affected limb(s) and minimal/small foot hypertrophy. Excluded were those with deep venous hypoplasia, aplasia or thrombosis, lymphedema, limb length discrepancy (>2.5 cm), peripheral arterial (ankle-brachial index <1.0), or cardiac disease and walking impairment. Venous duplex scanning, ascending venography, magnetic resonance imaging, strain gauge plethysmography, and a bone scanogram were performed. We studied eight men and seven women aged 15 to 51 years (median, 24 years). The KTS involved 17 limbs (unilateral in 13 patients and bilateral in 2). Contralateral limbs in patients with unilateral KTS acted as controls (n = 13). Venous clinical severity was graded according to the CEAP and venous clinical severity score (VCSS), and reflux complexity was classified according to the venous segmental disease score. Outflow obstruction (outflow fraction at 1 and 4 seconds; OF(1) and OF(4), respectively), reflux (venous filling index), calf muscle pump function (ejection fraction), and hypertension (residual volume fraction) were determined in both limbs with strain gauge plethysmography. Data, reported as median and interquartile range, were analyzed with the Mann-Whitney test.

RESULTS

Varicose veins or venous malformations occurred in the medial, posterior, or anterolateral limb segments of the ankle (7/17, 7/17, and 9/17), calf (10/17, 8/17, and 12/17), knee (9/17, 8/17, and 8/17), and thigh (10/17, 6/17, and 8/17, respectively). Venous malformations occupied the subcutaneous space (17/17) and extended into the subfascial space in 6 (35.3%) of 17 limbs. Abnormal reflux (>0.5 seconds) was distributed in the great (64.7%; 11/17) and small (5.9%; 1/17) saphenous veins and the common femoral (23.5%; 4/17), femoral (41.1%; 7/17), popliteal (29.4%; 5/17), perforator (70.6%; 12/17), and axial calf (35.3%; 6/17) veins. There was no difference in the OF(1) and OF(4) between the affected limbs and the controls. Limbs with KTS had a fivefold greater venous filling index (0.133-0.46 mL . 100 mL(-1) . s(-1); 0.258 mL . 100 mL(-1) . s(-1)) than the controls (0.034-0.055 mL . 100 mL(-1) . s(-1); 0.046 mL . 100 mL(-1) . s(-1); P < .0001), and this was linked to a higher venous segmental disease score (3 [2-4] vs 0 [0-1]; P < .0001). Limbs with KTS had half the ejection fraction (20.8%; 12.3%-24%) of the controls (39.3%; 30.9%-64.6%) and twice as high a residual venous fraction (77% [69.6%-84.5%] vs 40.9% [20.6%-60%]; both P < .004). Patients complained of swelling (100%; 15/15), aching (100%; 15/15), pain (93.3%; 14/15) and heaviness (100%; 15/15), tiredness (66.7%; 10/15), and tightness (33.3%; 5/15) of the limb(s) with KTS. Limbs with KTS had a worse (1) venous clinical severity by 11 VCSS points (11 [8-12] vs 0 [0-1]) and (2) clinical status by 3 CEAP classes (C3 [C3-C4] vs C0 [C0-C2]) than the control limbs (both P < .0001).

CONCLUSIONS

Venous disease in limbs with KTS is a major source of morbidity in affected patients. Limbs with KTS are characterized by complex reflux patterns, severe valvular incompetence, calf muscle pump impairment, and venous hypertension, thus explaining the advanced clinical severity (VCSS) and CEAP grade.

Klippel-Trenaunay syndrome: a multisystem disorder possibly resulting from a pathogenic gene for vascular and tissue overgrowth

Klippel-Trenaunay syndrome is characterized by a triad of varicose veins, cutaneous capillary malformation, and hypertrophy of bone and soft tissue. Appropriate evaluation and treatment of children displaying features of the disease may minimize morbidity. The clinical appearance, etiology, genetics, diagnostics, and treatment of Klippel-Trenaunay syndrome are herein explored.

New techniques for the evaluation and therapeutic planning of patients with Klippel-Trénaunay syndrome

BACKGROUND

Klippel-Trénaunay syndrome (KTS) is a well-known eponym for a capillary-lymphatic-venous malformation which is associated with soft tissue and skeletal hypertrophy, usually of one or more limbs. Plain films, sonograms, conventional venograms, and arteriograms have been employed for the evaluation of the disease.

OBJECTIVE

To demonstrate the usefulness of multidetector computed tomography (MDCT) and fast 3-dimensional magnetic resonance imaging (3D-MR) venography for the assessment and therapeutic planning of patients with KTS.

METHODS

A prospective study in 16 consecutive patients with KTS using MDCT and 3D-MR venography, performed between January 2004 and January 2006 in a university hospital in Pamplona, Spain.

RESULTS

In nearly all patients, persistent embryologic veins were observed, and in one subject aplasia/atresia of the whole deep venous system of the affected extremity was seen. In four individuals hypoplasia of the femoral vein was observed; one subject had duplication of the femoral vein, and in three patients aplasia/atresia of this vein was found. Only half of the patients had normal popliteal veins. In one patient, aneurysmal dilatation of the popliteal vein was detected, and in six subjects, aplasia of this vein was observed. The presence of geographic stains was suggestive of hypoplasia and/or aplasia of femoral and popliteal veins.

LIMITATIONS

The small size of the group of patients with KTS, which is related to low incidence of the disease.

CONCLUSIONS

MDCT and 3D-MR venography are extremely helpful for the global evaluation of patients with KTS. Information regarding soft tissue and bony anatomy as well as information about superficial and deep venous systems may be obtained with a single exam.

Principles and therapeutic implications of angiogenesis, vasculogenesis and arteriogenesis

The vasculature is the first organ to arise during development. Blood vessels run through virtually every organ in the body (except the avascular cornea and the cartilage), assuring metabolic homeostasis by supplying oxygen and nutrients and removing waste products. Not surprisingly therefore, vessels are critical for organ growth in the embryo and for repair of wounded tissue in the adult. Notably, however, an imbalance in angiogenesis (the growth of blood vessels) contributes to the pathogenesis of numerous malignant, inflammatory, ischaemic, infectious and immune disorders. During the last two decades, an explosive interest in angiogenesis research has generated the necessary insights to develop the first clinically approved anti-angiogenic agents for cancer and blindness. This novel treatment is likely to change the face of medicine in the next decade, as over 500 million people worldwide are estimated to benefit from pro- or anti-angiogenesis treatment. In this following chapter, we discuss general key angiogenic mechanisms in health and disease, and highlight recent developments and perspectives of anti-angiogenic therapeutic strategies.

Gene prioritization through genomic data fusion

The identification of genes involved in health and disease remains a challenge. We describe a bioinformatics approach, together with a freely accessible, interactive and flexible software termed Endeavour, to prioritize candidate genes underlying biological processes or diseases, based on their similarity to known genes involved in these phenomena. Unlike previous approaches, ours generates distinct prioritizations for multiple heterogeneous data sources, which are then integrated, or fused, into a global ranking using order statistics. In addition, it offers the flexibility of including additional data sources. Validation of our approach revealed it was able to efficiently prioritize 627 genes in disease data sets and 76 genes in biological pathway sets, identify candidates of 16 mono- or polygenic diseases, and discover regulatory genes of myeloid differentiation. Furthermore, the approach identified a novel gene involved in craniofacial development from a 2-Mb chromosomal region, deleted in some patients with DiGeorge-like birth defects. The approach described here offers an alternative integrative method for gene discovery.

Klippel-Trenaunay-Weber syndrome and intramedullary cervical cavernoma: a very rare association. Case report

BACKGROUND

Klippel-Trenaunay-Weber syndrome is a rare mesodermal phakomatosis characterized by cutaneous hemangiomata, venous varicosities, and osseous-soft tissue hypertrophy of the affected limb. As the pathologic aspect of KTWS arises from the site in which malformations occur, the clinical picture varies widely from patients who complain for cosmetic reasons to patients with life-threatening lesions.

CASE DESCRIPTION

We describe a very rare case in which KTWS was associated with a cervical intramedullary cavernous angioma surgically treated.

CONCLUSION

This report confirms the wide range of expression of vascular abnormalities in neurocutaneous developmental diseases and the need of a careful multisystemic evaluation of these patients.

Management of Hemangiomas and Pediatric Vascular Malformations

Pediatric vascular anomalies can be difficult to diagnose and complex to treat. One must be able to distinguish hemangiomas from various vascular malformations, as well as appreciate their dynamic course with time. Thorough understandings of the clinical and diagnostic techniques used to evaluate these lesions are paramount for the treating surgeon. In addition, knowledge of current treatments from watchful waiting to radical extirpation is mandatory. This must all be done in the setting of a developing child. We present a current review of the literature regarding the comprehensive care of pediatric vascular lesions.

Klippel Trenauney syndrome and reduction mammoplasty

Klippel Trenauney syndrome is a rare congenital abnormality that includes extremity hypertrophy. We report an unusual case of breast asymmetry due to unilateral chest and limb hypertrophy and describe successful unilateral breast reduction. We highlight the potential problems of surgery within this group and a management approach to minimise complications.

Angiogenesis

Angiogenesis inhibitors for the treatment of cancer have now been approved by the Food and Drug Administration in the United States, and in 28 other countries including China. Clinical application of this new class of drugs is informed by certain principles from angiogenesis research. Oncogenic mutations initiate tumorigenesis, but angiogenesis is necessary for expansion of tumor mass. Two angiogenesis inhibitors have been developed that have a broad spectrum of anticancer activity, yet virtually no side effects. Endogenous angiogenesis inhibitors act as tumor suppressor proteins. The angiogenic response in vivo is based on the genetic background of the host. Several types of angiogenesis inhibitors reveal a biphasic, U-shaped curve of efficacy. "Antiangiogenic chemotherapy" is a novel approach to the treatment of drug resistance.

Update on the molecular genetics of vascular anomalies

Genetic factors play a critical role in the pathogenesis of vascular anomalies. Significant advances have been made in recent years in identifying the genetic and molecular determinants of a variety of vascular anomalies using a molecular genetic approach. Several genes for vascular anomalies have been identified. These genes include AGGF1 for Klippel-Trenaunay syndrome, RASA1 for capillary malformations, KRIT1, MGC4607, PDCD10 for cerebral cavernous malformations, glomulin for glomuvenous malformations, TIE2 for multiple cutaneous and mucosal venous malformations, VEGFR-3, FOXC2, NEMO, SOX18 for lymphedema or related syndromes, ENG, ACVRLK1, MADH4 for HHT or related syndromes, NDP for Coats' disease, Notch3 for CADASIL, and PTEN for Proteus Syndrome. These findings have made genetic testing possible in some clinical cases, and may lead to the development of therapeutic strategies for vascular anomalies. Furthermore, these studies have identified critical genes involved in vascular morphogenesis, and provided fundamental understanding of the molecular mechanisms underlying vasculogenesis and angiogenesis.

Venogenic erectile dysfunction in Klippel-Trenaunay syndrome

OBJECTIVE

To report the management of erectile dysfunction (ED) secondary to Klippel-Trenaunay syndrome (KTS), a rare congenital vascular disease.

PATIENTS AND METHODS

Three men (mean age 33 years) with vasogenic ED secondary to KTS underwent venous ligation surgery of the affected veins. These men had tried various treatments for their ED, including phosphodiesterase type 5 inhibitors and intracavernosal injection therapy, with little success.

RESULTS

There was abnormal penile venous drainage in all three men, probably associated with congenital vascular malformation from KTS. After venous ligation the men were followed for 5 years and all reported good quality erections satisfactory for sexual intercourse.

CONCLUSION

ED in men with KTS may be due to venous drainage anomalies and if confirmed, venous ligation surgery should be performed as this gives the best chance of a complete resolution.

Is the E133K allele of VG5Q associated with Klippel-Trenaunay and other overgrowth syndromes?

BACKGROUND

It has been reported that the activating mutation, E133K, in the angiogenic factor VG5Q (formally named AGGF1) causes Klippel-Trenaunay Syndrome (KTS), a rare vascular disease associated with asymmetric overgrowth. This proposal followed from the observation that five out of 130 KTS patients were constitutionally heterozygous for VG5Q, E133K.

OBJECTIVE

To explore the possibility that VG5Q, and specifically E133K, is implicated in other mosaic overgrowth syndromes.

RESULTS

24 patients were analysed for this sequence change. One patient was constitutionally heterozygous for E133K. Analysis of both parents revealed that the patient's mother, who was healthy, also carried E133K. An analysis of 275 healthy controls showed that 3.3% (9/275) of the population were carriers of E133K.

CONCLUSIONS

The findings bring into question the assertion that VG5Q, E133K is a mutation and that it causes KTS.

Vascular update: Morphogenesis, tumors, malformations, and molecular dimensions

This vascular review is organized under the following headings: vasculogenesis and angiogenesis; vascular endothelial growth factors, their receptors, TIE receptors, and angiopoietins; other factors in blood vessel formation; parallel patterning in blood vessels and nerves; physiological and pathological neovascularization; the role of VEGF receptors in metastasis; anti-angiogenic therapy for tumors; association of blood vessels with fat; vascular malformations and vascular tumors; infantile hemangiomas; congenital hemangiomas; lymphatic malformations; molecular characteristics of some disorders with vascular malformations; Kasabach-Merritt phenomenon; Sturge-Weber syndrome, Klippel-Trenaunay syndrome, and Parkes Weber syndrome; diagnostic and laboratory studies; and future perspectives.