Identification and molecular characterization of de novo translocation t(8;14)(q22.3;q13) associated with a vascular and tissue overgrowth syndrome

Klippel-Trénaunay-Weber Syndrome: Prenatal Diagnosis and Review of the Literature

Klippel-Trénaunay-Weber syndrome (KTW) is a rare congenital disease, representing a challenge in prenatal diagnosis due to overlapping characteristics with other syndromes and no specific genetic markers known to date. We have collected all the cases present in the literature on the prenatal diagnosis of KTW, emphasizing common ultrasound findings that can guide the clinician and genetics to the prenatal counseling. Thus, we collected all the information about the postnatal prognosis and the necessity for treatment. Our review of 44 cases highlights the typical common features: hemihypertrophy, predominantly affecting the right leg, with cystic lesions extending to the trunk or upper limbs and rare internal organ involvement. Prenatal complications, including hydrops and polyhydramnios, emphasize the need for a careful ultrasound follow-up. Despite no identified genetic mutation, genetic counseling and invasive testing are recommended. Mortality rate due to a severe complication known as Kasabach-Merritt syndrome, underlines the importance of early diagnosis and accurate management strategies. Prenatal diagnosis of KTW, guided by ultrasound findings and genetic counseling, could help with informed decision-making and optimal care planning.

Klippel-Trenaunay Syndrome: To Be or Not to Be Afraid

Klippel-Trenaunay syndrome (KTS) is a rare genetic syndrome comprising an abnormal development of soft tissues and the lymphovascular system with bony overgrowth, venous malformation, and port wine stains. We present an interesting case of a three-year-old child brought to our hospital with a swollen limb and raised skin lesions associated with bleeding from minor trauma. Most of the clinical characteristics of KTS were seen in our patient, including arteriovenous, soft tissue, capillary, and lymphatic abnormalities. The diagnosis of KTS is based on clinical examinations and imaging investigations. He had gross hypertrophy of the left lower limb with measurable lengthening compared to the opposite limb. Ultrasonography of the left limb revealed soft tissue hypertrophy with abnormal venous communication. The management of KTS is mainly symptomatic and should be approached conservatively if the patient has functional limbs without edema, bleeding, ulceration, or pain.

Prenatal Ultrasound Diagnosis of Klippel-Trenaunay Syndrome

Klippel-Trenaunay syndrome (KTS) is a very rare vascular malformation syndrome also referred to as a capillary-lymphatic-venous malformation with unknown aetiology. The aim of our paper is to highlight interesting images, regarding a rare case of foetal Klippel-Trenaunay syndrome diagnosed prenatally in our department and confirmed postnatally with a favourable evolution during the gestation and neonatal periods. This case was diagnosed at 26 weeks gestation and characterised through ultrasound by the presence of superficial multiple cystic structures of different sizes spreading over the left leg with hemihypertrophy and reduced mobility. The cystic lesions were spreading to the left buttock and the pelvic area. The right leg and upper limbs had normal appearance with good mobility. There were no signs of hyperdynamic circulation or foetal anaemia, but mild polyhydramnios was associated. The ultrasound findings were confirmed postnatally, the left leg presented multiple cystic lesions and port wine stains, and there was hypertrophy and fixed position, with favourable evolution at 6 months of life, when the size of the lesions began to decrease and the mobility of the leg improved.

Fetal Klippel-Trenaunay-Weber Syndrome: Antenatal Diagnosis and Postnatal Management

Context

Klippel-Trenaunay-Weber syndrome (KTWS) is a rare disease characterized by a triad of venous malformations, vascular skin nevus and asymmetric hypertrophy of bone and soft tissue. The spectrum of disease in utero varies from asymptomatic nevus flammeus to life threatening complications like Kasabach-Merritt phenomena.

Aim

The aim of this study was to review our experience of antenatal diagnosis of KTWS and it's postnatal management.

Settings and Design

This was a retrospective observational study of all pregnant women who were antenatally diagnosed with KTWS and postnatally confirmed at a tertiary care center in north India between 2012 and 2021.

Subjects and Methods

The electronic medical records were reviewed and data were collected regarding demographic information, obstetric history, clinical presentation, sonographic findings, mode of delivery, fetal outcome, and follow-up.

Results

During the study period, four fetuses were diagnosed with KTWS on sonography. Three women were multigravida whereas one was a primigravida. Two women opted for medical termination of pregnancy and one each had liveborn child and an intra-uterine fetal death. KTWS was confirmed in all cases. The liveborn child underwent treatment for the vascular malformation and is alive at 4 years of age.

Conclusions

This study attempts to add onto the available literature regarding the spectrum of prenatal presentations of KTWS. It emphasizes the importance of prenatal diagnosis and follow-up of the fetus/neonate.

Case report: PIK3CA somatic mutation leading to Klippel Trenaunay Syndrome and multiple tumors

We report a case of Klippel Trenaunay Syndrome that was monitored both clinically and molecularly over a period of 9 years. A somatic mosaic mutation of PIK3CA (p(E545G)) was identified using both cfDNA NGS liquid biopsy and tissue biopsy. At the age of 56, due to intervening clonal mutations in PIK3CA background, she developed a squamous cell carcinoma in the right affected leg which was treated surgically. Nine years later, lung bilateral adenocarcinoma arose on PIK3CA mutated tissues supported by different clonal mutations. One year later, the patient died from metastases led by a new FGFR3 clone unresponsive to standard-of-care, immunotherapy-based. Our results highlight the presence of a molecular hallmark underlying neoplastic transformation that occurs upon an angiodysplastic process and support the view that PIK3CA mutated tissues must be treated as precancerous lesions. Importantly, they remark the effectiveness of combining cfDNA NGS liquid and tissue biopsies to monitor disease evolution as well as to identify aggressive clones targetable by tailored therapy, which is more efficient than conventional protocols.

A case of chyluria with nephrotic-range proteinuria caused by lymphatic malformation, leading to a diagnosis of Klippel–Trenaunay syndrome

Klippel-Trenaunay syndrome (KTS) is a rare syndrome, which is clinically diagnosed by the presence of unilateral limb hypertrophy with vascular malformation including cutaneous capillaries, veins and lymphatic vessels. Most cases typically exhibit cutaneous manifestations such as port-wine stains and limb hypertrophy from infancy, but cases with mild manifestations may remain undiagnosed. We here report a case of KTS who was diagnosed by chance chyluria. A 15-year-old girl who exhibited hematochyluria with nephrotic-range proteinuria was referred to our hospital. She had been diagnosed as idiopathic scoliosis accompanied by left lower limb hypertrophy in the past. She noticed her milky urine for the first time two months before. Immediately thereafter, she noticed edema of her left leg. Hematochyluria with nephrotic-range proteinuria was found by our initial urine examination. Magnetic resonance imaging suggested venous or lymphatic malformation along the left common iliac vein at the retroperitoneal side. Lymphoscintigraphy showed congestion of radioisotope around backside of the pancreas to the left renal hilus, suggesting an existence of lymphostasis. Based on the findings, we diagnosed the patient as KTS. After admission, hematochyluria and proteinuria were decreased and became insignificant by three days with bed rest. Her left leg edema was reduced. After taking a guidance to avoid intensive exercise, she was discharged in two weeks. Because the present case exhibited mild manifestations, diagnosis was made by urine abnormalities for the first time. The case suggests that we should be aware of the presence of undiagnosed patients of KTS due to relatively mild manifestations.

The Klippel-Trénaunay Syndrome in 2022: Unravelling Its Genetic and Molecular Profile and Its Link to the Limb Overgrowth Syndromes

The Klippel-Trénaunay syndrome is an unusual syndrome of vascular and dermatologic manifestation in which patients demonstrate hemihypertrophy of the soft tissue and bones of one limb, cutaneous haemangiomas and varicosities in anatomically abnormal positions. Described in 1900 by two French physicians, the etiology remained unclear until recently, when evidence emerged that there was a genetic basis for this sporadic disorder. Genes that encoded pathological angiogenic factors and caused vascular dysmorphogenesis, explaining the molecular bases of this syndrome, were identified. Several angiogenic genes were identified but one gene, the AGGF1 (formerly VG5Q) gene, was seen in mutations involving patients diagnosed with Klippel-Trénaunay syndrome. Furthermore, this syndrome was also noted to have overlapping clinical features linked with the “overgrowth syndromes,” in which genetic mutations along somatic lines were identified. These involved The PI3K enzyme which forms part of the phosphoinositide 3–kinase pathway which is encoded by the PIK3CA-gene. This enzyme mediates embryonic cellular growth in-utero and diseases involved in this pathway are classified as members of the PIK3CA-related overgrowth syndrome. This paper reviews the status of what is now known about the molecular genetics of this unusual, but clinically challenging disorder and its differentiation from similar diseases, linked with the PIK3CA-gene and the related overgrowth syndromes.

Understanding Chronic Venous Disease: A Critical Overview of Its Pathophysiology and Medical Management

Chronic venous disease (CVD) is a multifactorial condition affecting an important percentage of the global population. It ranges from mild clinical signs, such as telangiectasias or reticular veins, to severe manifestations, such as venous ulcerations. However, varicose veins (VVs) are the most common manifestation of CVD. The explicit mechanisms of the disease are not well-understood. It seems that genetics and a plethora of environmental agents play an important role in the development and progression of CVD. The exposure to these factors leads to altered hemodynamics of the venous system, described as ambulatory venous hypertension, therefore promoting microcirculatory changes, inflammatory responses, hypoxia, venous wall remodeling, and epigenetic variations, even with important systemic implications. Thus, a proper clinical management of patients with CVD is essential to prevent potential harms of the disease, which also entails a significant loss of the quality of life in these individuals. Hence, the aim of the present review is to collect the current knowledge of CVD, including its epidemiology, etiology, and risk factors, but emphasizing the pathophysiology and medical care of these patients, including clinical manifestations, diagnosis, and treatments. Furthermore, future directions will also be covered in this work in order to provide potential fields to explore in the context of CVD.

Mechanisms of Lower Extremity Vein Dysfunction in Chronic Venous Disease and Implications in Management of Varicose Veins

Chronic venous disease (CVD) is a common venous disorder of the lower extremities. CVD can be manifested as varicose veins (VVs), with dilated and tortuous veins, dysfunctional valves and venous reflux. If not adequately treated, VVs could progress to chronic venous insufficiency (CVI) and lead to venous leg ulcer (VLU). Predisposing familial and genetic factors have been implicated in CVD. Additional environmental, behavioral and dietary factors including sedentary lifestyle and obesity may also contribute to CVD. Alterations in the mRNA expression, protein levels and proteolytic activity of matrix metalloproteinases (MMPs) have been detected in VVs and VLU. MMP expression/activity can be modulated by venous hydrostatic pressure, hypoxia, tissue metabolites, and inflammation. MMPs in turn increase proteolysis of different protein substrates in the extracellular matrix particularly collagen and elastin, leading to weakening of the vein wall. MMPs could also promote venous dilation by increasing the release of endothelium-derived vasodilators and activating potassium channels, leading to smooth muscle hyperpolarization and relaxation. Depending on VVs severity, management usually includes compression stockings, sclerotherapy and surgical removal. Venotonics have also been promoted to decrease the progression of VVs. Sulodexide has also shown benefits in VLU and CVI, and recent data suggest that it could improve venous smooth muscle contraction. Other lines of treatment including induction of endogenous tissue inhibitors of metalloproteinases (TIMPs) and administration of exogenous synthetic inhibitors of MMPs are being explored, and could provide alternative strategies in the treatment of CVD.

Genetic syndromes with vascular malformations - update on molecular background and diagnostics

Vascular malformations are present in a great variety of congenital syndromes, either as the predominant or additional feature. They pose a major challenge to the clinician: due to significant phenotype overlap, a precise diagnosis is often difficult to obtain, some of the malformations carry a risk of life threatening complications and, for many entities, treatment is not well established. To facilitate their recognition and aid in differentiation, we present a selection of notable congenital disorders of vascular system development, distinguishing between the heritable germinal and sporadic somatic mutations as their causes. Clinical features, genetic background and comprehensible description of molecular mechanisms is provided for each entity.

Prenatal diagnosis of Klippel-Trenaunay syndrome: Series of four cases and review of the literature

Klippel-Trenaunay syndrome is a rare disease with a classic triad of port wine stains, varicose veins, and bony and soft tissue hypertrophy of an extremity. The quality of life in these patients is significantly affected, making the prenatal diagnosis of Klippel-Trenaunay syndrome important. We present four prenatally diagnosed cases of this anomaly with a unique case of ectrodactyly of the hand in foetus with Klippel-Trenaunay syndrome. Such a combination has not been previously reported prenatally. A review of the literature for similar cases is also presented.

Klippel–Trenaunay Syndrome: Current Management

Klippel–Trenaunay syndrome (KTS) is a rare, sporadic, complex malformation characterized by the clinical triad of (1) capillary malformations (port wine stain); (2) soft tissue and bone hypertrophy or, occasionally, hypotrophy of usually one lower limb; and (3) atypical, mostly lateral varicosity. KTS is a mixed vascular malformation, with predominant capillary, venous and lymphatic components, without significant arteriovenous shunting. Management is largely conservative and the extent of diagnostic evaluation is determined by the planned treatment. Compression is the hallmark of conservative management; laser can be used to treat port wine stains. Imaging before vascular interventions must confirm venous anatomy and deep venous drainage. Techniques for ablation of superficial veins and malformations are individualized and may include sclerotherapy with alcohol or foam, endovenous thermal ablation or, as used most frequently in our practice, surgical stripping and phlebectomy. Intraoperative use of tourniquet will decrease bleeding, selective use of an inferior vena cava filter will prevent pulmonary embolism. A multidisciplinary approach to management of KTS is warranted.

Copy number variants in a population-based investigation of Klippel-Trenaunay syndrome

Klippel-Trenaunay syndrome (KTS) is a rare congenital vascular disorder that is thought to occur sporadically; however, reports of familial occurrence suggest a genetic component. We examined KTS cases to identify novel, potentially causal copy number variants (CNVs). We identified 17 KTS cases from all live-births occurring in New York (1998-2010). Extracted DNA was genotyped using Illumina microarrays and CNVs were called using PennCNV software. CNVs selected for follow-up had ≥10 single nucleotide polymorphisms (SNPs) and minimal overlap with in-house controls or controls from the Database of Genomic Variants. We identified 15 candidate CNVs in seven cases; among them a deletion in two cases within transcripts of HDAC9, a histone deacetylase essential for angiogenic sprouting of endothelial cells. One of them also had a duplication upstream of SALL3, a transcription factor essential for embryonic development that inhibits DNMT3A, a DNA methyltransferase responsible for embryonic de novo DNA methylation. Another case had a duplication spanning ING5, a histone acetylation regulator active during embryogenesis. We identified rare genetic variants related to chromatin modification which may have a key role in regulating vascular development during embryogenesis. Further investigation of their implications in the pathogenesis of KTS is warranted. © 2016 Wiley Periodicals, Inc.

Klippel-Trénaunay Syndrome: Need for Careful Clinical Classification

Klippel-Trénaunay syndrome (KTS) is a rare congenital malformation characterized by a triad of clinical presentations: (1) capillary malformations manifesting as a "port wine stain"; (2) limb hypertrophy; and (3) venous varicosities. It is distinguished from Parkes-Weber syndrome by the absence of substantial arteriovenous shunting. Due to the clinical implications of an arteriovenous fistula, differentiation between the two syndromes is important, as the prognosis and treatment greatly differ. We present a series of 5 cases of suspected KTS, while emphasizing the difficulties in distinguishing KTS from Parkes-Weber syndrome without diagnostic imaging and underscoring the importance of accurately classifying patients with the appropriate syndrome.

An unusual evolution of a case of Klippel-Trenaunay syndrome

Klippel-Trenaunay syndrome (KTS) is a rare congenital disorder. KTS can be diagnosed on the basis of any 2 of 3 features: cutaneous capillary malformations, soft tissue or bony hypertrophy and varicose veins. We present an unusual case of KTS complicated by an infection of venous ulcers of the lower limb by larvae. The treatment of infection was a complete debridement; however baseline treatment of KTS is still in evaluation.

Clinical Experience of the Klippel-Trenaunay Syndrome

Background

The Klippel-Trenaunay syndrome (KTS) is characterized by three clinical features, namely cutaneous capillary malformations, venous malformations, and soft tissue and/or bony hypertrophy of the extremities. The varied manifestations are attributed to the unpredictable clinical nature and prognosis of the syndrome. To elucidate the clinical characteristics of this disease, we reviewed a relatively large number of KTS patients who presented to our vascular anomalies center.

Methods

We conducted a retrospective study with 19 patients who were diagnosed with KTS and treated in our vascular anomalies clinic between 2003 and 2014, and examined their demographic characteristics, their clinical features, and the treatments administered.

Results

The sex distribution was balanced, with 9 (47%) males and 10 (53%) females. The mean follow-up period was 4.1 years (range, 7 months-9 years). Most of the patients received conservative treatments such as medication or physiotherapy. Compression therapies such as wearing of elastic garments/bandages were also administered, and surgical interventions were considered only when the patients became excessively symptomatic. Other treatments included laser therapy and sclerotherapy, and all the treatments were adjusted according to each case, tailored to the conditions of the individual patients.

Conclusions

KTS is an extremely rare, multifactorial disorder that induces widely varied symptoms. Because of this unique feature, plastic surgeons, when not careful, tend to attach a one-sided importance to typical symptoms such as limb hypertrophy or capillary malformation and thus overlook other symptoms and clinical features. KTS can be suspected in all infants who show capillary malformations or limb hypertrophy and require a multi-disciplinary approach for comprehensive management.

Klippel-trénaunay syndrome - a very rare and interesting syndrome

Klippel–Trénaunay syndrome (KTS or KT) is an infrequently seen dermatological syndrome, which is often viewed as a triad of vascular malformation (capillary malformations or port-wine brands), venous varicosity, and soft tissue and/or bony hypertrophy. We report a case of a 12-year-old male who presented to us with the symptoms of varicose plaques over both lower limbs and was diagnosed as a case of KTS. Management is normally conservative and includes stockings for compression of the branches to reduce edema because of chronic venous insufficiency; modern devices that cause on and off pneumatic compression; and rarely, surgical correction of varicose veins with lifelong follow-up. The orthopedic abnormalities are treated with epiphysiodesis in order to prevent (stop) overgrowing of limb and correction of bone deformity.

Genetics of hemangiomas, vascular malformations, and primary lymphedema

With improved genetic testing and genomic sequencing, abnormalities are increasingly being identified in affected or germline tissues in DNA of patients with vascular tumors, vascular malformations, and lymphedema. Recognition of the genetics of vascular anomalies should help clinicians make more specific diagnoses, anticipate diagnosis-specific morbidities, provide better genetic counseling, and have a better understanding of the pathogenesis of these anomalies. Growing pharmacologic options, including therapies targeted to specific mutations, with obvious parallels to cancer treatment now allow the pediatric hematologist-oncologist to assume a more prominent role in clinical care and research for patients with these diagnoses. We summarize genes and genetic loci that have been associated with vascular anomalies and offer guidelines for patient evaluations.

Biomolecular mechanisms in varicose veins development

Varicose veins (VVs) can be described as tortuous and dilated palpable veins, which are more than 3 mm in diameter. They are one of the clinical presentations of chronic venous disorders, which are a significant cause of morbidity. The prevalence of VVs has been estimated at 25-33% in women and 10-20% in men and is still increasing at an alarming rate. Family history, older age, female, pregnancy, obesity, standing occupations, and a history of deep venous thrombosis are the predominant risk factors. A great amount of factors are implicated in the pathogenesis of VVs, including changes in hydrostatic pressure, valvular incompetence, deep venous obstruction, ineffective function of calf muscle pump, biochemical and structural alterations of the vessel wall, extracellular matrix abnormalities, impaired balance between growth factors or cytokines, genetic alterations, and several other mechanisms. Nevertheless, the issue of pathogenesis in VVs is still not completely known, even if a great progress has been made in understanding their molecular basis. This kind of studies appears promising and should be encouraged, and perhaps the new insight in this matter may result in targeted therapy or possibly prevention.

Terminal deletion 2q37.3 in a patient with Klippel-Trenaunay-Weber syndrome

Klippel-Trenaunay-Weber syndrome (KTWS) is a rare congenital disorder, characterized by capillary, venous and lymphatic vascular malformations in association with bone and soft tissue hypertrophy. We report a KTWS patient with extensive hemangiomatosis of the right lower limb, trunk and upper limbs; bone and soft tissue hypertrophy of upper limbs, scapular girdle and right lower limb; and muscle atrophy on left lower limb with marked body asymmetry, scoliosis and toe malformations. These pathological features are associated with moderate mental retardation, mild renal and hepatic abnormalities. We identified by array CGH (Comparative Genomic Hybridization) a submicroscopic deletion 2q37.3 that could be related to impaired cognitive function. To our knowledge this is the first reported 2q37.3 microdeletion in a patient with KTWS.

Cutaneous vascular anomalies in the neonatal period

Vascular birthmarks can be difficult to diagnose in the perinatal period due to varied growth characteristics and similar initial appearances. Location and type of birthmark can provide signals that extracutaneous involvement may be a concern. This article provides a baseline framework that can help diagnose, define associations and guide workup and treatment in these neonates.

Prevalence of various congenital vascular malformations in patients with Klippel-Trenaunay syndrome

OBJECTIVE

Klippel-Trenaunay syndrome (KTS) is a condition defined by the association of three physical features: capillary malformation, varicosities, and hypertrophy of bony and soft tissues. However, KTS is characterized by congenital vascular malformations (CVMs) that are difficult to classify. Therefore, the present study was undertaken to analyze the various CVMs in patients with KTS.

METHODS

Sixty-one patients with KTS were enrolled, and their CVMs were divided into predominantly venous defects, predominantly lymphatic defects, and mixed vascular defects using the Hamburg Classification. Capillary malformations were subdivided into port-wine stain, telangiectasia, and angiokeratoma. Truncular and extratruncular vascular malformations were detected using duplex ultrasound and magnetic resonance imaging. Reflux in the superficial and deep venous systems was also evaluated.

RESULTS

Forty-five patients (74%) had predominantly venous defects, four (6%) had predominantly lymphatic defects, and 12 (20%) had mixed vascular defects. Capillary malformations were detected in 54 patients (89%), among which port-wine stain was the most predominant (40 patients, 66%), followed by telangiectasia (31 patients, 51%) and angiokeratoma (18 patients, 30%). Extratruncular venous malformations were detected in 47 patients (77%). In contrast, truncular venous malformations were found in 50 patients (82%). Among these, embryonic lateral marginal vein showed the highest occurrence, accounting for 53% (32 patients). However, reflux in this vein was detected in only nine patients (15%). Twelve patients (20%) had reflux in the great saphenous vein, and four (7%) had reflux in the small saphenous vein. Deep vein hypoplasia was found in seven patients (12%), and only five patients (8%) had deep vein aplasia. Extratruncular lymphatic malformations were found in 13 patients (21%) and truncular lymphatic malformations in 17 (28%).

CONCLUSIONS

Patients with KTS have a variety of CVMs, but both extratruncular and truncular venous malformations continue to be targets for intervention.

Pediatric epithelial salivary gland tumors: spectrum of histologies and cytogenetics at a children's hospital

There are conflicting reports regarding the relative frequency of benign and malignant epithelial salivary gland tumors in children. There are only a few reports of the cytogenetic abnormalities in the pleomorphic adenomas (PA) that arise in children, and even less information regarding the pleomorphic adenoma gene 1 (PLAG1) and high motility group A2 (HMGA2 ) histochemical staining in PAs, or their correlation with histologic types (stromal vs epithelial predominance). A retrospective 14 year review of epithelial salivary gland tumors encountered at a children's hospital identified 13 tumors: 12 PAs and 1 acinic cell carcinoma (ACC). No mucoepidermoid carcinomas were identified. Tumors arose in the parotid (7) and other sites (2 submandibular, 4 minor). Ten PAs in our cohort had cytogenetic studies. Four were normal, 5 involved 8q12, and 1 involved 12q13. Immunohistochemistry identified an additional 2 PAs with PLAG1 staining, and 5 additional PAs with HMGA2 staining. One tumor with ins(18;8)(q21.1;q12q22.2) had no PLAG1 staining, but stained with HMGA2. This ins(18;8) may not have involved the PLAG1 gene. There was no demonstrable correlation of 8q12/PLAG1 staining or 12q13/HMGA2 staining with histologic type. Thus we found abnormalities in either 8q12/PLAG1 staining or 12q13/HMGA2 staining in all PAs. The HMGA2 staining in 50% of PAs suggests that it may be more frequently involved in PAs than previously thought based on cytogenetic studies, at least in children.

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.

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.

Klippel-Trenaunay syndrome: diagnostic criteria and hypothesis on etiology

Klippel-Trenaunay syndrome (KTS) is a congenital malformation syndrome involving blood and lymph vessels and disturbed growth of bone and soft tissues. The clinical presentation can be extremely variable. An extensive literature search showed that various authors used many different diagnostic criteria. Uniform diagnostic criteria are an absolute prerequisite for successful molecular studies and for comparisons between various studies on almost any aspect of the disorder. Based on data from 3 unusually experienced colleagues and our experience, we propose restrictive diagnostic criteria, which still respect the extremely variable nature of KTS. Important aspects are that growth can be both increased and decreased, very small arteriovenous fistula can be present, and varicosities do not need to be present. Several hypotheses regarding cause and pathogenesis in KTS exist, but none explains all KTS characteristics completely. We propose yet another hypothesis which is at variance with the hypothesis of paradominant inheritance.

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.

Spinal arteriovenous malformations associated with Klippel-Trenaunay-Weber syndrome: a literature search and report of two cases

SUMMARY

Patients with Klippel-Trenaunay-Weber syndrome present with venous varices, cutaneous capillary malformations, and tissue hypertrophy, usually involving an extremity. A small but important subset also harbors arteriovenous malformations (AVMs) of the spine. We report 2 such cases, 1 with 3 concurrent spinal arteriovenous fistulas. These cases and our review of the literature emphasize the importance of screening the spine for AVMs. In addition, it is also important to investigate for the presence of multiple spinal AVMs.

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.

Fluorescence in situ hybridization in cardiovascular disease

Many human diseases are associated with cytogenetic abnormalities or chromosomal disorders including translocations, deletions, duplications, inversions, and other complicated chromosomal changes. Fluorescence in situ hybridization (FISH), a technique involving hybridization of labeled probes to chromosomes and detection of hybridization via fluorochromes, has become a popular method for identification and characterization of cytogenetic abnormalities. For FISH analysis, metaphase chromosomes are prepared by mitotic arrest and hypotonic shock, and denatured. Hybridization of digoxigenin- or biotin-labeled probes to these chromosomes is visualized using fluorochromes like fluorescein isothiocyanate and Texas Red. We have successfully applied FISH technology to the characterization of chromosome breakpoints involved in disease-associated cytogenetic abnormalities to identify candidate gene(s) for the disease. FISH is also widely used in clinical diagnosis of chromosomal disorders.

Klippel-Trenaunay-Syndrom

A 37-year-old man with Klippel-Trénaunay syndrome presented with an episode of painless severe gross hematuria. Magnetic resonance imaging (MRI) revealed vessels of significant diameter in the bladder wall. Diagnostic imaging is mandatory in order to be aware of the extent of the lesion as the bleeding identified intraoperatively may only be the "tip of the iceberg." If conservative means fail, laser coagulation should be the treatment of choice.

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.

Basic science and clinical aspects of vascular anomalies

PURPOSE OF REVIEW

Patients with vascular and lymphatic anomalies are often 'medical orphans' ascertained through distinct medical specialists. Multidisciplinary vascular anomalies programs provide focused expertise in diagnosis and treatment for patients. National and international workshops on vascular anomalies are fostering clinical and basic science research to enhance our understanding of vascular development and vascular anomalies. Herewith is presented an update of recent advances in the study of vascular/lymphatic anomalies.

RECENT FINDINGS

New original findings include (1) the identification of distinct cell surface markers and other cellular properties in hemangiomas and vascular malformations relevant to vascular development, (2) the discovery of novel genetic mutations and susceptibility genes in patients with vascular anomalies, (3) recognition of new risk stratifications and clinical issues for patients with hemangiomas and vascular malformations, and (4) the elucidation of sequelae from the disorders as well as side effects of recent and previous therapies for vascular anomalies.

SUMMARY

Vascular anomalies are an attractive model for the study of human disorders of vasculogenesis and angiogenesis. The etiology of these disorders is unclear and likely represents a multifactorial process. Clinical clues are leading to scientific investigations that may enable targeted therapies, prevention strategies, or both.

Biomedicine and diseases: the Klippel-Trenaunay syndrome, vascular anomalies and vascular morphogenesis

Vascular morphogenesis is a vital process for embryonic development, normal physiologic conditions (e.g. wound healing) and pathological processes (e.g. atherosclerosis, cancer). Genetic studies of vascular anomalies have led to identification of critical genes involved in vascular morphogenesis. A susceptibility gene, VG5Q (formally named AGGF1), was cloned for Klippel-Trenaunay syndrome (KTS). AGGF1 encodes a potent angiogenic factor, and KTS-associated mutations enhance angiogenic activity of AGGF1, defining 'increased angiogenesis' as one molecular mechanism for the pathogenesis of KTS. Similar studies have identified other genes involved in vascular anomalies as important genes for vascular morphogenesis, including TIE2, VEGFR-3, RASA1, KRIT1, MGC4607, PDCD10, glomulin, FOXC2, NEMO, SOX18, ENG, ACVRLK1, MADH4, NDP, TIMP3, Notch3, COL3A1 and PTEN. Future studies of vascular anomaly genes will provide insights into the molecular mechanisms for vascular morphogenesis, and may lead to the development of therapeutic strategies for treating these and other angiogenesis-related diseases, including coronary artery disease and cancer.

Identification and Molecular Characterization of a de novo Supernumerary Ring Chromosome 18 in a Patient with Klippel-Trenaunay Syndrome

Klippel-Trenaunay syndrome (KTS) is a congenital vascular disorder comprised of capillary, venous and lymphatic malformations associated with overgrowth of the affected tissues. In this study, we report the identification of a de novo supernumerary ring chromosome in a patient with mild mental retardation, long tapering fingers, elongated, thin feet and Klippel-Trenaunay syndrome (KTS). The ring marker chromosome was found to be mosaic, present in 24% of cells, and was later shown to be derived from chromosome 18, r(18). Fluorescence in situ hybridization (FISH) was used to define the breakpoints involved in the formation of r(18). The chromosome 18p breakpoint was localized between the markers WI-9619 and D18S1150, which is less than 10 cM to the centromere. The 18q breakpoint was localized between the centromere and BAC clone 666n19, which is a region of less than 40 kb. These data suggest that the r(18) mostly originated from 18p, with an estimated size of less than 10 cM. These studies identify and characterize a new marker chromosome 18, provide insights into the understanding of the relationships between the clinical phenotypes and marker chromosomes, and establish a framework for finding a potential vascular and/or overgrowth gene located on chromosome 18.

Klippel-Trenauney-Weber syndrome associated with hemoptysis

We report a case of Klippel-Trenaunay-Weber syndrome presenting with hemoptysis.

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

Angiogenic factors are critical to the initiation of angiogenesis and maintenance of the vascular network. Here we use human genetics as an approach to identify an angiogenic factor, VG5Q, and further define two genetic defects of VG5Q in patients with the vascular disease Klippel-Trenaunay syndrome (KTS). One mutation is chromosomal translocation t(5;11), which increases VG5Q transcription. The second is mutation E133K identified in five KTS patients, but not in 200 matched controls. VG5Q protein acts as a potent angiogenic factor in promoting angiogenesis, and suppression of VG5Q expression inhibits vessel formation. E133K is a functional mutation that substantially enhances the angiogenic effect of VG5Q. VG5Q shows strong expression in blood vessels and is secreted as vessel formation is initiated. VG5Q can bind to endothelial cells and promote cell proliferation, suggesting that it may act in an autocrine fashion. We also demonstrate a direct interaction of VG5Q with another secreted angiogenic factor, TWEAK (also known as TNFSF12). These results define VG5Q as an angiogenic factor, establish VG5Q as a susceptibility gene for KTS, and show that increased angiogenesis is a molecular pathogenic mechanism of KTS.

Rearrangement in the PITX2 and MIPOL1 genes in a patient with a t(4;14) chromosome

We report the molecular characterization of a patient with mild craniofacial and acallosal central nervous system midline defects and a t(4;14)(q25)(q13) chromosome. With the use of flow sorted chromosomes, the translocation breakpoint junction was defined within a 100 kb region with markers mapping to chromosomes 4q25 and 14q13. Analysis of genomic sequences demonstrated that the breakpoint junction at 14q13 was within the third intron of the 5' untranslated region of the MIPOL1 gene (GI: 22048098). On chromosome 4q25, two breakpoint junctions were found. One was about 47 kb distal to the 5' end of a putative gene (GI: 8923996) with unknown function but with partial similarity to kinases, and a second breakpoint was within the 3' end of the PITX2 gene (GI: 21361182) that resulted in the deletion of exons 6 and 7 of this gene. We also searched for microdeletions in a panel of candidate genes mapping within 2 Mb of the translocation breakpoint junction on chromosomes 4 and 14, however, no evidence for deletions or rearrangements was found. The finding of two breaks on chromosome 4q25 suggests a complex microrearrangement, such as an inversion, in addition to a translocation in this patient.