A new case of Klippel-Trenaunay-Weber (KTW) syndrome: evidence of autosomal dominant inheritance

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.

Late puerperal hemorrhage of a patient with Klippel-Trenaunay syndrome: A case report

INTRODUCTION

The Klippel-Trenaunay syndrome (KTS) is a rare congenital disorder. The obstetric course of women with KTS varies. Complications include bleeding, disseminated intravascular coagulation (DIC), thromboembolic events, etc. PATIENT CONCERNS:: Here, we report a case of late puerperal hemorrhage of a Chinese puerpera with KTS. The repeating severe hemorrhage, the DIC, and the Kasabach-Merrit syndrome made the treatment more difficult.

DIAGNOSIS

KTS is a mixed malformation with a vascular component that is characterized by abnormal development of veins, capillaries, and lymphatics. Our patient was first diagnosed with KTS at the last trimester of pregnancy.

INTERVENTIONS

Massive infusion of blood products, two laparotomies, as well as bilateral internal iliac artery embolization was carried out.

OUTCOMES

Although the patient survived from the life-threatening hemorrhage, she lost her uterus forever.

CONCLUSION

An interdisciplinary cooperation of obstetrician, anesthesiologist, vascular surgeon, and intensive care physician is highly recommended. Prophylactic anticoagulation is generally advised in the gestational and postpartum period.

Cerebral Cavernous Angioma Associated with Klippel Trenaunay Syndrome Treated with Gamma Knife Radiosurgery: Case Report and Literature Review

Klippel Trenaunay syndrome (KTS) is a rare, sporadic congenital syndrome characterized by cutaneous hemangiomas, venous varicosities, and osseous-soft tissue hypertrophy of the affected limb. It is genetically heterogeneous, and its clinical presentation is variable.

We report the case of a 13-year-old male with KTS, who presented with a cerebral cavernous angioma in the corpus callosum. To the best of our knowledge, this is the first reported case of its kind from Pakistan and the only known case in the literature of KTS to be treated with stereotactic radiosurgery.

The possibilities of shared genetic pathways between KTS and cavernous angiomas and the need for neurovascular scrutiny in patients with this syndrome are discussed.

Klippel-Trenaunay-Weber Syndrome with Atypical Presentation of Cerebral Cavernous Angioma: A Case Report and Literature Review

BACKGROUND

Klippel-Trenaunay-Weber syndrome (KTWS) is a rare syndrome characterized by the triad of cutaneous hemangiomas, venous varicosities, and osseous-soft tissue hypertrophy of the affected limb. Clinical manifestations, genetic testing, and radiologic imaging are the key steps in diagnosing this syndrome.

CASE DESCRIPTION

An 18-month-old boy was brought for follow-up brain magnetic resonance imaging (MRI) with a history of right lower limb hypertrophy, cutaneous varicosities, and hemangiomas diagnosed at birth. A baseline MRI at 12 months revealed multiple hemorrhagic lesions within the cerebrum, the largest in the right temporal lobe, which was treated surgically at the age of 18 months because of its rapid growth. This is the youngest patient with KTWS treated surgically for intracranial hemangiomas.

CONCLUSION

KTWS is a rare disease with a wide range of manifestations. Multisystemic evaluation of this group of patients should be performed to identify cavernous hemangiomas at the early stage of life and adequately treat them in the future. Treatment of KTWS patients with cavernous hemangiomas should not be different from the treatment of patients with any other hemangiomas, and surgical intervention should be considered on a case-to-case bases.

NEUROFIBROMATOSIS TYPE 1 AND OPTIC PATHWAY GLIOMA

PURPOSE

Evaluate the effectiveness of treatment of patients with optic pathway glioma.

MATERIALS AND METHODS

Comparison of literature research on neurofibromatosis and optic pathway glioma with a cohort of pediatric patients treated at the Childrens Ophthalmology Clinic of the University Hospital in Brno from January 2013 until June 2018.

DISCUSSION

The main challenge of this and other retrospective studies is variable intervals between ophthalmologic examinations. In some pediatric patients it is also difficult to objectively assess visual functions. The main risk factors are age at the time of treatment and tumor localization. Tumor progression itself does not always correlate with worse visual acuity outcomes, and it remains to be evaluated whether some patients would be better off without treatment. As of now, there are no clinical biomarkers able to predict impending visual acuity loss.

CONCLUSION

The cohort outcome agrees with literature. Chemotherapy remains a treatment of choice and its most likely outcome is visual acuity stabilization. In order to properly evaluate the treatments effectiveness, better collaboration between medical specialists and regular standardized ophthalmology examinations are required.

Pregnancy in women with Klippel-Trenaunay syndrome: Report of three pregnancies in a single patient and review of literature

Klippel-Trenaunay syndrome is characterised by vascular abnormality which increases the risk of thromboembolism and haemorrhage. Physiological changes in pregnancy pose an increased risk to these complications. Being an uncommon disorder, there is limited literature about the management of women with pregnancy and Klippel-Trenaunay syndrome. We report in detail two of three pregnancies in a woman with Klippel-Trenaunay syndrome who had repeated episodes of haematochezia leading to anaemia, managed with Argon laser Photo-Coagulation in pregnancy and also reviewed the complications and the management of pregnant women with Klippel-Trenaunay syndrome.

Analysis of Hemodynamics by MR-Angio and Embolization of Klippel-Trenaunay-Weber Syndrome: Five Year Follow-up

A newborn male child was admitted with hypoxemia, high output failure, hypertrophic right lower limb with a segmental pink naevus flammeus, lymphatic edema, subcutaneous varices and multiple arteriovenous fistulae (AVF) spinal and pelvine; findings of the Klippel-Trenaunay- / Parkes-Weber-Overlap Syndrom (KTW). Because of a threatening right heart insufficiency caused by the shuntvolume, the child was embolized as early as 5 months of age. In the course of 5 years, a total of 17 spinal and pelvic feeding arteries were occluded in 6 sessions using Histoacryl, Platincoils or Ethibloc. The low weight of the child's body (4.3 kg) and cardiac insufficiency (CI) limited the amount of contrast agent and fluid.

To reduce the amount of contrast agent used for diagnostic purposes we analyzed the pathological hemodynamics by magnetic resonance angiography (MRA).

Within 5 years normal bodily development took place with no sings of exponential growth of the affected leg. We understand the “newly formed” fistulae in the current angiography as a local hemodynamic activation of persistent primitive arteriovenous communication caused by mesodermal disturbances, the degree of which correlate with the prognosis.

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.

A port-wine stain in association with underlying syndrome

Klippel-Trenaunay syndrome (KTS) is a capillary-venous vascular malformation condition characterized by capillary malformation, soft tissue and bone hypertrophy, and varicosities. Here we present the case of a 29-year-old man who presented with port wine stain and recurrent ulcerations on his right leg. This leg was also larger than the left one. His condition was consistent with KTS. We discuss the pathogenesis, clinical presentation, complications, and treatment modalities of KTS.

Germline Mutations in RASA1 Are Not Found in Patients with Klippel-Trenaunay Syndrome or Capillary Malformation with Limb Overgrowth

The RASA1 gene encodes p120RASGAP, a multidomain cytoplasmic protein that acts as a negative regulator of the RAS signalling pathway. Heterozygous loss-of-function RASA1 mutations were identified in patients with Parkes Weber syndrome and multifocal capillary malformations. This syndrome is characterised by a capillary blush on an extremity, arteriovenous microfistulas, and bony and soft tissue hypertrophy. The aim of this study was to test RASA1 in 2 disorders characterised by asymmetric limb enlargement and vascular malformations, namely Klippel-Trenaunay syndrome and regional capillary malformation with overgrowth. We did not identify any clear pathogenic change in these patients. Thus, besides clinical and radiological criteria, RASA1 testing constitutes an additional tool to differentiate Parkes Weber syndrome of capillary malformation-arteriovenous malformation (CM-AVM) from overlapping disorders.

Dominant inheritance and intra-familial variations in the association of Sturge-Weber and Klippel-Trenaunay-Weber syndromes

This case report shows a genealogical study where a woman has limb hypertrophy and her son has an association of Sturge–Weber syndrome with Klippel–Trenaunay–Weber syndrome. The Sturge–Weber and Klippel–Trenaunay–Weber syndromes appear to be different manifestations of the same affliction. Familial aggregation exists and transmission may be almost imperceptible between generations. Identification of minor manifestations may prove to be a valuable contribution to genetic counseling of families and the prevention of new cases.

Klippel-trenaunay syndrome and pregnancy

Klippel-Trenaunay syndrome is a rare congenital vascular disorder, and only few cases have been described in pregnancy. We describe two cases, in one patient without complications, the other patient developed postpartum deep venous thrombosis.

Genetic Drift. Word smithing in medical genetics

Certain terms used in medical genetics and more often in other medical fields are in need of clarification. The terms cited are frequently misunderstood, mispronounced, and/or misspelled. The discussion includes two Latin-derived terms (genua valga and calvaria), one Greek-derived term (apoptosis), one gene-derived term (RUNX), one syndromic eponym (Kartagener syndrome), and three vascular eponyms (Klippel-Trenaunay syndrome, Parkes Weber syndrome, and Kasabach-Merritt phenomenon).

[Klippel-Trenaunay-Weber syndrome]

Klippel-Trenaunay syndrome is an inherited disorder that is known to affect the venous system. Besides venous pathologies, arterial stenosis and aneurysmatic dilatations are extremely rare. In this report, we present a 7-year-old boy with Klippel-Trenaunay-(Weber) syndrome who developed iliac and femoral artery aneurysms and stenosis at different levels in his lower limb.

Parkes Weber syndrome, vein of Galen aneurysmal malformation, and other fast-flow vascular anomalies are caused by RASA1 mutations

Capillary malformation-arteriovenous malformation (CM-AVM) is a newly recognized autosomal dominant disorder, caused by mutations in the RASA1 gene in six families. Here we report 42 novel RASA1 mutations and the associated phenotype in 44 families. The penetrance and de novo occurrence were high. All affected individuals presented multifocal capillary malformations (CMs), which represent the hallmark of the disorder. Importantly, one-third had fast-flow vascular lesions. Among them, we observed severe intracranial AVMs, including vein of Galen aneurysmal malformation, which were symptomatic at birth or during infancy, extracranial AVM of the face and extremities, and Parkes Weber syndrome (PKWS), previously considered sporadic and nongenetic. These fast-flow lesions can be differed from the other two genetic AVMs seen in hereditary hemorrhagic telangiectasia (HHT) and in phosphatase and tensin homolog (PTEN) hamartomatous tumor syndrome. Finally, some CM-AVM patients had neural tumors reminiscent of neurofibromatosis type 1 or 2. This is the first extensive study on the phenotypes associated with RASA1 mutations, and unravels their wide heterogeneity.

Conus medullaris spinal arteriovenous malformation in a patient with klippel-trenaunay-weber syndrome. A case report and review of the literature

SUMMARY

We describe a 24-year-old woman who presented with twice previously unverified subarachnoid hemorrhages from the conus medullaris spinal arteriovenous malformation with Parkes-Weber-syndrome. Spinal MRI examination is considered to be necessary for the diagnosis of Klippel-Trenaunay-Weber syndrome. For diagnosis of the spinal cord arteriovenous malformation, it is indispensable to search carefully for the presence of accompanying lesions. Transarterial glue embolizationis effective for the management of the spinal vascular lesion.

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.

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.

Klippel-Trenaunay-Type Syndrome in Pregnancy

INTRODUCTION

Klippel-Trenaunay-Type Syndrome (KTTS) is a rare congenital anomaly with variable expression and an unknown etiology characterized by capillary and venous malformations and hypertrophy of bone and soft tissue. Pregnancy has been rarely reported in patients with KTTS and since 1989 there have been only 13 case reports of pregnancy in women with KTTS reported in the literature. Concurrent pregnancy is associated with adverse perinatal outcomes. To the best of our knowledge this is the second reported, and largest, series of cases.

STUDY DESIGN

After a thorough review of the literature, the medical records of four obstetrical patients with KTTS were reviewed.

RESULTS

The obstetrical course of women with KTTS varies. Complications include bleeding, DIC, thromboembolic events, and pain.

CONCLUSIONS

The maternal and fetal risks associated with pregnancy in women with KTTS are proportional to the severity of disease, which can be exacerbated by pregnancy. Thoughtful preconceptional counseling, along with methodical and systematic intrapartum and postpartum care are keys to reducing mortality and morbidity.

Klippel-Trenaunay-Weber syndrome involving fetal thigh: prenatal presentations and outcomes

OBJECTIVES

We analyzed the prenatal presentations and perinatal outcomes of Klippel-Trenaunay-Weber syndrome involving fetal thigh in order to provide relevant information for prenatal counseling.

METHODS

We reviewed our own cases and searched for cases from Medline that met the criteria of Klippel-Trenaunay-Weber syndrome involving fetal thigh. Those with isolated hemangioma, hemangioendothelioma, and hemangiolymphangioma were excluded.

RESULTS

The cases of Klippel-Trenaunay-Weber syndrome involving fetal thigh, totaling 21, were collected for analysis. These included 19 cases from Medline search and two cases from our institution. The cases with lesions involving right thigh, left thigh, and both thighs were 12:8:1. The gender of affected fetuses was 9 male, 9 female, and 3 unknown. Among the 21 cases, 6 fetuses (28.57%, 6/21) had isolated thigh lesions, and the other 15 cases (71.43%, 15/21) had extensive lesions involving pelvis, abdomen, retroperitoneum, or thorax. Prenatal presentations varied with hypoechoic cystic mass with limb asymmetry, 95.23% (20/21); polyhydramnios, 38.09% (8/21); cardiomegaly, 19.04% (4/21); thick placenta, 9.52% (2/21); nonimmune hydrops fetalis, 9.52% (2/21); and oligohydramnios, 4.76% (1/21). Ten cases (47.62%, 10/21) underwent termination of pregnancy. For those who continued with pregnancy, the rate of complications with Kasabach-Merritt syndrome was 36.36% (4/11) and the mortality rate in the neonatal period was 45.45% (5/11). The causes of neonatal mortality in these five cases included consumption coagulopathy (Kasabach-Merritt syndrome), cardiac failure, sepsis, and prematurity.

CONCLUSIONS

Klippel-Trenaunay-Weber syndrome involving fetal thigh is rare. Our review showed that the location of involvement on the right thigh is more than on the left. Males and females were equally affected. Nearly three fourths of the cases had extensive involvement over other parts of the body. Prenatal ultrasound finding of a raised thigh mass of significant size and limb asymmetry were the most important features. The mortality rate was as high as 45.45% in the neonatal period.

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.

Neuroradiologic findings in a young patient with characteristics of Sturge-Weber syndrome and Klippel-Trenaunay syndrome

The patient presented here has extensive hemangiomata plana, especially on the right forehead, right upper eyelid, and right leg, as well as right leg hypertrophy and macrocephaly. Cerebral magnetic resonance imaging (MRI) showed abnormalities in only one occipital lobe consisting of focal cortical atrophy, leptomeningeal enhancement, and ipsilateral choroid plexus enlargement. Mental and motor development is normal, and he has no seizures. The parents are consanguineous. Leg hypertrophy associated with ipsilateral cutaneous vascular malformations is suggestive of Klippel-Trenaunay syndrome. The patient's central nervous system abnormalities on MRI and the hemangiomata plana on the ipsilateral upper eyelid and forehead point to Sturge-Weber syndrome. We conclude that the patient has an overlap syndrome between Klippel-Trenaunay syndrome and Sturge-Weber syndrome.

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.

Evaluation and management of pain in patients with Klippel-Trenaunay syndrome: a review

Klippel-Trenaunay syndrome (KTS) is a rare disorder that consists of a triad of capillary vascular malformation, venous malformations and/or varicose veins, and soft tissue and/or bony hypertrophy. Pain is a real and debilitating problem in these patients. We have observed 9 common causes of pain in KTS: (1) chronic venous insufficiency, (2) cellulitis, (3) superficial thrombophlebitis, (4) deep vein thrombosis, (5) calcification of vascular malformations, (6) growing pains, (7) intraosseous vascular malformation, (8) arthritis, and (9) neuropathic pain. The management of pain in patients with KTS depends on its cause. These patients are best evaluated initially in a center with an experienced multidisciplinary team that includes a primary health care provider, surgeons, and ancillary staff. The ongoing care of a patient with KTS often depends on a local provider who is more readily accessible to the patient but may not have the expertise of a large center to manage the complications of KTS. The purpose of this communication is to review the common causes of pain in these patients to provide local health care providers and patients and their families with appropriate management strategies.

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.

Factor VII deficiency and a copper metabolism disorder in a patient with Klippel-Trenaunay syndrome

We report on a patient with Klippel-Trenaunay (KT) syndrome, a factor VII deficiency and a copper metabolism disorder. The KT syndrome involved the left leg and, histologically, the liver. Dermatological examination, duplex ultrasonography and a skin and liver biopsy verified the KT syndrome. A long prothrombin time prompted clotting studies revealing a factor VII deficiency while the other factors were in the normal range. Further laboratory examinations showed a copper metabolism disorder similar to Wilson's disease with a low serum ceruloplasmin level, elevated copper concentration in the urine and increased copper deposition in the liver. Neither liver cirrhosis nor a Kayser-Fleischer corneal ring was present. Sequencing analysis of the Wilson's disease gene ATB7B showed no mutations. The occurrence of these three uncommon pathologies in a single patient has not been described to date, which may suggest a mutation in a hypothetical common regulatory gene leading to this unusual phenotype.

Klippel-Trenaunay-Weber (KTW) syndrome: the use of in utero magnetic resonance imaging (MRI) in a prospective diagnosis

The diagnosis of the Klippel-Trenaunay-Weber (KTW) syndrome is rarely made antenatally. We report the use of both ultrasound and in utero magnetic resonance imaging (MRI) in the prenatal diagnosis of this syndrome. This is the first report of the use of prenatal MRI in the diagnosis of this condition. There was concordance in the findings of both modalities, with limb hypertrophy, and multiple haemangiomata - both subcutaneous and internally - demonstrated with ultrasound and MRI. The patient elected to terminate the pregnancy because of associated oligohydramnios and a small fetal chest noted at 20 weeks. The postmortem examination confirmed the antenatal diagnosis.

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

Klippel-Trenaunay syndrome (KTS) is a disorder primarily characterized by capillary-venous vascular malformations associated with altered limb bulk and/or length. We report the identification of a balanced translocation involving chromosomes 8q22.3 and 14q13 in a patient with a vascular and tissue overgrowth syndrome consistent with KTS. We demonstrated that translocation t(8;14)(q22.3;q13) arose de novo. These data suggest that a pathogenic gene for a vascular and tissue overgrowth syndrome (KTS) may be located at chromosome 8q22.3 or 14q13. Fluorescence in situ hybridization (FISH) analysis was used to define the breakpoint on chromosome 8q22.3 to a <5-cM interval flanked by markers AFMA082TG9 and GATA25E10, and the 14q13 breakpoint within a 1-cM region between STSs WI-6583 and D14S989. This study provides a framework for the fine-mapping and ultimate cloning of a novel vascular gene at 8q22.3 or 14q13.

Loss of heterozygosity in human skin

Loss of heterozygosity (LOH) is a genetic mechanism by which a heterozygous somatic cell becomes either homozygous or hemizygous because the corresponding wild-type allele is lost. LOH has today been recognized as a major cause of malignant growth. This article gives a comprehensive review of skin disorders in which an origin from LOH has been either documented at the molecular level or postulated on the basis of clinical evidence. LOH has been shown to cause basal cell carcinoma, squamous cell carcinoma, and malignant melanoma, but this mechanism can likewise be taken as an important model to explain the origin of many other skin diseases such as benign hamartomas; type 2 segmental manifestation of autosomal dominant skin disorders; a pronounced segmental manifestation of acquired skin disorders with a polygenic background, superimposed on symmetric lesions of the usual type; paired mutant patches in the form of either allelic or nonallelic twin spotting; and the exceptional familial occurrence of some nevi, reflecting paradominant transmission. completion of this learning activity, readers should be familiar with the mechanism of LOH and its general significance for the biology of plants, animals, and humans. Participants should understand that this mechanism plays a crucial role not only in cutaneous malignant growth but also in the development of benign skin disorders, and they should be able to examine such diseases with a prepared mind to gain a better understanding of their origin.