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The TSC complex is the cognate GTPase-activating protein (GAP) for the small GTPase Rheb and a crucial regulator of the mechanistic target of rapamycin complex 1 (mTORC1). Mutations in the TSC1 and TSC2 subunits of the complex cause tuberous sclerosis complex (TSC). We present the crystal structure of the catalytic asparagine-thumb GAP domain of TSC2. A model of the TSC2-Rheb complex and molecular dynamics simulations suggest that TSC2 Asn1643 and Rheb Tyr35 are key active site residues, while Rheb Arg15 and Asp65, previously proposed as catalytic residues, contribute to the TSC2-Rheb interface and indirectly aid catalysis. The TSC2 GAP domain is further stabilized by interactions with other TSC2 domains. We characterize TSC2 variants that partially affect TSC2 functionality and are associated with atypical symptoms in patients, suggesting that mutations in TSC1 and TSC2 might predispose to neurological and vascular disorders without fulfilling the clinical criteria for TSC., Competing Interests: Declaration of Interests The authors declare no conflict of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Red blood cell (RBC) deformability is altered in inherited RBC disorders but the mechanism behind this is poorly understood. Here, we explored the molecular, biophysical, morphological, and functional consequences of α-spectrin mutations in a patient with hereditary elliptocytosis (pEl) almost exclusively expressing the Pro260 variant of SPTA1 and her mother (pElm), heterozygous for this mutation. At the molecular level, the pEI RBC proteome was globally preserved but spectrin density at cell edges was increased. Decreased phosphatidylserine vs. increased lysophosphatidylserine species, and enhanced lipid peroxidation, methemoglobin, and plasma acid sphingomyelinase (aSMase) activity were observed. At the biophysical level, although membrane transversal asymmetry was preserved, curvature at RBC edges and rigidity were increased. Lipid domains were altered for membrane:cytoskeleton anchorage, cholesterol content and response to Ca 2+ exchange stimulation. At the morphological and functional levels, pEl RBCs exhibited reduced size and circularity, increased fragility and impaired membrane Ca 2+ exchanges. The contribution of increased membrane curvature to the pEl phenotype was shown by mechanistic experiments in healthy RBCs upon lysophosphatidylserine membrane insertion. The role of lipid domain defects was proved by cholesterol depletion and aSMase inhibition in pEl. The data indicate that aberrant membrane content and biophysical properties alter pEl RBC morphology and functionality.

Here, we present first draft genome sequence of the trypanosomatid Herpetomonas muscarum ingenoplastis . This parasite was isolated repeatedly in the black blowfly, Phormia regina , and it forms a phylogenetically distinct clade in the Trypanosomatidae family., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Context: The National Institute of Excellence in Health and Social Services (INESSS), which functions as the Québec health technology assessment (HTA) agency, tested a new way to engage patients along with health-care professionals in the co-construction of recommendations regarding implantable cardioverter-defibrillator replacement., Objective: The objective of this article was to describe the process of co-construction of recommendations and to propose methods of building best practices for patient involvement (PI) in HTA., Design: Throughout the process, documents were collected and participant observations were made. Individual interviews were conducted with patients, health-care professionals and the INESSS scientific team, from January to March 2018., Results: Three committees were established: an expert patient committee to reflect on patient experience literature; an expert health professional committee to reflect on medical literature; and a co-construction committee through which both patients and health-care professionals contributed to develop the recommendations. The expert patients validated and contextualized a literature review produced by the scientific team. This allowed the scientists to consider aspects related to the patient experience and to integrate the feedback from patients into HTA recommendations. The most important factor contributing to a positive PI experience was the structured methodology for selecting patient participants, and a key factor that inhibited the process was a lack of training in PI on the part of the scientific team., Conclusions: This experience demonstrates that it is possible to co-construct recommendations, even for technically complex HTA subjects, through a more democratic process than usual which led to more patient-focused guidance., (© 2019 The Authors Health Expectations published by John Wiley & Sons Ltd.)

Background: Capillary malformation-arteriovenous malformation is an autosomal dominant disorder, characterised by capillary malformations and increased risk of fast-flow vascular malformations, caused by loss-of-function mutations in the RASA1 or EPHB4 genes. Around 25% of the patients do not seem to carry a germline mutation in either one of these two genes. Even if other genes could be involved, some individuals may have mutations in the known genes that escaped detection by less sensitive techniques. We tested the hypothesis that mosaic mutations could explain some of previously negative cases., Methods: DNA was extracted from peripheral blood lymphocytes, saliva or vascular malformation tissues from four patients. RASA1 and EPHB4 coding regions and exon/intron boundaries were analysed by targeted custom gene panel sequencing. A second panel and/or Sanger sequencing were used to confirm the identified mutations., Results: Four distinct mosaic RASA1 mutations, with an allele frequency ranging from 3% to 25%, were identified in four index patients with classical capillary malformation-arteriovenous malformation phenotype. Three mutations were known, one was novel. In one patient, a somatic second hit was also identified. One index case had three affected children, illustrating that the mosaicism was also present in the germline., Conclusion: This study shows that RASA1 mosaic mutations can cause capillary malformation-arteriovenous malformation. Thus, highly sensitive sequencing techniques should be considered as diagnostic tools, especially for patients with no family history. Even low-level mosaicism can cause the classical phenotype and increased risk for offspring. In addition, our study further supports the second-hit pathophysiological mechanism to explain the multifocality of vascular lesions in this disorder., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

We herein report the case of a 3-year-old girl with atypical congenital right upper limb lymphedema who developed an angiosarcoma. Only a few cases have been reported following congenital form of lymphedema and only 4 in such a young child. We also summarize all cases of angiosarcoma associated with congenital lymphedema reported in the literature., (© 2018 Wiley Periodicals, Inc.)

Primary lymphedema is due to developmental and/or functional defects in the lymphatic system. It may affect any part of the body, with predominance for the lower extremities. Twenty-seven genes have already been linked to primary lymphedema, either isolated, or as part of a syndrome. The proteins that they encode are involved in VEGFR3 receptor signaling. They account for about one third of all primary lymphedema cases, underscoring the existence of additional genetic factors. We used whole-exome sequencing to investigate the underlying cause in a non-consanguineous family with two children affected by lymphedema, lymphangiectasia and distinct facial features. We discovered bi-allelic missense mutations in ADAMTS3. Both were predicted to be highly damaging. These amino acid substitutions affect well-conserved residues in the prodomain and in the peptidase domain of ADAMTS3. In vitro, the mutant proteins were abnormally processed and sequestered within cells, which abolished proteolytic activation of pro-VEGFC. VEGFC processing is also affected by CCBE1 mutations that cause the Hennekam lymphangiectasia-lymphedema syndrome syndrome type1. Our data identifies ADAMTS3 as a novel gene that can be mutated in individuals affected by the Hennekam syndrome. These patients have distinctive facial features similar to those with mutations in CCBE1. Our results corroborate the recent in vitro and murine data that suggest a close functional interaction between ADAMTS3 and CCBE1 in triggering VEGFR3 signaling, a cornerstone for the differentiation and function of lymphatic endothelial cells., (© The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Introduction: GATA2 mutations are associated with several conditions, including Emberger syndrome which is the association of primary lymphedema with hematological anomalies and an increased risk for myelodysplasia and leukemia., Objective: To describe a family with Emberger syndrome with incomplete penetrance., Methods: A DNA sequencing of GATA2 gene was performed in the parents and offspring (five individuals in total)., Results: The family consisted of 5 individuals with a GATA2 null mutation (c.130G>T, p.Glu44*); three of them were affected (two of which were deceased) while two remained unaffected at the age of 40 and 13 years old. The three affected siblings (two boys and one girl) presented with lymphedema of the lower limbs, recurrent warts, epistaxis and recurrent infections. Two died due to hematological abnormalities (AML and pancytopenia). In contrast, the two other family members who carry the same mutation (the mother and one brother) have not presented any symptoms and their blood tests remain normal., Discussion: Incomplete penetrance may indicate that GATA2 haploinsufficiency is not enough to produce the phenotype of Emberger syndrome. It could be useful to perform whole exome or genome sequencing, in cases where incomplete penetrance or high variable expressivity is described, in order to probably identify specific gene interactions that drastically modify the phenotype. In addition, skewed gene expression by an epigenetic mechanism of gene regulation should also be considered.

Objectives: It has often been reported that cognitive training has limited transfer effects. The present study addresses training context variability as a factor that could increase transfer effects, as well as the manifestation through time of transfer effects., Method: Fifty-eight older adults were assigned to an active placebo or two dual-task training conditions, one in which the training context varies between sessions (heterogeneous training) and the other in a fixed training context (homogeneous training). Transfer was assessed with near and far-modality transfer tasks., Results: Results show that heterogeneous and homogeneous training led to larger near-modality transfer effects than an active placebo (computer lessons). Transfer effects were roughly comparable in both training groups, but heterogeneous training led to a steeper improvement of the dual-task coordination learning curve within training sessions. Also, results indicated that dual-task cost did not improve in the active placebo group from the pre- to the post-training sessions., Discussion: Heterogeneous training showed modest advantages over homogeneous training. Results also suggest that transfer effects on dual-task cost induced by training take place early on in the post-training session. These findings provide valuable insights on benefits arising from variability in the training protocol for maximizing transfer effects., (© The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The collagen- and calcium-binding EGF domains 1 (CCBE1) protein is necessary for lymphangiogenesis. Its C-terminal collagen-like domain was shown to be required for the activation of the major lymphangiogenic growth factor VEGF-C (Vascular Endothelial Growth Factor-C) along with the ADAMTS3 (A Disintegrin And Metalloproteinase with Thrombospondin Motifs-3) protease. However, it remained unclear how the N-terminal domain of CCBE1 contributed to lymphangiogenic signaling. Here, we show that efficient activation of VEGF-C requires its C-terminal domain both in vitro and in a transgenic mouse model. The N-terminal EGF-like domain of CCBE1 increased VEGFR-3 signaling by colocalizing pro-VEGF-C with its activating protease to the lymphatic endothelial cell surface. When the ADAMTS3 amounts were limited, proteolytic activation of pro-VEGF-C was supported by the N-terminal domain of CCBE1, but not by its C-terminal domain. A single amino acid substitution in ADAMTS3, identified from a lymphedema patient, was associated with abnormal CCBE1 localization. These results show that CCBE1 promotes VEGFR-3 signaling and lymphangiogenesis by different mechanisms, which are mediated independently by the two domains of CCBE1: by enhancing the cleavage activity of ADAMTS3 and by facilitating the colocalization of VEGF-C and ADAMTS3. These new insights should be valuable in developing new strategies to therapeutically target VEGF-C/VEGFR-3-induced lymphangiogenesis.

Background: Microcephaly with or without chorioretinopathy, lymphedema, or mental retardation syndrome (MCLMR) is a rare autosomal dominant disorder with variable expressivity. It is characterized by mild-to-severe microcephaly, often associated with intellectual disability, ocular defects and lymphedema. It can be sporadic or inherited. Eighty-seven patients have been described to carry a mutation in KIF11, which encodes a homotetrameric motor kinesin, EG5., Methods: We tested 23 unreported MCLMR index patients for KIF11. We also reviewed the clinical phenotypes of all our patients as well as of those described in previously published studies., Results: We identified 14 mutations, 12 of which are novel. We detected mutations in 12 affected individuals, from 6 out of 6 familial cases, and in 8 out of 17 sporadic patients. Phenotypic evaluation of patients (our 26 + 61 earlier published = 87) revealed microcephaly in 91%, eye anomalies in 72%, intellectual disability in 67% and lymphedema in 47% of the patients. Unaffected carriers were rare (4 out of 87: 5%). Family history is not a requisite for diagnosis; 31% (16 out of 52) were de novo cases., Conclusions: All inherited cases, and 50% of sporadic cases of MCLMR are due to germline KIF11 mutations. It is possible that mosaic KIF11 mutations cause the remainder of sporadic cases, which the methods employed here were not designed to detect. On the other hand, some of them might have another mimicking disorder and genetic defect, as microcephaly is highly heterogeneous. In aggregate, KIF11 mutations likely cause the majority, if not all, of MCLMR.

Lymphatic anomalies include a variety of developmental and/or functional defects affecting the lymphatic vessels: sporadic and familial forms of primary lymphedema, secondary lymphedema, chylothorax and chylous ascites, lymphatic malformations, and overgrowth syndromes with a lymphatic component. Germline mutations have been identified in at least 20 genes that encode proteins acting around VEGFR-3 signaling but also downstream of other tyrosine kinase receptors. These mutations exert their effects via the RAS/MAPK and the PI3K/AKT pathways and explain more than a quarter of the incidence of primary lymphedema, mostly of inherited forms. More common forms may also result from multigenic effects or post-zygotic mutations. Most of the corresponding murine knockouts are homozygous lethal, while heterozygotes are healthy, which suggests differences in human and murine physiology and the influence of other factors.

Lymphedema is caused by dysfunction of lymphatic vessels, leading to disabling swelling that occurs mostly on the extremities. Lymphedema can be either primary (congenital) or secondary (acquired). Familial primary lymphedema commonly segregates in an autosomal dominant or recessive manner. It can also occur in combination with other clinical features. Nine mutated genes have been identified in different isolated or syndromic forms of lymphedema. However, the prevalence of primary lymphedema that can be explained by these genetic alterations is unknown. In this study, we investigated 7 of these putative genes. We screened 78 index patients from families with inherited lymphedema for mutations in FLT4, GJC2, FOXC2, SOX18, GATA2, CCBE1, and PTPN14. Altogether, we discovered 28 mutations explaining 36% of the cases. Additionally, 149 patients with sporadic primary lymphedema were screened for FLT4, FOXC2, SOX18, CCBE1, and PTPN14. Twelve mutations were found that explain 8% of the cases. Still unidentified is the genetic cause of primary lymphedema in 64% of patients with a family history and 92% of sporadic cases. Identification of those genes is important for understanding of etiopathogenesis, stratification of treatments and generation of disease models. Interestingly, most of the proteins that are encoded by the genes mutated in primary lymphedema seem to act in a single functional pathway involving VEGFR3 signaling. This underscores the important role this pathway plays in lymphatic development and function and suggests that the unknown genes also have a role.

Inherited vascular malformations are commonly autosomal dominantly inherited with high, but incomplete, penetrance; they often present as multiple lesions. We hypothesized that Knudson's two-hit model could explain this multifocality and partial penetrance. We performed a systematic analysis of inherited glomuvenous malformations (GVMs) by using multiple approaches, including a sensitive allele-specific pairwise SNP-chip method. Overall, we identified 16 somatic mutations, most of which were not intragenic but were cases of acquired uniparental isodisomy (aUPID) involving chromosome 1p. The breakpoint of each aUPID is located in an A- and T-rich, high-DNA-flexibility region (1p13.1-1p12). This region corresponds to a possible new fragile site. Occurrences of these mutations render the inherited glomulin variant in 1p22.1 homozygous in the affected tissues without loss of genetic material. This finding demonstrates that a double hit is needed to trigger formation of a GVM. It also suggests that somatic UPID, only detectable by sensitive pairwise analysis in heterogeneous tissues, might be a common phenomenon in human cells. Thus, aUPID might play a role in the pathogenesis of various nonmalignant disorders and might explain local impaired function and/or clinical variability. Furthermore, these data suggest that pairwise analysis of blood and tissue, even on heterogeneous tissue, can be used for localizing double-hit mutations in disease-causing genes., (Copyright © 2013 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Two hereditary syndromes, lymphedema-distichiasis (LD) syndrome and blepharo-chelio-dontic (BCD) syndrome include the aberrant growth of eyelashes from the meibomian glands, known as distichiasis. LD is an autosomal dominant syndrome primarily characterized by distichiasis and the onset of lymphedema usually during puberty. Mutations in the forkhead transcription factor FOXC2 are the only known cause of LD. BCD syndrome consists of autosomal dominant abnormalities of the eyelid, lip, and teeth, and the etiology remains unknown. In this report, we describe a proband that presented with distichiasis, microcephaly, bilateral grade IV vesicoureteral reflux requiring ureteral re-implantation, mild intellectual impairment and apparent glomuvenous malformations (GVM). Distichiasis was present in three generations of the proband's maternal side of the family. The GVMs were severe in the proband, and maternal family members exhibited lower extremity varicosities of variable degree. A GLMN (glomulin) gene mutation was identified in the proband that accounts for the observed GVMs; no other family member could be tested. TIE2 sequencing revealed no mutations. In the proband, an additional submicroscopic 265 kb contiguous gene deletion was identified in 16q24.3, located 609 kb distal to the FOXC2 locus, which was inherited from the proband's mother. The deletion includes the C16ORF95, FBXO31, MAP1LC3B, and ZCCHC14 loci and 115 kb of a gene desert distal to FOXC2 and FOXL1. Thus, it is likely that the microcephaly, distichiasis, vesicoureteral, and intellectual impairment in this family may be caused by the deletion of one or more of these genes and/or deletion of distant cis-regulatory elements of FOXC2 expression., (Copyright © 2012 Wiley Periodicals, Inc.)

Glomuvenous malformations are hereditary vascular anomalies, usually without extracutaneous involvement. We report two cases of extensive thoracic plaque-type glomuvenous malformation in newborns who had previously been diagnosed in utero with pleural effusion and ascites, suggesting a pathogenic link between the two conditions., (© 2010 Wiley Periodicals, Inc.)

The development and bicultural validation of the New Sexual Satisfaction Scale (NSSS)--a 20 item, multidimensional, composite measure of sexual satisfaction--is presented. The development of the scale was based on a five-dimension, conceptual model that emphasized the importance of multiple domains of sexual behavior including sexual sensations, sexual awareness and focus, sexual exchange, emotional closeness, and sexual activity. Scale construction and validation were carried out using seven independent samples with over 2,000 participants aged 18 to 55 in Croatia and the United States. Primary data collection was completed using online survey tools. Analyses did not confirm the proposed conceptual framework but suggested a two-dimensional structure focusing on self ("ego-centered") and the other (a "partner- and sexual activity-centered" factor) domains, each containing items representing all five conceptual dimensions. Scale reliability (k = 20) was satisfactory for all samples, and construct validity was confirmed in both cultures. The NSSS was also found to have acceptable one-month stability. It is suggested that the NSSS may be a useful tool for assessing sexual satisfaction regardless of a person's gender, sexual orientation, and relationship status.

Vascular malformations are localized defects of vascular development. They usually affect a limited number of vessels in a restricted area of the body. Although most malformations are sporadic, inheritance is observed, enabling genetic analysis. Usually, sporadic forms present with a single lesion whereas multiple lesions are observed in familial cases. The last decade has seen unraveling of several causative genes and beginning of elucidation of the pathophysiological pathways involved in the inherited forms. In parallel, definition of the clinical phenotypes has improved and disorders such as Parkes-Weber syndrome (PKWS), first thought to be sporadic, is now known to be part of a more common inheritable phenotype. In addition, the concept of double-hit mechanism that we proposed earlier to explain the incomplete penetrance, variable expressivity and multifocality of lesions in inherited venous anomalies is now becoming confirmed, as some somatic mutations have been identified in venous, glomuvenous and cerebral cavernous malformations. It is thus tempting to suggest that familial forms of vascular malformations follow paradominant inheritance and that sporadic forms, the etiopathogenic causes of which are still unelucidated, are caused by somatic mutations in the same genes.

Due to their geographical mobility and long periods of separation from intimate partners, migrant workers are at increased risk for a variety of sexually transmitted infections (STIs) including HIV/AIDS. This study sought to investigate patterns in HIV/AIDS related knowledge, attitudes and sexual behaviour in migrant workers in Croatia. In 2003, 566 male migrant workers were recruited during regular required medical examinations and surveyed at seven locations throughout the country. Each participant was asked to complete a self-administered KABP (sexual knowledge, attitudes, beliefs and practices) questionnaire. The average age of respondents was 38.2 years and the majority worked as seafarers (77.3%) and construction workers (20.5%). Only 18.5% of respondents were able to correctly answer all 13 questions assessing knowledge of HIV/AIDS. Seafarers reported higher levels of knowledge than did construction workers. The average respondent reported having had two sexual partners in the last 12 months, with slightly over half of the respondents (55.3%) reporting condom use at their last intercourse with a casual partner. One fifth of the respondents (20.3%) who reported having had intercourse with a sex worker during the last year reported not using condoms at last intercourse. The number of sexual partners was correlated with age, marital status, faith in God, and personal HIV risk assessment. Attitudes toward condom use, co-workers' HIV/AIDS concerns and the duration of migrant status (within the last two years) were shown to be significant correlates of condom use at last intercourse with a casual partner. The effect of HIV/AIDS related knowledge on analyzed behaviors did not reach statistical significance. Inadequate patterns of migrant workers' condom use, gaps in knowledge about HIV transmission and modes of protection, as well as widespread ignorance regarding available anonymous HIV testing found by this study suggest a critical need for expert intervention to avert the potential for an increase in new HIV/AIDS cases. A coordinated, systematic campaign for HIV/AIDS prevention among Croatian migrant workers should focus on increasing peer communication about HIV/AIDS, especially among younger migrant workers, and on reducing the frequency of sexual risk taking.

Background: Glomuvenous malformation (GVM) ("familial glomangioma") is a localised cutaneous vascular lesion histologically characterised by abnormal smooth muscle-like "glomus cells" in the walls of distended endothelium lined channels. Inheritable GVM has been linked to chromosome 1p21-22 and is caused by truncating mutations in glomulin. A double hit mutation was identified in one lesion. This finding suggests that GVM results from complete localised loss of function and explains the paradominant mode of inheritance., Objective: To report on the identification of a mutation in glomulin in 23 additional families with GVM., Results: Three mutations are new; the others have been described previously. Among the 17 different inherited mutations in glomulin known up to now in 43 families, the 157delAAGAA mutation is the most common and was present in 21 families (48.8%). Mutation 108C-->A was found in five families (11.8%), and the mutations 554delA+556delCCT and 1179delCAA were present together in two families (4.7% each). Polymorphic markers suggested a founder effect for all four mutations., Conclusions: Screening for these mutations should lead to a genetic diagnosis in about 70% of patients with inherited GVM. So far, a mutation in glomulin has been found in all GVM families tested, thus demonstrating locus homogeneity.

Mutations in the glomulin gene result in dominantly inherited vascular lesions of the skin known as glomuvenous malformations (GVMs). These lesions are histologically distinguished by their distended vein-like channels containing characteristic 'glomus cells', which appear to be incompletely or improperly differentiated vascular smooth muscle cells (VSMCs). The function of glomulin is currently unknown. We studied glomulin expression during murine development (E9.5 days post-coitum until adulthood) by non-radioactive in situ hybridization. Glomulin was first detected at E10.5 dpc in cardiac outflow tracts. Later, it showed strong expression in VSMCs as well as a limited expression in the perichondrium. At E11.5-14.5 dpc glomulin RNA was most abundant in the walls of the large vessels. At E16.5 dpc expression was also detectable in smaller arteries and veins. The high expression of glomulin in murine vasculature suggests an important role for glomulin in blood vessel development and/or maintenance, which is supported by the vascular phenotype seen in GVM patients with mutations in this gene.

Vascular anomalies are localized defects of the vasculature, and usually affect a limited number of vessels in a restricted area of the body. They are subdivided into vascular malformations and vascular tumours. Most are sporadic, but Mendelian inheritance is observed in some families. By genetic analysis, several causative genes have been identified during the last 10 years. This has shed light into the pathophysiological pathways involved. Interestingly, in most cases, the primary defect seems to affect the characteristics of endothelial cells. Only mutations in the glomulin gene, responsible for hereditary glomuvenous malformations, are thought to directly affect vascular smooth-muscle cells.

Glomuvenous malformations (GVMs) are cutaneous venous lesions characterized by the presence of smooth-muscle--like glomus cells in the media surrounding distended vascular lumens. We have shown that heritable GVMs link to a 4--6-cM region in chromosome 1p21-22. We also identified linkage disequilibrium that allowed a narrowing of this VMGLOM locus to 1.48 Mb. Herein, we report the identification of the mutated gene, glomulin, localized on the basis of the YAC and PAC maps. An incomplete cDNA sequence for glomulin had previously been designated "FAP48," for "FKBP-associated protein of 48 kD." The complete cDNA for glomulin contains an open reading frame of 1,785 nt encoding a predicted protein of 68 kD. The gene consists of 19 exons in which we identified 14 different germline mutations in patients with GVM. In addition, we found a somatic "second hit" mutation in affected tissue of a patient with an inherited genomic deletion. Since all but one of the mutations result in premature stop codons, and since the localized nature of the lesions could be explained by Knudson's two-hit model, GVMs are likely caused by complete loss of function of glomulin. The abnormal phenotype of vascular smooth-muscle cells (VSMCs) in GVMs suggests that glomulin plays an important role in differentiation of these cells--and, thereby, in vascular morphogenesis--especially in cutaneous veins.

Venous malformations with glomus cells are localised cutaneous lesions of vascular dysmorphogenesis. They are usually sporadic, but sometimes familial. Using five families, we mapped the locus, VMGLOM, to chromosome 1p21-p22. In order to refine this locus, spanning 4-6 Mbp, we then studied seven additional families. They exhibited linkage to VMGLOM and the combined lod score for all 12 families was 18.41 at theta = 0.0 for marker D1S188. We found a distinct haplotype shared by seven families, comprising seven alleles which are rare in the general population (P < 0.01). This indicates that the haplotype is identical by descent in all seven families, and hence the locus can be refined by inferring ancestral crossovers. Using this approach, we position the causative gene between two markers on the same non-chimeric YAC of 1.48 Mbp, a feasible size for positional cloning. As there is no known gene involved in vasculogenesis and/or angiogenesis in this YAC, the identification of the causative gene is likely to reveal a novel regulator or vascular development.

Vascular anomalies are congenital lesions that usually occur sporadically, but can be inherited. Previously, we have described that venous malformations, localized bluish-purple skin lesions, are caused by an activating mutation in the TIE2/TEK receptor. Moreover, we mapped another locus to chromosome 1p21-p22, for venous malformations with glomus cells (VM-GLOM). Here we report a physical map, based on 18 overlapping YAC clones, spanning this 5-Mb VMGLOM locus, from marker GATA63C06 to D1S2664. In addition, we report a sequence-ready PAC map of 46 clones covering 1.48 Mb within the YAC contig, a region to which we have restricted VMGLOM. We describe 21 new STSs and nine novel CA repeats, seven of which are polymorphic. These data will enable positional cloning of genes for diseases mapped to this locus, including the VMGLOM gene, likely a currently unknown regulator of vasculogenesis and/or angiogenesis.

Venous malformations (VMs) are localized defects of vascular morphogenesis. They can occur in every organ system, most commonly in skin and muscle. They can cause pain and bleeding, and in some critical locations they can be life threatening. Usually venous anomalies occur sporadically, but families with dominant inheritance have been identified. Using linkage analysis, we have established in earlier reports that some families with inherited VMs show linkage to chromosome 9p21; the mutation causes ligand-independent activation of an endothelial cell-specific receptor tyrosine kinase, TIE-2. Here we show that VMs with glomus cells (known as "glomangiomas"), inherited as an autosomal dominant trait in five families, are not linked to 9p21 but, instead, link to a new locus, on 1p21-p22, called "VMGLOM" (LOD score 12.70 at recombination fraction.00). We exclude three known positional candidate genes, DR1 (depressor of transcription 1), TGFBR3 (transforming growth factor-beta receptor, type 3), and TFA (tissue factor). We hypothesize that cutaneous venous anomalies (i.e., glomangiomas) are caused by mutations in a novel gene that may act to regulate angiogenesis, in concert with the TIE-2 signaling pathway.