Genotype-phenotype correlations in von Hippel-Lindau disease

von Hippel-Lindau (VHL) disease is a dominantly inherited familial cancer syndrome resulting from mutations in the VHL tumor suppressor gene. VHL disease displays marked variation in expression and the presence of pheochromocytoma has been linked to missense VHL mutations. We analyzed genotype-phenotype correlations in 573 individuals with VHL disease. Routine clinical and radiological surveillance of VHL patients and at-risk relatives was associated with increased detection of retinal angiomatosis (73 vs. 59% of cases) and a reduction in age at diagnosis of renal cell carcinoma (RCC) (44.0+/-10.9 vs. 39.7+/-10.3 years). We confirmed the association of pheochromocytoma with missense mutations described previously, but stratifying missense mutations into those that resulted in substitution of a surface amino acid and those that disrupted structural integrity demonstrated that surface amino acid substitutions conferred a higher pheochromocytoma risk. Age at first manifestation of VHL disease was significantly earlier (P=0.001), and age-related risks of retinal angiomas and RCC were higher (P=0.022 and P=0.0008, respectively) in individuals with a nonsense or frameshift mutation than in those with deletions or missense mutations that disrupted the structural integrity of the VHL gene product (pVHL). These results extend genotype-phenotype-protein structure correlations in VHL disease and provide a baseline for future chemoprevention studies in VHL disease.     

Genotype-phenotype correlations of pheochromocytoma in two large von Hippel-Lindau (VHL) type 2A kindreds with different missense mutations

Von Hippel–Lindau (VHL) disease type 2A is an inherited tumor syndrome characterized by predisposition to pheochromocytoma (pheo), retinal hemangioma (RA), and central nervous system hemangioblastoma (HB). Specific VHL subtypes display genotype–phenotype correlations but, unlike other familial syndromes such as MEN‐2, the phenotype in VHL has not yet been stratified at the codon level. Over decades, we have managed two very large VHL type 2A regional kindreds with nearly adjacent but distinct VHL missense mutations. We determined the phenotype of Family 2 and compared the clinical and pathologic parameters of pheo between 30 members of Family 1 (Y112H mutation) and 33 members of Family 2 (Y98H mutation) with mean follow‐up of 15.5 and 12.1 years, respectively (P = 0.24). In Family 2, pheo was the most frequent VHL manifestation (79%) and all pheo diagnoses occurred by age 50. Age at first diagnosis was younger in Family 2 than in Family 1 (mean 19.7 vs. 28.8 years; P = 0.02). Pheo expressivity differed by genotype: Family 1 pheo was more likely to be multifocal (P = 0.04), as well as malignant (P < 0.01) and lethal (P = 0.02). Family 1 pheo was also more likely to secrete vanillylmandelic acid (VMA) alone (P = 0.05). This analysis of 130 pheochromocytomas in 63 VHL type 2A patients demonstrates that mutation‐specific malignancy and expression patterns exist within the VHL type 2A subtype, and provides information that may help tailor the screening and management algorithms of affected members and those at risk. © 2010 Wiley‐Liss, Inc.     

Loss of the actin regulator HSPC300 results in clear cell renal cell carcinoma protection in Von Hippel-Lindau patients

Clear cell renal cell carcinoma (ccRCC) is the most common malignant neoplasm of the kidney. The majority of hereditary and sporadic ccRCC cases are associated with germline and somatic mutations in the Von Hippel-Lindau gene (VHL), respectively. Gross deletions at the VHL locus can result either in ccRCC or in a mild clinical phenotype, with the absence of ccRCC development. Our goal in this study was to identify the molecular basis responsible for these differences in the clinical behavior in order to predict patients' phenotype. Using multiplex ligation-dependent amplification (MLPA), we identified and characterized gross VHL deletions in Spanish VHL families. A candidate gene related to this clinical association, HSPC300, was identified and depleted by RNA interference. It was possible to narrow the susceptibility region related to the mild clinical phenotype down to approximately 14 kb that included HSPC300 (C3orf10), a regulator of actin dynamics and cytoskeleton organization. Whereas 9 out of 10 families with ccRCC retained HSPC300 in the germline, loss of the HSPC300 locus was associated with mild clinical presentation of the disease in 6 out of 8 families. In fact, genetic depletion of HSPC300 resulted in cytoskeleton abnormalities and cytokinesis arrest in several tumor cell lines including ccRCC cells, suggesting that tumor cell proliferation was compromised in the absence of HSPC300. These clinical and functional data indicate a relevant function of HSPC300 in tumor cell progression, and suggest future therapeutic strategies based upon the inhibition of HSPC300 in renal cell carcinoma and possibly on other cancers.     

中国人von Hippel-Lindau综合征种系突变研究

目的探讨中国人von Hippel-Lindau综合征（VHL）种系突变的特点及其临床应用价值。方法分析6个VHL家系的临床资料，采用聚合酶链反应和扩增产物直接测序的方法对其中的21位成员进行VHL基因种系突变研究。结果在6个家系中，5个Ⅰ型家系，1个ⅡA型家系。6种不同的VHL基因种系突变被确定，其中包括错义突变4个，无义突变1个，缺失突变1个。4个分布在第1外显子、1个在第2外显子和1个在第3外显子。21人接受基因检测的个体中，14人存在VHL基因种系突变，其中包括10例均符合VH临床诊断标准的患者、1例疑似VHL患者和3例致病基因携带者。结论中国汉族人VHL患者存在基因种系突变且第1外显子的后1／3可能为主要的突变区域；VHL基因种系突变检测在疾病诊断和早期发现无症状患者及致病基因携带者方面具有重要作用。     

Genetic characterization and structural analysis of VHL Spanish families to define genotype-phenotype correlations

Von Hippel-Lindau (VHL) disease is a hereditary cancer syndrome caused by germline mutations in the VHL gene. This gene, located in the 3p25-26 chromosome, is a tumor suppressor gene associated with the inhibition of angiogenesis and apoptosis, cell cycle exit, fibronectin matrix assembly, and proteolysis. To define the molecular basis of VHL in a Spanish population, we studied 33 patients suspected of suffering familial or de novo VHL disease and two familial pheochromocytoma cases. Sequence analysis of the coding regions of the VHL gene revealed germline sequence variants in 68.7% (24 out of 35) of the patients, and four of them presented with undescribed germline alterations: g.5429-5430insG, p.Leu128Arg, p.Tyr175Cys, and p.Tyr175Asn. For the remaining 11 patients who showed negative for point mutations, we performed Southern blot analysis and detected gross rearrangements in eight cases (22.8% of the index cases). Our results support the relevance of VHL gene analysis in familial pheochromocytoma cases and also in those with no familial history. In order to investigate the relevance of different amino acid changes in the VHL phenotype, we also analyzed the genotype-phenotype correlations using structural analysis to assess protein stability and complexes. The association of clear cell renal carcinoma (CCRC) development with a relatively high loss of structural stability in pVHL missense-mutants was consistent. Structural stability data in the genotype-phenotype correlations therefore provides us with a better understanding of VHL clinical implications. It is also a suitable approach to the evaluation of unknown significance changes.     

PKHD1 mutations in families requesting prenatal diagnosis for autosomal recessive polycystic kidney disease (ARPKD)

Autosomal recessive polycystic kidney disease (ARPKD) is one of the most common hereditary renal cystic diseases in children. The clinical spectrum ranges from stillbirth and neonatal demise to survival into adulthood. In a given family, however, patients usually display comparable phenotypes. Many families who lost a child with severe ARPKD desire an early and reliable prenatal diagnosis (PD). Given the limitations of antenatal ultrasound, this is only feasible by molecular genetics that became possible in 1994 when PKHD1, the locus for ARPKD, was mapped to chromosome 6p. However, linkage analysis might prove difficult or even impossible in families with diagnostic doubts or in whom no DNA of an affected child is available. In such cases the recent identification of the PKHD1 gene provides the basis for direct mutation testing. However, due to the large size of the gene, lack of knowledge of the encoded protein's functional properties, and the complicated pattern of splicing, significant challenges are posed by PKHD1 mutation analysis. Thus, it is important to delineate the mutational spectrum and the reachable mutation detection rate among the cohort of severely affected ARPKD patients. In the present study, we performed PKHD1 mutation screening by DHPLC in a series of 40 apparently unrelated families with at least one peri- or neonatally deceased child. We observed 68 out of an expected 80 mutations, corresponding to a detection rate of 85%. Among the mutations identified, 23 were not reported previously. We disclosed two underlying mutations in 29 families and one in 10 cases. Thus, in all but one family (98 percent;), we were able to identify at least one mutation substantiating the diagnosis of ARPKD. Approximately two-thirds of the changes were predicted to truncate the protein. Missense mutations detected were nonconservative, with all but one of the affected amino acid residues found to be conserved in the murine ortholog. PKHD1 mutation analysis has proven to be an efficient and effective means to establish the diagnosis of ARPKD.     

Cystathionine beta-synthase deficiency in Georgia (USA): correlation of clinical and biochemical phenotype with genotype

Cystathionine beta-synthase (CBS) deficiency is a rare autosomal recessive disorder that is the most frequent cause of clinical homocystinuria. Patients not treated in infancy have multi-systems disorders including dislocated lenses, mental deficiency, osteoporosis, premature arteriosclerosis, and thrombosis. In this paper, we examine the relationship of the clinical and biochemical phenotypes with the genotypes of 12 CBS deficient patients from 11 families from the state of Georgia, USA. By DNA sequencing of all of the coding exons we identified mutations in the CBS genes in 21 of the 22 possible mutant alleles. Ten different missense mutations were identified and one novel splice-site mutation was found. Five of the missense mutations were previously described (G307S, I278T, V320A, T353M, and L101P), while five were novel (A226T, N228S, A231L, D376N, Q526K). Each missense mutation was tested for function by expression in S. cerevisiae and all were found to cause decreased growth rate and to have significantly decreased levels of CBS enzyme activity. The I278T and T353M mutations accounted for 45% of the mutant alleles in this patient cohort. The T353M mutation, found exclusively in four African American patients, was associated with a B(6)-nonresponsive phenotype and detection by newborn screening for hypermethioninemia. The I278T mutation was found exclusively in Caucasian patients and was associated with a B(6)-responsive phenotype. We conclude that these two mutations occurred after ethnic socialization and that the CBS genotype is predictive of phenotype.     

Genotype-phenotype correlation of 5p- syndrome: pitfall of diagnosis

To clarify the genotype–phenotype correlation of 5p- syndrome, FISH analyses were performed for six patients by using a series of probes spanning 5p13.1–p15.33. Genotypically, break points of deletion were quite different. Three of the six patients were diagnosed as interstitial deletion on chromosome 5p by G-banding method and FISH analysis; however, all of them proved to be entire distal deletions of 5p caused by unbalanced chromosomal translocations. Furthermore, one 5p- syndrome patient was diagnosed only by the FISH analysis using a single probe but not by ordinary chromosomal analyses. Therefore, when ordinary chromosomal analysis cannot detect any deletion in a patient who is phenotypically suspected of 5p- syndrome, multiple FISH analysis or parental chromosomal analysis would be needed for correct diagnosis. Interestingly, one patient with terminal deletion between 5p15.31-pter lacks mental retardation and cat-like crying, indicating that this region might not be responsible for those cardinal features of 5p- syndrome. Further studies on genotype–phenotype correlation will help us better understand 5p- syndrome and also determine functional mapping of the 5p region.     

Germline mutation profile of the VHL gene in von Hippel-Lindau disease and in sporadic hemangioblastoma

Von Hippel-Lindau (VHL) disease is a dominantly inherited disorder predisposing those afflicted to hemangioblastomas of the central nervous system and the retina, renal cell carcinomas, pheochromocytomas, and pancreatic tumors. The disease has been associated with mutations of the VHL gene. The screening of 92 unrelated patients with VHL disease for point mutations in this gene revealed 61 DNA variants. In addition, a search for EcoR1 rearrangements revealed germline anomalies in 5 patients. The 61 variants could be subdivided in 20 mutations predicted to alter the open reading frame (8 nonsense mutations, 8 frame shift mutations, and 4 mutations in consensus splicing sites) and 43 DNA sequence variants of a priori unknown biological consequence (4 in-frame insertions or deletions, 36 missense mutations, and 3 apparently silent variations). The 3′ end of the coding sequence of the VHL gene, which encodes the Elongin binding domain was the site of 5 of 20 truncating mutations (25%) and of 18 of 41 DNA variants (44%) causing uncertain functional impairment. A similar screening in 18 patients with sporadic hemangioblastoma revealed 2 missense DNA variants. In order to corroborate this latter observation, a systematic screening for germline alteration of the VHL gene might be performed in a larger series of sporadic hemangioblastoma. If this preliminary result is confirmed, more than 10% of sporadic hemangioblastoma might be related to a mild VHL disease, thus a follow-up program similar to that recommended in cases of VHL disease should probably be discussed in the corresponding families. Hum Mutat 12:424–430, 1998. © 1998 Wiley-Liss, Inc.     

Detection of a novel germline mutation in the von Hippel-Lindau tumour-suppressor gene by fluorescence-labelled base excision sequence scanning (F-BESS)

The von Hippel Lindau (VHL) syndrome is an inherited multi-tumour disorder characterised by clinical heterogeneity and high penetrance. The VHL gene has been shown to be a tumour-suppressor gene. A carrier of a germline mutation will be predisposed to a high variety of benign and malign tumours affecting different organ systems. As treatment of VHL malformations in presymptomatic stages will improve significantly the clinical outcome and the patient's quality of life, early and unambiguous detection of a germline mutation is mandatory. Direct sequencing especially of large genes might be laborious and time consuming. Therefore, most laboratories apply single strand conformational polymorphism (SSCP) analysis as an initial screening technique. Major disadvantages of this approach are the requirement of specialised equipment and a limited detection rate of about 70%. To overcome these problems, we applied the modified technique of fluorescence-labelled base excision sequence scanning (F-BESS). A young patient without family history of VHL with two hemangioblastoma of the cerebellum, pancreatic cysts and angiomatosis retinae was presented. Applying F-BESS, we detected a frameshift in exon 2 as a de novo germline mutation. Direct sequencing revealed an insertion of C at position 631/632. This is a novel VHL mutation, which results in truncation of the VHL protein omitting the Elongin-binding domain. Applying SSCP on the same DNA, no alteration could be detected. Three further family members were tested negative for the mutation by F-BESS in accordance with lack of any clinical VHL features. As F-BESS appears to be a reliable, fast and unexpensive method, we recommend this technique as an initial screening method.     

Mosaicism in von Hippel–Lindau disease with severe renal manifestations

von Hippel–Lindau (VHL) disease is an inheritable multisystem tumor syndrome characterized by multiple benign and malignant tumors affecting multiple organs. VHL is the result of a germline mutation in the VHL tumor suppressor gene. Molecular genomic analysis routinely confirms the clinical diagnosis. However, the use of molecular diagnostic methods can often be insufficient for the detection of mosaic germline VHL mutations, making the diagnosis of some cases of VHL difficult. Here, we report the case of a VHL mosaic patient with bilateral renal lesions in the absence of other VHL‐associated lesions. A VHL mutation was not originally detected by routine molecular testing. Nonetheless, the detection of a heterozygous c.194C>G (p.Ser65Trp) VHL mutation in the patient's daughter prompted further genetic assessment and eventually resulted in the finding of a mosaic c.194C>G (p.Ser65Trp) VHL mutation in the patient. The mutation rate was 18.8 ± 3.84% in peripheral leukocytes. As the frequency of VHL mosaicism remains underdetermined, the possibility of a diagnosis of mosaic VHL should be considered in patients with both typical and atypical VHL‐associated manifestations.     

中国人von Hippel-Lindau病家系致病基因大片段缺失研究

目的 研究中国人von Hippel-Lindau病(von Hippel-Lindau syndrome,VHL)家系致病基因大片段缺失情况及其表型特点.方法 采用通用引物荧光定量PCR(universal primer quantitative fluorescent multiplex-polymerase chain reaction,UPQFM-PCR)技术结合GeneSean分析系统对新发现的20个VHL病家系的先证者及部分自愿者进行VHL基因胚系突变大片段缺失检测.结果 20例先证者中检测到VHL基因大片段缺失6例,其中第1外显子缺失3例、第3外显子缺失1例、VHL基因完全缺失2例.进一步检测其中2个家系其他患者和部分成员也存在与先证者相同的VHL基因缺失.2个VHL基因完全缺失的家系,其患者表现为中枢神经系统血管母细胞瘤和视网膜血管瘤但无肾癌表型.结论 中国汉族人VHL患者基因种系突变存在VHL基因大片段缺失;VHL病诊断应常规开展VHL基因大片段缺失检测;VHL基因完全缺失和中枢系统血管母细胞瘤和视网膜血管瘤可能存在一定关系并需进一步研究.     

Phenotypic analysis of individuals with Costello syndrome due to HRAS p.G13C

Costello syndrome is characterized by severe failure-to-thrive, short stature, cardiac abnormalities (heart defects, tachyarrhythmia, and hypertrophic cardiomyopathy (HCM)), distinctive facial features, a predisposition to papillomata and malignant tumors, postnatal cerebellar overgrowth resulting in Chiari 1 malformation, and cognitive disabilities. De novo germline mutations in the proto-oncogene HRAS cause Costello syndrome. Most mutations affect the glycine residues in position 12 or 13, and more than 80% of patients share p.G12S. To test the hypothesis that subtle genotype-phenotype differences exist, we report the first cohort comparison between 12 Costello syndrome individuals with p.G13C and individuals with p.G12S. The individuals with p.G13C had many typical findings including polyhydramnios, failure-to-thrive, HCM, macrocephaly with posterior fossa crowding, and developmental delay. Subjectively, their facial features were less coarse. Statistically significant differences included the absence of multifocal atrial tachycardia (P-value = 0.033), ulnar deviation of the wrist (P < 0.001) and papillomata (P = 0.003), and fewer neurosurgical procedures (P = 0.024). Fewer individuals with p.G13C had short stature (height below -2 SD) without use of growth hormone (P < 0.001). The noteworthy absence of malignant tumors did not reach statistical significance. Novel ectodermal findings were noted in individuals with p.G13C, including loose anagen hair resulting in easily pluckable hair with a matted appearance, different from the tight curls typical for most Costello syndrome individuals. Unusually long eye lashes requiring trimming are a novel finding we termed dolichocilia. These distinctive ectodermal findings suggest a cell type specific effect of this particular mutation. Additional patients are needed to validate these findings.     

High throughput mutation screening of the factor VIII gene (F8C) in hemophilia A: 37 novel mutations and genotype-phenotype correlation

Hemophilia A (HEMA) is an X-linked bleeding disorder caused by mutations in the factor VIII gene (F8C). Molecular genetic testing for the factor VIII gene is challenging due to its large size. Here we present results of high throughput mutation scanning based on Southern blot analysis and direct sequencing of all PCR amplified coding exons and the exon-intron boundaries of the factor VIII gene. The results of mutation analysis on 89 hemophiliac males showed presence of a disease-causing mutation in 80 individuals (90%, 95% CI of 82%-95%). Seven out of nine mutation-negative individuals were severe cases of hemophilia A with < 1% factor VIII protein in the blood. The correlation of phenotype with genotype as observed in this study was not absolute. This finding is supported by similar observations in the international database for hemophilia A mutations (HAMSTeRS). This issue raises the importance of genotypes at other loci that can act as modifiers for the phenotype. Thirty-four novel mutations and three novel substitutions for previously reported amino acid residues were identified in this series of 80 mutations. The mutations cover the full spectrum including rearrangements, deletions, frameshift, and point mutations. The novel missense mutations require careful evaluation. Prediction of a mutation as the disease-causing allele was made from the nature of the substitution and the degree of conservation of the mutated amino acid among species that have diverged in evolution. In some cases segregation analysis of the mutation with disease condition was performed when other family members were available.     

Mapping structural landmarks, ligand binding sites, and missense mutations to the collagen IV heterotrimers predicts major functional domains, novel interactions, and variation in phenotypes in inherited diseases affecting basement membranes

Collagen IV is the major protein found in basement membranes. It comprises three heterotrimers (α1α1α2, α3α4α5, and α5α5α6) that form distinct networks, and are responsible for membrane strength and integrity.We constructed linear maps of the collagen IV heterotrimers ("interactomes") that indicated major structural landmarks, known and predicted ligand-binding sites, and missense mutations, in order to identify functional and disease-associated domains, potential interactions between ligands, and genotype–phenotype relationships. The maps documented more than 30 known ligand-binding sites as well as motifs for integrins, heparin, von Willebrand factor (VWF), decorin, and bone morphogenetic protein (BMP). They predicted functional domains for angiogenesis and haemostasis, and disease domains for autoimmunity, tumor growth and inhibition, infection, and glycation. Cooperative ligand interactions were indicated by binding site proximity, for example, between integrins, matrix metalloproteinases, and heparin. The maps indicated that mutations affecting major ligand-binding sites, for example, for Von Hippel Lindau (VHL) protein in the α1 chain or integrins in the α5 chain, resulted in distinctive phenotypes (Hereditary Angiopathy, Nephropathy, Aneurysms, and muscle Cramps [HANAC] syndrome, and early-onset Alport syndrome, respectively). These maps further our understanding of basement membrane biology and disease, and suggest novel membrane interactions, functions, and therapeutic targets.     

Congenital myasthenic syndromes: Achievements and limitations of phenotype-guided gene-after-gene sequencing in diagnostic practice: A study of 680 patients

Congenital myasthenic syndromes (CMSs) are clinically and genetically heterogeneous disorders characterized by a neuromuscular transmission defect. Even though CMSs are genetic disorders, they are highly treatable, and the appropriate drug treatment depends on the underlying genetic defect. This highlights the importance of genetic testing in CMS. In recent years, the molecular basis of CMS has constantly broadened and disease‐associated mutations have been identified in 14 genes encoding proteins of the neuromuscular junction. In the dawn of novel sequencing strategies, we report on our 14‐year experience in traditional Sanger‐based mutation screening of a large cohort of 680 independent patients with suspected CMS. In total, we identified disease‐causing mutations in 299 patients (44%) of patients in various known CMS genes, confirming the high degree of genetic heterogeneity associated with the disease. Apart from four known founder mutations, and a few additional recurrent mutations, the majority of variants are private, found in single families. The impact of previously reported genotype–phenotype correlations on efficiency of genetic testing was analyzed in our population. Taking our experiment into account, we present our algorithm for genetic testing in CMS. Hum Mutat 33:1474–1484, 2012. © 2012 Wiley Periodicals, Inc.     

Genotype–phenotype correlation in von Hippel‐Lindau families with renal lesions

The original article to which this Erratum refers was published in Human Mutation 24:215–224 Human Mutation(2004) 24(3) 215–224 In the published version of this article, the key to Figure 2 was omitted. Please find Figure 2 printed here in its entirety.     

VHL mutations and their correlation with tumour cell proliferation, microvessel density, and patient prognosis in clear cell renal cell carcinoma.

Mutations of the von Hippel-Lindau (VHL) gene are considered critical for the initiation of clear cell renal cell carcinoma. The VHL protein is involved in regulation of the cell cycle and neo-vascularization. In this study, the association of VHL mutations with tumour cell proliferation, angiogenesis, and clinical outcome was analysed in 113 clear cell renal cell carcinomas. The degree of angiogenesis and tumour cell proliferation was immunohistochemically determined by counting microvessels (microvessel density, anti-CD34 antibody) and cells with proliferating activity (Ki-67 labelling index, MIB-1 antibody). Forty-eight different VHL sequence alterations were found in 38 of 113 patients (34%) by direct sequencing. Nineteen VHL mutations were frameshifts and nonsense mutations, predicted to change the open reading frame of VHL. These 'loss-of-function' mutations correlated with worse prognosis in univariate analysis (p=0.02). Tumour grade, stage, microvessel density, and tumour cell proliferation were not associated with VHL alterations. These findings may indicate that 'loss-of-function' VHL mutations are involved in the progression of a clear cell renal cell carcinoma subset, whereas regulation of angiogenesis and proliferation of renal carcinoma in vivo is apparently not directly influenced by VHL alterations.     

Genotype-phenotype correlation in von Hippel-Lindau disease: identification of a mutation associated with VHL type 2A.

A family with von Hippel-Lindau disease (VHL) type 2A has been shown to have a T to C missense mutation at nucleotide 547 of the VHL gene. This gives further support for the proposal to associate the 547 T to C mutation with phenotype VHL 2A.     

Arterial tortuosity syndrome: clinical and molecular findings in 12 newly identified families

Arterial tortuosity syndrome (ATS) is a rare autosomal recessive connective tissue disease, characterized by widespread arterial involvement with elongation, tortuosity, and aneurysms of the large and middle-sized arteries. Recently, SLC2A10 mutations were identified in this condition. This gene encodes the glucose transporter GLUT10 and was previously suggested as a candidate gene for diabetes mellitus type 2. A total of 12 newly identified ATS families with 16 affected individuals were clinically and molecularly characterized. In addition, extensive cardiovascular imaging and glucose tolerance tests were performed in both patients and heterozygous carriers. All 16 patients harbor biallelic SLC2A10 mutations of which nine are novel (six missense, three truncating mutations, including a large deletion). Haplotype analysis suggests founder effects for all five recurrent mutations. Remarkably, patients were significantly older than those previously reported in the literature (P=0.04). Only one affected relative died, most likely of an unrelated cause. Although the natural history of ATS in this series was less severe than previously reported, it does indicate a risk for ischemic events. Two patients initially presented with stroke, respectively at age 8 months and 23 years. Tortuosity of the aorta or large arteries was invariably present. Two adult probands (aged 23 and 35 years) had aortic root dilation, seven patients had localized arterial stenoses, and five had long stenotic stretches of the aorta. Heterozygous carriers did not show any vascular anomalies. Glucose metabolism was normal in six patients and eight heterozygous individuals of five families. As such, overt diabetes is not related to SLC2A10 mutations associated with ATS.