International guidelines for the diagnosis and management of hereditary haemorrhagic telangiectasia.

BACKGROUND: HHT is an autosomal dominant disease with an estimated prevalence of at least 1/5000 which can frequently be complicated by the presence of clinically significant arteriovenous malformations in the brain, lung, gastrointestinal tract and liver. HHT is under-diagnosed and families may be unaware of the available screening and treatment, leading to unnecessary stroke and life-threatening hemorrhage in children and adults. OBJECTIVE: The goal of this international HHT guidelines process was to develop evidence-informed consensus guidelines regarding the diagnosis of HHT and the prevention of HHT-related complications and treatment of symptomatic disease. METHODS: The overall guidelines process was developed using the AGREE framework, using a systematic search strategy and literature retrieval with incorporation of expert evidence in a structured consensus process where published literature was lacking. The Guidelines Working Group included experts (clinical and genetic) from eleven countries, in all aspects of HHT, guidelines methodologists, health care workers, health care administrators, HHT clinic staff, medical trainees, patient advocacy representatives and patients with HHT. The Working Group determined clinically relevant questions during the pre-conference process. The literature search was conducted using the OVID MEDLINE database, from 1966 to October 2006. The Working Group subsequently convened at the Guidelines Conference to partake in a structured consensus process using the evidence tables generated from the systematic searches. RESULTS: The outcome of the conference was the generation of 33 recommendations for the diagnosis and management of HHT, with at least 80% agreement amongst the expert panel for 30 of the 33 recommendations.

Hereditary hemorrhagic telangiectasia: from molecular biology to patient care.

SUMMARY: Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular disorder characterized by severe and recurrent nosebleeds, mucocutaneous telangiectases, and, in some cases, life-threatening visceral arteriovenous malformations of various types, including pulmonary, hepatic, cerebral, and spinal. Gastrointestinal telangiectases are frequent and may cause severe bleeding. HHT type 1 results from mutations in ENG on chromosome 9 (coding for endoglin), and HHT type 2 results from mutations in ACVRL1 on chromosome 12 (coding for activin receptor-like kinase 1). Mutations of either of these two genes account for most clinical cases. In addition, mutations in MADH4 (encoding SMAD4), which cause a juvenile polyposis/HHT overlap syndrome, have been described, and recently, an HHT3 locus on chromosome 5 (5q31.3-5q32) has been reported. The mutated genes in HHT encode proteins that modulate transforming growth factor-beta superfamily signaling in vascular endothelial cells. Management of patients has changed considerably in the last 20 years, in terms of both treatment and the prevention of complications. The goal of this review was to describe the underlying molecular and cellular physiopathology, explore clinical and genetic diagnostic strategies for HHT, and present clinical management recommendations in order to treat symptomatic disease and to screen for vascular malformations.

Contribution of molecular analyses in diagnosing Marfan syndrome and type I fibrillinopathies: an international study of 1009 probands.

BACKGROUND: The diagnosis of Marfan syndrome (MFS) is usually initially based on clinical criteria according to the number of major and minor systems affected following international nosology. The number of FBN1 mutation carriers, at risk of aortic complications who would not be properly diagnosed based only on clinical grounds, is of growing importance owing to the increased availability of molecular screening. The aim of the study was to identify patients who should be considered for FBN1 mutation screening. METHODS: Our international series included 1009 probands with a known FBN1 mutation. Patients were classified as either fulfilling or not fulfilling "clinical" criteria. In patients with unfulfilled "clinical" criteria, we evaluated the percentage of additional patients who became positive for international criteria when the FBN1 mutation was considered. The aortic risk was evaluated and compared in patients fulfilling or not fulfilling the "clinical" international criteria. RESULTS: Diagnosis of MFS was possible on clinical grounds in 79% of the adults, whereas 90% fulfilled the international criteria when including the FBN1 mutation. Corresponding figures for children were 56% and 85%, respectively. Aortic dilatation occurred later in adults with unfulfilled "clinical criteria" when compared to the Marfan syndrome group (44% vs 73% at 40 years, p<0.001), but the lifelong risk for ascending aortic dissection or surgery was not significantly different in both groups. CONCLUSIONS: Because of its implications for aortic follow-up, FBN1 molecular analysis is recommended in newly suspected MFS when two systems are involved with at least one major system affected. This is of utmost importance in patients without aortic dilatation and in children.

Effect of mutation type and location on clinical outcome in 1,013 probands with Marfan syndrome or related phenotypes and FBN1 mutations: an international study.

Mutations in the fibrillin-1 (FBN1) gene cause Marfan syndrome (MFS) and have been associated with a wide range of overlapping phenotypes. Clinical care is complicated by variable age at onset and the wide range of severity of aortic features. The factors that modulate phenotypical severity, both among and within families, remain to be determined. The availability of international FBN1 mutation Universal Mutation Database (UMD-FBN1) has allowed us to perform the largest collaborative study ever reported, to investigate the correlation between the FBN1 genotype and the nature and severity of the clinical phenotype. A range of qualitative and quantitative clinical parameters (skeletal, cardiovascular, ophthalmologic, skin, pulmonary, and dural) was compared for different classes of mutation (types and locations) in 1,013 probands with a pathogenic FBN1 mutation. A higher probability of ectopia lentis was found for patients with a missense mutation substituting or producing a cysteine, when compared with other missense mutations. Patients with an FBN1 premature termination codon had a more severe skeletal and skin phenotype than did patients with an inframe mutation. Mutations in exons 24-32 were associated with a more severe and complete phenotype, including younger age at diagnosis of type I fibrillinopathy and higher probability of developing ectopia lentis, ascending aortic dilatation, aortic surgery, mitral valve abnormalities, scoliosis, and shorter survival; the majority of these results were replicated even when cases of neonatal MFS were excluded. These correlations, found between different mutation types and clinical manifestations, might be explained by different underlying genetic mechanisms (dominant negative versus haploinsufficiency) and by consideration of the two main physiological functions of fibrillin-1 (structural versus mediator of TGF beta signalling). Exon 24-32 mutations define a high-risk group for cardiac manifestations associated with severe prognosis at all ages.

[Establishing a new severity score for EEC: ectrodactyly-ectodermal dysplasia-cleft lip and palate]. / Etablissement d'un nouveau score de gravité dans le syndrome E.E.C.: ectodermal dysplasia-cleft lip and palate.

BACKGROUND: EEC (ectodactyly-ectodermal dysplasia-cleft lip and palate) is a rare disease transmitted by autosomal dominant inheritance with variable penetrance and weak expressivity. Clinical expression is thus very variable. Besides the three signs defining the syndrome, other manifestations include anomalous lacrimal ducts, urogenital malformations, transmission deafness, facial dysmorphism, and mental retardation. In 1995, Roelfsema and Cobben established a severity score on the basis of data in the literature. MATERIAL AND METHODS: We analyzed retrospectively the cases of 5 patients followed from 1980 to 2000 in two University Hospitals in France. Malformations were detailed and the Roelfsema and Cobben score was calculated. The real degree of disability was estimated from social activity level. We searched for a correlation between the Roelfsema and Cobben score and the real degree of disability. RESULTS: Our findings showed a poor correlation between disability and the Roelfsema and Cobben score. We proposed a new score which takes into account social disability. DISCUSSION: Our study revealed that the Roelfsema and Cobben score overly emphasizes anatomic malformations without taking into account natural adaptation to the social environment. Inversely, the Roelfsema and Cobben score gives little importance to invisible anomalies despite their invalidating effect.

Phenotype variability of two FAP families with an identical APC germline mutation at codon 1465: a potential modifier effect?

We report the cases of two familial adenomatous polyposis (FAP) families who presented with the same 2 base pair deletion (AG) at codon 1465 of the adenomatous polyposis coli (APC) gene, but showed phenotypic variability. The mutation was revealed by a simple nonradioactive method using a heteroduplex analysis and identified by a sequence analysis. This observation suggests the responsibility of modifier genes in FAP patients' phenotype.

Lissencephaly type III, stippled epiphyses and loose, thick skin: a new recessively inherited syndrome.

We report on two new cases of syndromic lissencephaly in two consanguineous sibs, with skeletal abnormality, born to young, healthy, second cousin parents with healthy children. In Case 1, fetal ultrasound screening at 32 weeks of gestation showed microcephaly, skin infiltration and equinovarus feet. MRI disclosed cerebral agyria, hypoplastic cerebral mantle and posterior agenesis of the corpus callosum. The propositus, a boy, died soon after birth at term. In Case 2, fetal ultrasound study performed at 16 weeks of gestation disclosed skin infiltration. MRI at 22 weeks of gestation showed microcephaly with agenesis of corpus callosum and cerebellar hypoplasia. Pregnancy was terminated at 22 weeks of gestation. The fetus had normal 46, XY karyotype and similar anomalies found in the index case, with cranio-facial edema and arthrogryposis. X-ray films showed epiphyseal stippling of cervical vertebrae, feet and sacrum. Metacarpal bones were shortened with hypoplastic distal phalanges. Neuropathological findings were concordant with the pattern described in type III lissencephaly: an agyric brain with hypoplastic brain stem and cerebellum, severe neuronal loss of the cortical plate, matrix zone, basal ganglia, brainstem nuclei and spinal cord with axonal swelling and microcalcification. This entity seems to be a new syndromic lissencephaly type III, because of epiphyseal calcifications and metacarpophalangeal bone dysplasia.

Mutation in the zonadhesin-like domain of alpha-tectorin associated with autosomal dominant non-syndromic hearing loss.

A gene responsible for autosomal dominant non-syndromic hearing impairment in two families (DFNA8 and DFNA12) has recently been identified as TECTA encoding alpha-tectorin, a major component of the tectorial membrane. In these families, missense mutations within the zona pellucida domain of alpha-tectorin were associated with stable severe mid-frequency hearing loss. The present study reports linkage to DFNA12 in a new family with autosomal dominant high frequency hearing loss progressing from mild to moderate severity. The candidate region refined to 3.8 cM still contained the TECTA gene. A missense mutation (C1619S) was identified in the zonadhesin-like domain. This mutation abolishes the first of the vicinal cysteines (1619Cys-Gly-Leu- 1622Cys) present in the D4 von Willebrand factor (vWf) type D repeat. These results further support the involvement of TECTA mutations in autosomal dominant hearing impairment, and suggest that vicinal cysteines are involved in tectorial membrane matrix assembly.

Non-C282Y familial iron overload: evidence for locus heterogeneity in haemochromatosis.

Haemochromatosis (HC) is an autosomal recessive disease with progressive iron overload leading to midlife onset of clinical complications. The causal gene (HFE) maps to 6p, in close linkage with the HLA class I genes. An HFE candidate gene recently identified has two missense mutations (C282Y and H63D) associated with the disease. Here we document the phenotypic and genetic analysis of a nuclear family comprising two sibs with symptomatic and massive iron overload before the age of 25. The disease seemed to be recessively transmitted and fitted the agreed criteria for haemochromatosis, but was neither associated with the C282Y and H63D mutations nor linked with HLA markers. Our data strongly support locus heterogeneity in haemochromatosis by showing evidence that the gene responsible for juvenile haemochromatosis (JH) does not map to 6p. In the absence of clear cut phenotypic distinction from typical haemochromatosis, patients below 30 years of age and C282Y negative should be considered as putative juvenile cases. This has practical implications in genetic counselling and family management.

An extension of the admixture test for the study of genetic heterogeneity in hereditary multiple exostoses.

Hereditary multiple exostoses (EXT) is an autosomal dominant disorder characterized by the presence of multiple cartilage-capped exostoses in the juxta-epiphyseal regions of the long bones. EXT is heterogeneous with at least three different locations currently having been identified on chromosomes 8, 11 and 19. We have tested a series of 29 EXT families for possible linkage to the three disease loci and estimated the probability of linkage of the disease to each locus in our series, by using an extension of the admixture test, which makes modelling of heterogeneous monogenic disease feasible. The maximum likelihood was obtained for proportions of 44%, 28% and 28% of families being linked to chromosome 8, 11 and 19, respectively. The a posteriori probability of linkage of the disease to EXT1, EXT2 and EXT3 was greater than 80% for 8/29, 5/29 and 3/29 families, respectively, and did not give evidence of a fourth locus for the disease. The present approach can be generalized to the investigation of genetic heterogeneity in other monogenic diseases, as it simultaneously estimates the location of each disease gene and the proportion of families linked to each locus.

[Neurosarcoma associated with neurofibromatosis 1. Apropos of a case and review of the literature]. / Neurosarcome associé à une neurofibromatose de type 1. A propos d'un cas et revue de la littérature.

BACKGROUND: Type 1 neurofibromatosis considerably increases the risk of cancer development, particularly neurosarcoma. We report a case in a patient with chemosensitive metastatic neurosarcoma. CASE REPORT: A young female patient with familial type 1 neurofibromatosis developed pleural metastasis of a neurosarcoma located on the arm. This tumor was initially highly sensitive to chemotherapy, but relapse occurred. DISCUSSION: Follow-up in the order members of the family was particularly difficult to organize. One sister developed cerebral astrocytoma. Neurosarcomas develop earlier in patients with type 1 neurofibromatosis, worsening prognosis. We suggest a prospective and structured registration of such cases using a network of clinicians and pathologists in order to improve management schemes.

[Spontaneous colonic perforations revealing Ehlers-Danlos syndrome type IV]. / Perforations coliques spontanées révélatrices d'un syndrome d'Ehlers-Danlos de type IV.

BACKGROUND: The malignant form of Ehlers-Danlos syndrome type IV owes its bad reputation to a proneness to spontaneous rupture of bowel or large vessels, which may reveal the disease. CASE REPORT: A girl suffered acute rupture of the sigmoid at the age of 5 years and rupture of the left colon, twice, at the age of 11 and 13 years, respectively. These ruptures required colostomy and finally colectomy. A proneness to bruisability, history of dislocation of hips, hypermobile joints, ovarian cysts and some minor abnormalities of her face resembled that of the Ehlers-Danlos syndrome which was confirmed by optic and electronic microscopy of the skin biopsy. CONCLUSION: This is the youngest case of rupture of bowel reported in Ehlers-Danlos syndrome. Long-term prognosis is influenced by repetition of intestinal ruptures and occurrence of vascular complications.

A third locus for hereditary haemorrhagic telangiectasia maps to chromosome 12q.

Hereditary haemorrhagic telangiectasia (HHT) or Rendu-Osler-Weber disease is an autosomal dominant vascular disorder which associates epistaxis, mucocutaneous and visceral telangiectases, and recurrent haemorrhage with chronic anaemia and visceral shuntings. Recently, the tumour growth factor (TGF)-beta binding protein endoglin localized to 9q33-34 was identified as responsible for HHT in several large kindreds with pulmonary arteriovenous malformations (PAVMs). Additional linkage studies demonstrated that HHT is a genetically heterogeneous disorder with families unlinked to this region of 9q. In the families in which HHT was not linked to chromosome 9, less PAVMs were present. Furthermore, in one of these families, HHT was found linked to 3p22, where the TGF-beta II receptor is located. In this linkage study, we have analysed DNA from two families, in which HHT was unlinked to chromosome 9q and 3p, and PAVMs were absent, with a series of genetic markers on the centromeric region of chromosome 12. Using two-point linkage analysis, a significant lod score of Zmax = 7.86 at theta = 0.05 was obtained with the D12S85 microsatellite marker.

[Early manifestations of Tangier disease]. / Les manifestations précoces de la maladie de Tangier.

BACKGROUND: The diagnosis of Tangier disease in childhood is based on the specific aspect of tonsils or by screening relatives of affected subjects. CASE REPORT: A moderately enlarged liver associated with splenomegaly was found upon routine physical examination of a 3 month-old breast-fed boy, born in Turkey from consanguineous parents. Laboratory studies disclosed moderate increase in serum alanine aminotransferase activity (ALAT 52 UI/l, N < 30). The diagnosis of Tangier disease was confirmed by studies of plasma cholesterol and apolipoprotein A. By 8 months of age, the patient had enlarged orange tonsils. Small cervical, axillary and inguinal lymphadenopathies were present. The tonsilar and adenoidal tissues were removed at 18 months of age because the patient suffered from chronic airway obstruction. Colonoscopic examination revealed tiny flat orange spots, 1 to 2 mm in diameter, scattered throughout the rectosigmoidal and colonic mucosa. Survey of the family led to the discovery of one sister, with asymptomatic apolipoprotein Al deficiency and a normal sister, while the parents were heterozygotes for Tangier disease. CONCLUSION: Enlarged liver associated with a moderate level in serum aminotransferase may be an early manifestation of Tangier disease in infants. Rectosigmoidal and colonic lesions may be convenient for biopsy when tonsillectomy is not indicated.

Pheochromocytoma as the first manifestation of von Hippel-Lindau disease.

BACKGROUND: von Hippel-Lindau disease is an autosomal dominant disorder characterized by the development of hemangioblastomas in the cerebellum, spinal cord, and retina, renal cell carcinoma and cysts, pancreatic cysts, and pheochromocytoma. METHODS: We have studied a series of 36 French patients affected with von Hippel-Lindau disease pheochromocytoma. Thirty (83%) of them were diagnosed as having von Hippel-Lindau disease because the disease occurred in a familial von Hippel-Lindau disease setting; six (17%) were diagnosed as having von Hippel-Lindau disease because they displayed another characteristic manifestation of that disease. RESULTS: The mean age at pheochromocytoma diagnosis was 29 +/- 14 years (5 to 62 years). Bilateral tumors were documented in 15 (42%) cases, paraganglioma was associated with adrenal pheochromocytoma in four cases, and malignant pheochromocytoma occurred in three cases. Prevalence of pheochromocytoma revealing von Hippel-Lindau disease was 20 (53%) out of 36. In six cases pheochromocytoma was the only manifestation of the disease. CONCLUSIONS: In the interest of the patients themselves and of family members who are at risk, search for von Hippel-Lindau disease must be systematic in the presence of pheochromocytoma. Basic checkup may be completed with familial inquiry, ophthalmoscopy, cerebral magnetic resonance imaging, abdominal ultrasonography, and computed tomography-scan for detection of latent lesions. In the future, after characterization of von Hippel-Lindau disease gene mutations, molecular diagnosis is going to be possible in individual patients.

A gene for hereditary multiple exostoses maps to chromosome 19p.

Hereditary multiple exostoses (EXT) is an autosomal dominant bony disorder characterized by the formation of cartilage-capped juxta-epiphyseal prominences on the long bones. Recently, a disease gene (EXT 1) has been mapped to chromosome 8q23-q24 by linkage analysis in informative families. Here, we report on the genetic mapping of a second locus (EXT 2) to the short arm of chromosome 19 by linkage to a microsatellite DNA marker at the D19S221 locus, which gives additional support to the view that EXT is a genetically heterogeneous condition.