Whole-exome sequencing improves the diagnosis yield in sporadic infantile spasm syndrome.

Infantile spasms syndrome (ISs) is characterized by clinical spasms with ictal electrodecrement, usually occurring before the age of 1 year and frequently associated with cognitive impairment. Etiology is widely heterogeneous, the cause remaining elusive in 40% of patients. We searched for de novo mutations in 10 probands with ISs and their parents using whole-exome sequencing (WES). Patients had neither consanguinity nor family history of epilepsy. Common causes of ISs were excluded by brain magnetic resonance imaging (MRI), metabolic screening, array-comparative genomic hybridization (CGH) and testing for mutations in CDKL5, STXBP1, and for ARX duplications. We found a probably pathogenic mutation in four patients. Missense mutations in SCN2A (p.Leu1342Pro) and KCNQ2 (p.Ala306Thr) were found in two patients with no history of epilepsy before the onset of ISs. The p.Asn107Ser missense mutation of ALG13 had been previously reported in four females with ISs. The fourth mutation was an in-frame deletion (p.Phe110del) in NR2F1, a gene whose mutations cause intellectual disability, epilepsy, and optic atrophy. In addition, we found a possibly pathogenic variant in KIF3C that encodes a kinesin expressed during neural development. Our results confirm that WES improves significantly the diagnosis yield in patients with sporadic ISs.

Unraveling the intrafamilial correlations and heritability of tumor types in MEN1: a Groupe d'étude des Tumeurs Endocrines study.

BACKGROUND: MEN1, which is secondary to the mutation of the MEN1 gene, is a rare autosomal-dominant disease that predisposes mutation carriers to endocrine tumors. Most studies demonstrated the absence of direct genotype-phenotype correlations. The existence of a higher risk of death in the Groupe d'étude des Tumeurs Endocrines-cohort associated with a mutation in the JunD interacting domain suggests heterogeneity across families in disease expressivity. This study aims to assess the existence of modifying genetic factors by estimating the intrafamilial correlations and heritability of the six main tumor types in MEN1. METHODS: The study included 797 patients from 265 kindred and studied seven phenotypic criteria: parathyroid and pancreatic neuroendocrine tumors (NETs) and pituitary, adrenal, bronchial, and thymic (thNET) tumors and the presence of metastasis. Intrafamilial correlations and heritability estimates were calculated from family tree data using specific validated statistical analysis software. RESULTS: Intrafamilial correlations were significant and decreased along parental degrees distance for pituitary, adrenal and thNETs. The heritability of these three tumor types was consistently strong and significant with 64% (s.e.m.=0.13; P<0.001) for pituitary tumor, 65% (s.e.m.=0.21; P<0.001) for adrenal tumors, and 97% (s.e.m.=0.41; P=0.006) for thNETs. CONCLUSION: The present study shows the existence of modifying genetic factors for thymus, adrenal, and pituitary MEN1 tumor types. The identification of at-risk subgroups of individuals within cohorts is the first step toward personalization of care. Next generation sequencing on this subset of tumors will help identify the molecular basis of MEN1 variable genetic expressivity.

[Role of T lymphocyte cyclic nucleotides and G protein in sarcoidosis]. / Quels rôles les anomalies de la voie des nucléotides cycliques et des protéines G jouent-elles dans le désordre biochimique des lymphocytes T dans la sarcoïdose ?

CD4+ T lymphocytes play a major role in the pathophysiology of sarcoidosis. Many studies have investigated the immunological and genetic abnormalities in this disease. There are few studies concerning the metabolic pathways. Essentially they concern the pathways: STAT1, MAPK38, NF-κB, Galphai, cAMP and cGMP PDE and PEMT1. Using studies in the literature and results of our own work concerning some metabolic aspects of T lymphocytes in sarcoidosis, we present a revue of the various hypotheses, which involve dysfunction of cAMP signaling pathways, such as RAS/RAF/MEK/ERK in T lymphocytes, leading to a disorder of immunity.

Altered MENIN expression disrupts the MAFA differentiation pathway in insulinoma.

The protein MENIN is the product of the multiple endocrine neoplasia type I (MEN1) gene. Altered MENIN expression is one of the few events that are clearly associated with foregut neuroendocrine tumours (NETs), classical oncogenes or tumour suppressors being not involved. One of the current challenges is to understand how alteration of MENIN expression contributes to the development of these tumours. We hypothesised that MENIN might regulate factors maintaining endocrine-differentiated functions. We chose the insulinoma model, a paradigmatic example of well-differentiated pancreatic NETs, to study whether MENIN interferes with the expression of v-MAF musculoaponeurotic fibrosarcoma oncogene homologue A (MAFA), a master glucose-dependent transcription factor in differentiated ß-cells. Immunohistochemical analysis of a series of human insulinomas revealed a correlated decrease in both MENIN and MAFA. Decreased MAFA expression resulting from targeted Men1 ablation was also consistently observed in mouse insulinomas. In vitro analyses using insulinoma cell lines showed that MENIN regulated MAFA protein and mRNA levels, and bound to Mafa promoter sequences. MENIN knockdown concomitantly decreased mRNA expression of both Mafa and ß-cell differentiation markers (Ins1/2, Gck, Slc2a2 and Pdx1) and, in parallel, increased the proliferation rate of tumours as measured by bromodeoxyuridine incorporation. Interestingly, MAFA knockdown alone also increased proliferation rate but did not affect the expression of candidate proliferation genes regulated by MENIN. Finally, MENIN variants with missense mutations detected in patients with MEN1 lost the WT MENIN properties to regulate MAFA. Together, our findings unveil a previously unsuspected MENIN/MAFA connection regarding control of the ß-cell differentiation/proliferation balance, which could contribute to tumorigenesis.

Screening of mutations in genes that predispose to hereditary paragangliomas and pheochromocytomas.

Thirty per cent of the paragangliomas and pheochromocytomas reported are hereditary. Mutations in SDHB, SDHC, SDHD, and more recently SDHAF2 and TMEM127 genes have been described in these hereditary tumors. We looked for mutations in these 5 genes in a series of 269 patients with paragangliomas and/or pheochromocytomas. The SDHB, SDHC, and SDHD genes were analyzed in a series of 269 unrelated index patients with paragangliomas and/or pheochromocytomas using dHPLC screening of point mutations followed by direct sequencing and Multiplex PCR Liquid Chromatography to detect large rearrangements confirmed by quantitative PCR. In a second phase, we adapted Multiplex PCR Liquid Chromatography to the SDHAF2 and TMEM127 genes. This method and direct sequencing were applied to 230 patients without the SDHB, C, D mutations. Of the 269 patients, 44 carried a mutation (16.3%). Thirty-seven different mutations were identified: 18 in SDHB (including 2 large deletions), 8 in SDHD, 6 in SDHC, 5 in TMEM127, and no mutations in SDHAF2. Thirteen mutations have not been published so far. An exhaustive study of the different genes is needed to make possible a familial genetic diagnosis in paraganglioma and pheochromocytoma hereditary syndromes. Although mutations in SDHC and TMEM127 are less frequent than mutations in SDHB and SDHD, they also have less evident clinical feature indicators. Analyzing SDHAF2 must be restricted to familial extra-adrenal paragangliomas. Multiplex PCR Liquid Chromatography is a sensitive, fast, and inexpensive method for screening large rearrangements, which are infrequent in these syndromes.

[Multiple spontaneous pneumothoraces revealing Birt-Hogg-Dube syndrome]. / Pneumothorax itératifs et spontanés révélant un syndrome de Birt-Hogg-Dubé.

The Birt-Hogg-Dubé (BHD) syndrome is associated with cutaneous disorders including fibrofolliculomas and trichodiscomas, and also lung pneumatocysts and kidney tumours. The BHD syndrome occurs as a consequence of an autosomal dominantly inherited genodermatosis, linked to multiple germline mutations in the 14 exons of the BHD gene, mapped on 17p11.2 and encoding for folliculin (FLCN). The size and number of lung pneumatocysts are extremely variable and the cysts are surrounded by normal pulmonary tissue. In the absence of smoking lung function is usually unimpaired. The lung cysts are frequently complicated by the development of recurrent pneumothoraces. Treatment of pneumothorax in patients with the BHD syndrome is similar to the approach taken for patients with spontaneous pneumothorax. Lung cysts in the BHD syndrome are a rare cause of cystic pulmonary lesions. However, they must be systematically evaluated since kidney tumours occur in one third of patients. We report a case of classical BHD syndrome with specific cutaneous involvement, recurrent pneumothoraces complicating lung cysts, an exon 12 germline mutation on BHD gene and a familial history suggesting other related cases. This observation allows us to update this orphan disease, to consider BHD in the differential diagnosis of lung cysts and, above all, to highlight the high frequency and the prognostic significance of associated kidney tumours.

[Genomic profiling by comparative genomic hybridization: analysis of ten enucleated uveal melanoma cases]. / Apport de l'analyse par hybridation comparative génomique dans le mélanome uvéal : étude de dix cas énucléés.

AIM: To detect major chromosomal aberrations from enucleated uveal melanoma and relate them to hepatic metastasis and survival. PATIENTS AND METHODS: Ten uveal melanomas enucleated between 2005 and 2008 in the Lyon Croix-Rousse Hospital were retrospectively analyzed using a 19 000-clone comparative genomic hybridization microarray. RESULTS: The most frequent imbalances were the loss of chromosome 3 (8/10), gain of the 8q arm (7/10) or the entire chromosome 8 (2/10), and gain of the 6p arm (2/10). Most metastatic tumors (6/7) and all cases of death (5/5) concerned melanoma with monosomy 3 and gain of the 8q arm. DISCUSSION AND CONCLUSION: Genome-wide array comparative genomic hybridization is a reliable tool for identifying uveal melanoma genomic imbalances. Gains of the 8q arm with monosomy 3 are frequent and are strongly associated with poor outcome. Gains of the 6p arm are rare and have a better prognosis. There is a mutually exclusive relationship between monosomy 3 and chromosome 6 abnormalities in our study. These results confirm previously published reports.

The syndrome of gastric carcinoid and hyperparathyroidism: a family study and literature review.

OBJECTIVE: To present evidence supporting the hypothesis that the coexistence of gastric carcinoids (GCs) and hyperparathyroidism may represent a distinct clinical entity, not related to multiple endocrine neoplasia type 1 (MEN1). METHODS: We studied a cohort of five young siblings (age range 26-42 years), one of whom had been found to have GC and hyperparathyroidism. All siblings underwent serial gastroscopies for the assessment of gastric neuroendocrine cell proliferations over a mean follow-up period of 31.2 months. Imaging, biochemical and hormonal as well as molecular genetic investigations were performed in the direction of MEN1 syndrome. The literature was searched for cases with coexistence of GCs and hyperparathyroidism not associated with MEN1. RESULTS: Four of the siblings, all male, were found to have GCs in a background of Helicobacter pylori-associated chronic atrophic gastritis and pernicious anaemia, with no serological evidence of gastric autoimmunity. In two of them, asymptomatic hyperparathyroidism was also present. Screening for MEN1 gene mutations or large deletions was negative, and hormone and imaging investigations did not support a diagnosis of familial MEN1 syndrome. A literature search revealed sporadic reports of cases with GC and hyperparathyroidism not attributable to MEN1. CONCLUSIONS: The association of GCs and hyperparathyroidism appears to constitute a distinct syndrome that can be encountered in genetically predisposed individuals, and should not be regarded as 'atypical' or 'incomplete' expression of MEN1. Its prevalence and aetiology should be the subject of future studies. Screening for hyperparathyroidism seems to be justified in patients with GC of any type.

Homozygous variant rs2076530 of BTNL2 and familial sarcoidosis.

RATIONALE: Despite extensive studies, the pathogenesis of sarcoidosis is largely unknown. Although multiple environmental and putative infectious agents have been proposed, none was retained as a major contributor to the disease occurrence. Genetic predisposition to sarcoidosis was considered as a significant factor and numerous candidate genes have been reviewed. This last point was reinforced since the discovery of a pathogenic polymorphism (rs2076530 or G > A) of the BTNL2 gene, leading to an early truncation of the protein, which increases the relative risk of the disease. BTNL2 is known to act as a co-stimulatory molecule, inducing a negative signal to T-lymphocyte activation and the mutated gene is responsible for a truncated protein and disruption of membrane localization. OBJECTIVES: Our work attempted to confirm this observation in a highly penetrant familial form of sarcoidosis. RESULTS: In this family, the disease was diagnosed in 5 members through 3 generations. Despite individual clinical specificities, all displayed severe forms of the disease. Peripheral blood samples were collected from 3 patients and 2 additional healthy children of the fourth generation. Analysis of the BTNL2 gene confirmed the presence of the pathogenic variant of BTNL2 on both alleles (A/A homozygous genotype) in all subjects tested. CONCLUSIONS: Our data suggest that the absence of a membrane anchored BTNL2 protein may increase genetic susceptibility to sarcoidosis and familial occurrence of the disease. This observation assessed the putative pathogenic involvement of the rs2076530 variant of BTNL2 in the development of this granulomatosis disease.

Is the early-onset torsion dystonia (EOTD) linked to TOR1A gene as frequent as expected in France?

Early onset torsion dystonia are rare movement disorders. Molecular defect is known for only a subgroup, consisting of a unique and recurrent mutation in the TOR1A gene. We undertook a nationwide census of French TOR1A-mutation carriers and the assessment of clinical associated signs. Overall, 53 index cases and 104 relatives were studied and haplotypes linked to the mutation constructed. The previously reported Ashkenazi-Jewish haplotype was found in 11 families with the remainder carrying distinct haplotypes suggesting independent mutation events. This study demonstrates the scarcity of this disease in France with estimated disease frequency of 0.13:100,000 and mutation frequency of 0.17:100,000.

Familial pituitary adenomas with a heterogeneous functional pattern: clinical and genetic features.

Familial pituitary adenoma is a rare syndrome which may present either as isolated lesions, or in association with other endocrine tumors, for example in the frame of multiple endocrine neoplasia (MEN-1) or Carney complex (CNC). The most frequently described forms of familial isolated pituitary adenoma (FIPA) are familial somatotropinomas or prolactinomas. Recently, some cases of familial isolated somatotropinoma have been associated with germline mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene. The present report shows heterogeneous FIPA with 3 subtypes of tumor in 3 individuals of the same family: somatotropinoma in the proband, giant prolactinoma in a brother, and gonadotroph cell macroadenoma in the father. A prospective survey also suggested the occurrence of a silent microadenoma in the proband's sister. Clinical screening was performed in the 3 affected members, the 4th suspected case, and 9 additional, asymptomatic relatives. They had no clinical evidence of associated endocrine lesion suggesting MEN-1 or CNC. Genetic screening for germline mutation of the MEN-1, the gene encoding the protein kinase A (PKA) type 1 alpha regulatory subunit (R1 alpha) (PRKAR1alpha) and AIP gene was negative in 2 affected members. In conclusion, these data suggest that familial pituitary adenomas can occur with a heterogeneous functional pattern that is distinguished from MEN-1 or CNC. The absence of mutation of the recently described AIP gene suggests the implication of other predisposing gene(s). Collaborative, multicentric studies are needed to further define the location of gene(s) involved in heterogeneous FIPA.

[A Multiple endocrine neoplasia type-1 observatory in a French-speaking area. A tool from the Endocrine Tumor study Group (GTE)]. / Observatoire francophone des néoplasies endocriniennes multiples de type 1. Un outil du Groupe d'étude des Tumeurs Endocrines (GTE).

Wermer's syndrome or Multiple Endocrine Neoplasia Type-1 (MEN1) is an autosomal dominant inherited disease, related to mutations in MEN1, an approximately 10-kb gene encoding menin, localized on chromosome 11q13. The Endocrine Tumor Group (GTE) has set up a MEN1 observatory of 1001 regularly followed MEN1 cases. This observatory aims at registering and evaluating MEN1 cases in a large cohort. Any new study on a particular unexplored aspect of the disease may be proposed by a physician to the GTE. This article describes the way to diagnose a new MEN1 case and to register it. Procedures for participating in a new study are presented. Some original results are quoted.

Clinical characterization of familial isolated pituitary adenomas.

CONTEXT: Familial pituitary adenomas occur rarely in the absence of multiple endocrine neoplasia type 1 (MEN1) and Carney complex (CNC). OBJECTIVE: Our objective was to characterize the clinical and genealogical features of non-MEN1/CNC familial isolated pituitary adenomas (FIPA). DESIGN AND SETTING: We conducted a retrospective study of clinical and genealogical characteristics of FIPA cases and performed a comparison with a sporadic population at 22 university hospitals in Belgium, Italy, France, and The Netherlands. RESULTS: Sixty-four FIPA families including 138 affected individuals were identified [55 prolactinomas, 47 somatotropinomas, 28 nonsecreting adenomas (NS), and eight ACTH-secreting tumors]. Cases were MEN1/PRKAR1A-mutation negative. First-degree relationships predominated (75.6%) among affected individuals. A single tumor phenotype occurred in 30 families (homogeneous), and heterogeneous phenotypes occurred in 34 families. FIPA cases were younger at diagnosis than sporadic cases (P = 0.015); tumors were diagnosed earlier in the first vs. the second generation of multigenerational families. Macroadenomas were more frequent in heterogeneous vs. homogeneous FIPA families (P = 0.036). Prolactinomas from heterogeneous families were larger and had more frequent suprasellar extension (P = 0.004) than sporadic cases. Somatotropinomas occurred as isolated familial somatotropinoma cases and within heterogeneous FIPA families; isolated familial somatotropinoma cases represented 18% of FIPA cases and were younger at diagnosis than patients with sporadic somatotropinomas. Familial NS cases were younger at diagnosis (P = 0.03) and had more frequently invasive tumors (P = 0.024) than sporadic cases. CONCLUSIONS: Homogeneous and heterogeneous expression of prolactinomas, somatotropinomas, NS, and Cushing's disease can occur within families in the absence of MEN1/CNC. FIPA and sporadic cases have differing clinical characteristics. FIPA may represent a novel endocrine neoplasia classification that requires further genetic characterization.

[Genetics of endocrine tumours]. / Génétique des tumeurs endocrines.

Major advances have been made in the understanding of the genetic mechanisms underlying endocrine tumorigenesis, through the study of several syndromes of genetic predisposition and the identification of the genes involved. The syndrome of type 1 multiple endocrine neoplasia (MEN-1) is one of the best known; this autosomal dominant hereditary syndrome predisposes to the development of endocrine tumors of the pituitary, the parathyroids, the foregut and the adrenals. The responsible gene, known as MEN-1, encodes an original protein, menin, involved in several major cellular functions, such as the control of cell proliferation and differentiation. Type 2 multiple endocrine neoplasia (MEN-2) is an autosomal dominant hereditary syndrome associated with the development of medullary carcinomas of the thyroid, pheochromocytomas and hyperparathyroidism; the corresponding gene, RET, encodes a transmembrane receptor with tyrosine kinase activity. Endocrine tumors are also associated with non Hippel-Lindau disease and with phacomatoses, such as type 1 neurofibromatosis and tuberous sclerosis. Finally, isolated familial syndromes of endocrine tumors have been described: isolated familial hyperparathyroidism type II (HRPT2), associated with alterations in a gene coding for an original protein, parafibromin, or isolated familial syndromes of pheochromocytomas and paragangliomas (PRG) associated with mutations in the genes SDHB, SDHC or SDHD, which encode succinate-dehydrogenase subunits. The understanding of the genetic mechanisms underlying these syndromes of predisposition is essential for the diagnosis and management of these patients and their family; it also gives insight on the molecular mechanisms of endocrine tumorigenesis.

[Gastrinomas in multiple endocrine neoplasia type-1. A 127-case cohort study from the endocrine tumor group (ETG)]. / Les gastrinomes dans les néoplasies endocriniennes multiples de type 1. Une étude de cohorte de 127 cas du groupe des tumeurs endocrines (GTE).

UNLABELLED: On July 2000, 127 gastrinomas (31.1%) were studied by the Endocrine Tumour Group (GTE) using a 408-patient cohort of Multiple Endocrine Neoplasia Type 1 patients. The aim of this study was to assess clinical, biological, surgical data as well as their trends over three periods (<1980-1980/1989->1990). A Zollinger-Ellison syndrome (SZE) was present in 96% of the cases. Mean age at the onset of the disease was 39.4 years. There were 55.9% of men. Synchronous liver metastasis was present in 7.1%. Taken independently, the positivity of the four main diagnosis tests decreased over the time. The diagnosis of oesophagitis increased (4.5-29.7%), as well as the size of the resected tumours (9.9-16.8 mm). There was an increase in the familial background diagnosis (73.1-80%), an increasing use of Octreoscan scintigraphy and transduodenal ultrasound with positive detection of metastasis and tumours in 81.3% and 92.3%, respectively after 1991. Patients were operated on less frequently (96-52.5%), less frequently from the pancreas (87.5-37.5%), and from the gastro-intestinal tract (70.8-30%). The relative percentage of major pancreatic resections increased (with at least removal of the duodenum and the pancreatic head) (10-26.7%). The operative mortality disappeared. Six out of the seven patients (85.7%) who benefited from major pancreatic resections normalized their gastrine level postoperatively versus 15% in less radical techniques. Overall 5 years survival was 90 +/- 4.4%. Survival increased after 1985 (85 +/- 4.8% versus 95 +/- 3.6, P = 0.1). CONCLUSION: SZE in NEM1 were diagnosed at an earlier stage and were less frequently operated on. Nevertheless, the incidence of synchronous metastasis did not change significantly. Patients were mainly operated on for gastric emergencies and pancreatic tumours in order to prevent metastasis without mortality after 1991.