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IntroductionInterstitial lung diseases (ILDs) can be caused by mutations in the SFTPA1 and SFTPA2 genes, which encode the surfactant protein (SP) complex SP-A. Only 11 SFTPA1 or SFTPA2 mutations have so far been reported worldwide, of which five have been functionally assessed. In the framework of ILD molecular diagnosis, we identified 14 independent patients with pathogenic SFTPA1 or SFTPA2 mutations. The present study aimed to functionally assess the 11 different mutations identified and to accurately describe the disease phenotype of the patients and their affected relatives.MethodsThe consequences of the 11 SFTPA1 or SFTPA2 mutations were analysed both in vitro, by studying the production and secretion of the corresponding mutated proteins and ex vivo, by analysing SP-A expression in lung tissue samples. The associated disease phenotypes were documented.ResultsFor the 11 identified mutations, protein production was preserved but secretion was abolished. The expression pattern of lung SP-A available in six patients was altered and the family history reported ILD and/or lung adenocarcinoma in 13 out of 14 families (93%). Among the 28 SFTPA1 or SFTPA2 mutation carriers, the mean age at ILD onset was 45 years (range 0.6–65 years) and 48% underwent lung transplantation (mean age 51 years). Seven carriers were asymptomatic.DiscussionThis study, which expands the molecular and clinical spectrum of SP-A disorders, shows that pathogenic SFTPA1 or SFTPA2 mutations share similar consequences for SP-A secretion in cell models and in lung tissue immunostaining, whereas they are associated with a highly variable phenotypic expression of disease, ranging from severe forms requiring lung transplantation to incomplete penetrance.

Interstitial lung diseases (ILDs) can be caused by mutations in theThe consequences of the 11For the 11 identified mutations, protein production was preserved but secretion was abolished. The expression pattern of lung SP-A available in six patients was altered and the family history reported ILD and/or lung adenocarcinoma in 13 out of 14 families (93%). Among the 28This study, which expands the molecular and clinical spectrum of SP-A disorders, shows that pathogenic

Background: Heterozygous mutations in the SFTPA1 and SFTPA2 genes, encoding the surfactant protein SP-A1 and SP-A2 have been associated with rare forms of familial IIP and lung adenocarcinoma. We previously described 11 new heterozygous SFTPA1 and SFTPA2 variations in 13 unrelated patients including one newborn. The study aims to analyze the pathogenicity of those variations. Methods: We first analyzed the intrafamilial segregation of the identified variations with IIP and lung cancer. The production and the secretion of the mutant proteins were subsequently studied in HEK293T cells transiently expressing the SP-A proteins carrying the variations. Finally, SP-A expression was assessed on lung tissues of the patients. Results: In the studied families (38 adults, 3 children), the variations segregated with either IIP and/or lung cancer (37%) with an incomplete penetrance of the disease phenotype. The mean age at onset of the IIP was 45 years (0-68). Nine of the variations were located in the highly conserved carbohydrate recognition domain of the protein. In vitro, the mutant proteins were produced but their secretion was absent (n=9) or altered (n=2). The lung expression of SP-A studied in 3 unrelated patients showed an increased expression of SP-A in the cytoplasm of hypertrophic type 2 alveolar cells. Discussion and conclusion: The 11 identified SFTPA1 and SFTPA2 variations are pathogenic. They are associated with IIP and with an increased risk of lung cancer. They were identified mainly in adults but also in children. The pathophysiological consequences of their abnormal secretion/expression remain to be elucidated.

Background: Idiopathic interstitial pneumonia (IIP) comprise a heterogeneous group of rare lung parenchyma disorders with high morbidity and mortality. They have been associated with an increased frequency of lung cancer. A genetic cause is identified in up to 20% of familial cases, telomerase and surfactant genes (SFTPA2, SFTPB, SFTPC, ABCA3) mutations being the first etiologies. Objectives:This study investigates the implication of SFTPA1 (NM_005411) in 12 families affected by IPF and lung cancer. Methods:SFTPA1 was sequenced by Sanger method in 12 unrelated index cases. An informed signed consent was obtained for each patient. New SFTPA1 variations were studied with functional experimentations. Results: A heterozygous missense disease-causing mutation (p.Trp211Arg, W211R), in SFTPA1, that encodes the Surfactant Protein (SP)-A1, was identified in a large family. The affected members, aged 7 months to 59 years, presented with various forms of IIP, and adenocarcinoma. The W211R mutation segregated in a dominant pathway with the disease. The mutation involved an amino-acid that is located in the carbohydrate recognition domain (CRD) of SP-A1 and involved a residue invariant throughout evolution in SP-A1, but also in SP-A2 and in other CRD-containing proteins. The W211R mutation impaired SP-A1 secretion, and an abnormal expression pattern of SP-A was found in the alveolar epithelium of lung tissue from a patient carrying the SFTPA1 mutation. Conclusion: This first report of the involvement of SFTPA1 in a Mendelian disorder unveils the key role of SP-A1 in the pathophysiology of IIP from infancy to elderly, and open up a new field of research on the mechanisms involved in IIP and lung cancer.

Background: The surfactant protein A (SP)-A is a collectin implicated in surfactant homeostasis, local alveolar immune response, and epithelial repair after lung injury. SP-A is encoded by the SFTPA1 and SFTPA2 genes. The aim of this study was to search for mutations in SFTPA1 and SFTPA2 in adult patients with ILD. Methods: All SFTPA1 and SFTPA2 exons and flanking intronic sequences were analyzed in a large prospective study population of 160 apparently unrelated ILD patients with no telomerase, SFTPC or ABCA3 mutations. Results: 86 patients were diagnosed with a familial form of ILD, of whom 20 presented an association with a familial lung cancer. 63 patients were Discussion and conclusion: Altered SP-A expression may contribute to ILD pathophysiology. Data reported herein indicate that patients with ILD and a personal or familial lung cancer, and/or

Gitelman’s syndrome is an autosomal recessive salt losing nephropathy caused by inactivated mutations of the SLC12A3 gene, encoding the NaCl cotransporter of the distal convoluted tubule. We report a French family with five affected members over two generations suggesting a dominant transmission. After SLC12A3 sequencing of seven individuals, four mutations were detected. Pseudo-dominant transmission was explained by the union of a compound heterozygous woman (two mutations on one allele and one mutation on the other) with a heterozygous healthy man. This study shows the importance of complete genetic analysis of families with unusual presentation.

OBJECTIVE We previously showed that fibromuscular dysplasia (FMD) of the renal artery may be familial. Case reports have associated alpha1-antitrypsin deficiency and FMD. The aim of this study was to test the implication of the alpha1-antitrypsin (AAT) gene in a large cohort of patients with renal FMD. MATERIALS AND METHODS A case-control study comparing the genotype frequencies in 161 consecutive patients with angiographically proven renal FMD with those observed in three sets of controls (353 hypertensive patients, 288 normotensive patients, 444 normotensive women) was conducted. High-resolution echotracking of the carotid and radial arteries was performed in a subset of 77 FMD patients. Three functional polymorphisms of the AAT gene (PiM1, PiZ, PiS) were investigated. RESULTS Clinical (age 44.3 +/- 13.8 years, 85.1% women) and radiological (77.1% of multifocal lesions) characteristics of the FMD population were consistent with those previously published. No differences were found in AAT genotype frequencies in the FMD subjects compared with the 1085 controls. We found no correlation between the AAT genotypes and the clinical and angiographical characteristics of the FMD patients. Echotracking results confirmed our previously published results in FMD patients with a specific pattern and a mean arterial phenotypic score greater than 3. However, no difference in the arterial score was observed across the genotypes. CONCLUSION Polymorphisms PiM1, PiZ and PiS of the AAT gene are not associated with renal FMD or infraclinical carotid lesions detected by echotracking methods. As the true prevalence of renal FMD is not precisely known and alpha1-antitrypsin deficiency is not infrequent in the general population, the association of the two may occur by chance.

Gitelman syndrome (GS) is a salt-wasting tubulopathy that results from the inactivation of the human thiazide-sensitive sodium chloride cotransporter located in the distal convoluted tubule. Tubular adaptation to renal sodium loss has been described and localized in the distal tubule in experimental models of GS but not in humans with GS.The tubular adaptation to renal sodium loss is described. Osmole-free water clearance and endogenous lithium clearance with furosemide infusion are used to compare 7 patients with genetically confirmed GS and 13 control participants.Neither endogenous lithium clearance nor osmole-free water clearance disclosed enhanced proximal fluid reabsorption in patients with GS. These patients displayed significantly lower osmole-free water clearance factored by inulin clearance (7.1 ± 1.9 versus 10.1 ± 2.2; P0.01) and significantly lower fractional sodium reabsorption in the diluting nephron (73.2% ± 7.1% versus 86.1% ± 4.7%; P0.005), consistent with the inactivation of the thiazide-sensitive sodium chloride cotransporter. The furosemide-induced reduction rate of fractional sodium reabsorption in the diluting segment was higher in patients with GS (75.6% ± 6.1% versus 69.9% ± 3.2%; P0.039), suggesting that sodium reabsorption would be enhanced in the cortical part of the thick ascending limb of the loop of Henle in patients with GS.These findings suggest that tubular adaptation to renal sodium loss in GS would be devoted to the cortical part of the thick ascending limb of the loop of Henle in humans.

Germ-line mutations in the genes encoding succinate dehydrogenase complex subunits B (SDHB) and D (SDHD) have been reported in familial paragangliomas and apparently sporadic phaeochromocytomas (ASP), but the genotype-phenotype relationships of these mutations are unknown. Eighty-four patients (all but 2 followed up for 8.8 +/- 5.7 years) with ASP (57 with adrenal tumors, 27 with extra-adrenal, multiple, malignant, or recurrent tumors) were screened for the major susceptibility genes for phaeochromocytoma (RET, VHL, SDHD, and SDHB). Thirty-three tumors were available for molecular analysis, enzyme assays, and immunohistochemistry. No (0%) RET and 2 (2.4%) VHL mutations were detected. Only two coding single nucleotide polymorphisms in the SDHD gene (G12S and H50R) were found in 6 patients (7%). Conversely, six deleterious mutations in the SDHB gene were identified in 8 patients (9.5%). Ectopic site and recurrence or malignancy were strongly associated with SDHB mutations (7 of 8, 87%, versus 20 of 76, 26%; P = 0.001). Somatic DNA analysis indicated a loss of heterozygosity at chromosome 1p36 (SDHB locus) in 16 of 33 cases (48%). A loss of heterozygosity at the SDHB locus was found in all tumors with SDHB mutation, and assays of respiratory chain enzymes showed a complete loss of complex II catalytic activity. The vascular architecture of tumors with SDHB mutations displayed features typical of malignancy. These data strongly suggest that SDHB gene is a tumor suppressor gene and that the identification of germ-line mutations in SDHB gene in patients with ASPs should be considered as a high-risk factor for malignancy or recurrence.