Genetic basis for variation in plasma IL-18 levels in persons with chronic hepatitis C virus and human immunodeficiency virus-1 infections.

Inflammasomes are multi-protein complexes integrating pathogen-triggered signaling leading to the generation of pro-inflammatory cytokines including interleukin-18 (IL-18). Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections are associated with elevated IL-18, suggesting inflammasome activation. However, there is marked person-to-person variation in the inflammasome response to HCV and HIV. We hypothesized that host genetics may explain this variation. To test this, we analyzed the associations of plasma IL-18 levels and polymorphisms in 10 genes in the inflammasome cascade. About 1538 participants with active HIV and/or HCV infection in three ancestry groups are included. Samples were genotyped using the Illumina Omni 1-quad and Omni 2.5 arrays. Linear regression analyses were performed to test the association of variants with log IL-18 including HCV and HIV infection status, and HIV RNA in each ancestry group and then meta-analyzed. Eleven highly correlated single-nucleotide polymorphisms (r2=0.98-1) in the IL-18-BCO2 region were significantly associated with log IL-18; each T allele of rs80011693 confers a decrease of 0.06 log pg ml-1 of IL-18 after adjusting for covariates (rs80011693; rs111311302 ß=-0.06, P-value=2.7 × 10-4). In conclusion, genetic variation in IL-18 is associated with IL-18 production in response to HIV and HCV infection, and may explain variability in the inflammatory outcomes of chronic viral infections.

Association between ACVR2A and early-onset preeclampsia: replication study in a Northeastern Brazilian population.

INTRODUCTION: Preeclampsia is a complex and heterogeneous disease with increased risk of maternal mortality, especially for earlier gestational onset. There is a great inconsistency regarding the genetics of preeclampsia across the literature. The gene Activin A receptor, type IIA (ACVR2A), was reported as associated to preeclampsia in Australian/New Zealand and Norwegian populations. The goal of this study was to validate this genetic association in a Brazilian population. METHODS: We performed a case-control study using 693 controls and 613 cases (443 preeclampsia, 64 eclampsia and 106 HELLP syndrome), from a Northeastern Brazilian population. Five single nucleotide polymorphisms (SNPs) in ACVR2A were tested for association through multiple logistic regression models. RESULTS: There was no statistical association with preeclampsia (per se), eclampsia or HELLP. However, by grouping preeclampsia in accordance to the gestational age at delivery, SNPs rs1424954 (OR = 1.86; 95% CI, 1.25-2.78; p = 0.002) and rs1014064 (OR = 1.77; 95% CI, 1.21-2.60; p = 0.004) were significantly associated with early onset preeclampsia (gestational age ≤ 34 weeks). The risk haplotype had a frequency of 0.468 in early preeclampsia compared to 0.316 in controls (p = 0.0008 and permuted p = 0.002). DISCUSSION: Activin A receptors are important in decidualization, trophoblast invasion and placentation processes during pregnancy. The gene ACVR2A was associated with the more severe early onset preeclampsia. This finding supports the hypothesis of different pathogenic mechanisms contributing to the early- and late-onset preeclampsia.

Genome-wide association study of hepatitis C virus- and cryoglobulin-related vasculitis.

The host genetic basis of mixed cryoglobulin vasculitis is not well understood and has not been studied in large cohorts. A genome-wide association study was conducted among 356 hepatitis C virus (HCV) RNA-positive individuals with cryoglobulin-related vasculitis and 447 ethnically matched, HCV RNA-positive controls. All cases had both serum cryoglobulins and a vasculitis syndrome. A total of 899 641 markers from the Illumina HumanOmni1-Quad chip were analyzed using logistic regression adjusted for sex, as well as genetically determined ancestry. Replication of select single-nucleotide polymorphisms (SNPs) was conducted using 91 cases and 180 controls, adjusting for sex and country of origin. The most significant associations were identified on chromosome 6 near the NOTCH4 and MHC class II genes. A genome-wide significant association was detected on chromosome 6 at SNP rs9461776 (odds ratio=2.16, P=1.16E-07) between HLA-DRB1 and DQA1: this association was further replicated in additional independent samples (meta-analysis P=7.1 × 10(-9)). A genome-wide significant association with cryoglobulin-related vasculitis was identified with SNPs near NOTCH4 and MHC Class II genes. The two regions are correlated and it is difficult to disentangle which gene is responsible for the association with mixed cryoglobulinemia vasculitis in this extended major histocompatibility complex region.

Admixture analysis of spontaneous hepatitis C virus clearance in individuals of African descent.

Hepatitis C virus (HCV) infects an estimated 3% of the global population with the majority of individuals (75-85%) failing to clear the virus without treatment, leading to chronic liver disease. Individuals of African descent have lower rates of clearance compared with individuals of European descent and this is not fully explained by social and environmental factors. This suggests that differences in genetic background may contribute to this difference in clinical outcome following HCV infection. Using 473 individuals and 792,721 single-nucleotide polymorphisms (SNPs) from a genome-wide association study (GWAS), we estimated local African ancestry across the genome. Using admixture mapping and logistic regression, we identified two regions of interest associated with spontaneous clearance of HCV (15q24, 20p12). A genome-wide significant variant was identified on chromosome 15 at the imputed SNP, rs55817928 (P=6.18 × 10(-8)) between the genes SCAPER and RCN. Each additional copy of the African ancestral C allele is associated with 2.4 times the odds of spontaneous clearance. Conditional analysis using this SNP in the logistic regression model explained one-third of the local ancestry association. Additionally, signals of selection in this area suggest positive selection due to some ancestral pathogen or environmental pressure in African, but not in European populations.

Unmet needs in immigrant cancer survivors: a cross-sectional population-based study.

PURPOSE: Social suffering, language difficulties, and cultural factors may all make the cancer experience more difficult for immigrants. This study aimed to document unmet needs, and variables associated with these, in a population-based sample of first-generation immigrants and Anglo-Australians who had survived cancer. METHODS: Participants were recruited via Australian cancer registries. Eligible cancer survivors had a new diagnosis 1-6 years earlier and were aged between 18 and 80 years at diagnosis. Eligible immigrant participants and parents were born in a country where Arabic, Chinese (Mandarin, Cantonese, and other dialects), or Greek is spoken, and they spoke one of these languages. A random sample of English-speaking Anglo-Australian-born controls was recruited. RESULTS: Five hundred ninety-six patients (277 immigrants) were recruited to the study (response rate, 26%). Compared to Anglo-Australians, the adjusted odds ratio of Chinese immigrants for at least one unmet information/support need was 5.1 (95% CI 3.1, 8.3) and for any unmet physical need was 3.1 (95% CI 1.9, 5.1). For Greek, these were 2.0 (95% CI 1.1, 4.0) and 2.7 (95% CI 1.4, 5.2). Arabic patients had elevated, but not statistically significant, odds ratios compared to Anglo-Australians. Written information and having a specialist, support services, and other health professionals who spoke their language were in the top ten unmet needs amongst immigrants. CONCLUSION: Immigrant cancer survivors, several years after initial diagnosis, are more likely to have an unmet need for information or for help with a physical problem than Anglo-Australians. They strongly desire information and support in their own language.

Fine needle aspiration diagnosis of ipsilateral synchronous neoplasm - mucoepidermoid carcinoma with warthin tumor in parotid gland.

Warthin tumor (WT) owing to its heterogeneous appearance, biological behavior and multicentricity poses a diagnostic challenge to cytologists worldwide. We report a rare double pathology of mucoepidermoid carcinoma (MEC) with WT which was diagnosed by fine needle aspiration (FNA). Cytological smears revealed sheets of epithelial cells and small clusters of squamous cells in a background of mucoid material along with a few small groups and scattered oncocytic cells and inflammatory cells (mainly lymphocytes). In view of the cytological findings various differentials such as oncocytic lesions, benign lesions of the parotid with extensive lymphoid reaction, necrotizing sialometaplasia, WT with extensive squamous/mucoid metaplasia, metastatic squamous cell carcinoma (SCC) with or without cystic change, oncocytic variant of MEC and a possibility of a synchronous MEC with WT were considered. By means of extensive review of the smears and clinic-pathological meets as discussed below, 2 differential diagnoses were given- MEC with WT versus an oncocytic variant of MEC with "?" lymphoid (tumor response) reaction. Subsequent histopathological examination confirmed the diagnosis of MEC with WT. Recent discovery of t(11; 19) translocation generating a novel fusion gene CRTC1/MAML2 which has been demonstrated in both MEC and WT has helped in providing the missing link in confirming the genetic relatedness and proof of development of a subset of WT with concomitant MEC. The case discusses the FNA findings of a rare collision tumor (MEC with WT), its possible differentials and highlights the importance of noting the background material in a case of double pathology on FNA.

Leptin signaling in intestinal epithelium mediates resistance to enteric infection by Entamoeba histolytica.

Leptin is an adipocytokine that links nutrition to immunity. Previous observation that a genetic polymorphism in the leptin receptor affected susceptibility to Entamoeba histolytica infection led to the hypothesis that leptin signaling has a protective role during intestinal amebic infection. In this study we show that mice lacking the functional leptin receptor developed devastating mucosal destruction after E. histolytica infection. Bone marrow chimera experiments demonstrated that leptin receptor expressed on hematopoietic cells was not sufficient to confer resistance. Similarly, peripheral knockout of the leptin receptor rendered animals susceptible, indicating that central expression of the leptin receptor was not sufficient to confer protection. The site of leptin action was localized to the gut via an intestinal epithelium-specific deletion of the leptin receptor, which rendered mice susceptible to infection and mucosal destruction by the parasite. Mutation of tyrosine 985 or 1138 in the intracellular domain of the leptin receptor, which mediates signaling through the SH2-containing tyrosine phosphatase/extracellular signal-regulated kinase (SHP2/ERK) and signal transducer and activator of transcription 3 (STAT3) pathways, respectively, demonstrated that both were important for mucosal protection. We conclude that leptin-mediated resistance to amebiasis is via its actions on intestinal epithelium rather than hematopoietic cells or the brain, and requires leptin receptor signaling through both the STAT3 and SHP2/ERK pathways.

YAP dysregulation by phosphorylation or ΔNp63-mediated gene repression promotes proliferation, survival and migration in head and neck cancer subsets.

Overexpression of the Yes-associated protein (YAP), and TP53 family members ΔNp63 and p73, have been independently detected in subsets of head and neck squamous cell carcinomas (HNSCCs). YAP may serve as a nuclear cofactor with ΔNp63 and p73, but the functional role of YAP and their potential relationship in HNSCCs are unknown. In this study, we show that in a subset of HNSCC lines and tumors, YAP expression is increased but localized in the cytoplasm in association with increased AKT and YAP phosphorylation, and with decreased expression of ΔNp63 and p73. In another subset, YAP expression is decreased but detectable in the nucleus in association with lower AKT and YAP phosphorylation, and with increased ΔNp63 and p73 expression. Inhibiting AKT decreased serine-127 phosphorylation and enhanced nuclear translocation of YAP. ΔNp63 bound to the YAP promoter and suppressed its expression. Transfection of a YAP-serine-127-alanine phosphoacceptor-site mutant or ΔNp63 knockdown significantly increased nuclear YAP and cell death. Conversely, YAP knockdown enhanced cell proliferation, survival, migration and cisplatin chemoresistance. Thus, YAP function as a tumor suppressor may alternatively be dysregulated by AKT phosphorylation at serine-127 and cytoplasmic sequestration, or by transcriptional repression by ΔNp63, in different subsets of HNSCC. AKT and/or ΔNp63 are potential targets for enhancing YAP-mediated apoptosis and chemosensitivity in HNSCCs.

A variant in long palate, lung and nasal epithelium clone 1 is associated with cholera in a Bangladeshi population.

Vibrio cholerae causes a dehydrating diarrheal illness that can be rapidly fatal in the absence of specific treatment. The organism is an historic scourge and, like similar infectious diseases, may have influenced the evolution of the human genome. We report here the results of the first candidate gene association study of cholera. In a family-based study of 76 pedigrees from Dhaka, Bangladesh, we evaluated the association between cholera and five candidate genes-the cystic fibrosis transmembrane receptor; lactoferrin; long palate, lung and nasal epithelium clone 1 (LPLUNC1); estrogen-related receptor alpha and calcium-activated chloride channel 1. We found a significant association with a marker in the promoter region of LPLUNC1 (rs11906665), a member of a family of evolutionarily conserved innate immunity proteins. An earlier microarray-based study of duodenal biopsies showed significantly increased expression of LPLUNC1 in cholera patients compared with healthy control subjects. Our results suggest that variation in host innate immune responses may influence the outcome of exposure to V. cholerae in an endemic setting.

Genes at human chromosome 5q31.1 regulate delayed-type hypersensitivity responses associated with Leishmania chagasi infection.

Visceral leishmaniasis (VL) caused by Leishmania chagasi is endemic to northeast Brazil. A positive delayed-type hypersensitivity skin test response (DTH+) is a marker for acquired resistance to disease, clusters in families and may be genetically controlled. Twenty-three single nucleotide polymorphisms (SNPs) were genotyped in the cytokine 5q23.3-q31.1 region IRF1-IL5-IL13-IL4-IL9-LECT2-TGFBI in 102 families (323 DTH+; 190 DTH-; 123 VL individuals) from a VL endemic region in northeast Brazil. Data from 20 SNPs were analyzed for association with DTH+/- status and VL using family-based, stepwise conditional logistic regression analysis. Independent associations were observed between the DTH+ phenotype and markers in separate linkage disequilibrium blocks in LECT2 (OR 2.25; P=0.005; 95% CI=1.28-3.97) and TGFBI (OR 1.94; P=0.003; 95% CI=1.24-3.03). VL child/parent trios gave no evidence of association, but the DTH- phenotype was associated with SNP rs2070874 at IL4 (OR 3.14; P=0.006; 95% CI=1.38-7.14), and SNP rs30740 between LECT2 and TGFBI (OR 3.00; P=0.042; 95% CI=1.04-8.65). These results indicate several genes in the immune response gene cluster at 5q23.3-q31.1 influence outcomes of L. chagasi infection in this region of Brazil.

Safety of paracentesis in inpatients.

INTRODUCTION: Prior research has suggested that paracentesis is free from complications such as acute renal failure (ARF) providing albumin is administered. Actual safety of paracentesis > 1,000 ml was assessed at a tertiary care hospital. METHODS: 300 inpatient paracenteses performed between 12/99 and 4/04 were identified by coding records, of which 40 procedures were excluded due to lack of pre- or post-procedure lab values. Charts were reviewed for serum creatinine (Scr) before and after procedures, ascites volume, and clinical outcomes. RESULTS: 44 deaths occurred after 260 paracenteses (16.9%). Among 33 patients with ARF, 13 (39.4%) died. Only 31/227 patients without ARF (13.7%) died (p < 0.001). Serum creatinine (Scr) > 1.6 mg/dl prior to paracentesis predicted a 22.5% rate of ARF, compared to 8% for Scr < 1.0 (p = 0.002). ARF increased as volume increased (9.9%, 12.4%, and 14.9%, for volumes of < 2,300, 2,300 - 3,200, and > 3,200 ml) but this trend did not have statistical significance (p = 0.426). ARF occurred in 11/69 (15.9%) of patients receiving albumin, compared to 22/191 (11.5%) of patients who did not (p = 0.462). CONCLUSIONS: Paracentesis in inpatients has significant rates of ARF and death. Scr > 1.6 prior to paracentesis predicts an increased rate of ARF. Development of ARF is associated with an increased rate of death. No advantage was demonstrated with administration of albumin. Pre- and post-paracentesis labwork should be routine in inpatients.

Unilateral choanal atresia: Presentation in adults.

Unilateral choanal atresia usually presents later in life than the bilateral one and may present in adults. We discuss three cases of unilateral choanal atresia, which have presented in adult age group and with complaints not clearly pointing to the diagnosis. The role of CT scan in diagnosis and nasal endoscope in the treatment has been discussed.

High prevalence of V37I genetic variant in the connexin-26 (GJB2) gene among non-syndromic hearing-impaired and control Thai individuals.

Hearing loss is highly prevalent with a worldwide incidence of 1-2 per 1000 newborns. Several previous studies have demonstrated that mutations of connexin 26 (Cx26 or GJB2) are responsible for most cases of the recessive non-syndromic sensorineural hearing loss (NSSHL). Certain mutations have been described frequently among various populations, which include 35delG, 167delT, and 235delC. Recently, a missense mutation, V37I, was reported as a pathogenic change in East Asian affected individuals. To identify genetic variants associated with NSSHL in Thai population, we performed mutation analysis of Cx26 in 166 unrelated probands with NSSHL and 205 controls. We identified seven novel genetic variants in Cx26. We also identified a high prevalence of the V37I mutation among both affected probands (11.1%) and control subjects (8.5%), which suggests that the pathologic role of V37I may be modified by other genes. Our data support previous studies that show heterogeneity in the frequencies and types of mutations in Cx26 within populations and among ethnicities and that before clinical significance and causality can be attributed to a genetic variant, functional characterization is necessary.

Genetic influence of CXCR6 chemokine receptor alleles on PCP-mediated AIDS progression among African Americans.

CXCR6 is a chemokine receptor and the primary coreceptor in SIV infection. A single nucleotide polymorphism 1469G-->A, results in a nonconservative change in codon 3 (CXCR6-E3K) of the N-terminus of the coreceptor. To investigate the relation between the chemokine receptor CXCR6 genotype and progression to Pneumocystis carinii pneumonia (PCP) and from PCP to death, we clinically assessed and genotyped 805 individuals from an African-American injection drug-using cohort in Baltimore, MD, USA, for this CXCR6-E3K polymorphism. The allele frequency of CXCR6-3K was high (44%) in African Americans and rare in European Americans (f<1%). Although time to AIDS and PCP was similar for all CXCR6 genotypes, the median survival time from PCP to death for the CXCR6-3E/E and CXCR6-3E/K genotype was 1.5 years compared to 3.1 years for the CXCR6-K/K genotype. Individuals homozygous or heterozygous for the CXCR6-3E allele were 5.6 times more likely to die a PCP-mediated AIDS-related death than were individuals homozygous for CXCR6-3K. This study shows an association between CXCR6 genotype and progression from PCP to death among African-Americans with HIV. We suggest that CXCR6 may play a role in late-stage HIV-1 infection and may alter the progression to death after initial infection with PCP.

Effects of leptin administration and feed restriction on thecal leucocytes in the preovulatory rat ovary and the effects of leptin on meiotic maturation, granulosa cell proliferation, steroid hormone and PGE2 release in cultured rat ovarian follicles.

Leptin is expressed by adipocytes and is thought to play a role in regulating food intake and in reproduction. It has been demonstrated that acute leptin administration to immature gonadotrophin-primed rats in vivo inhibits ovulation and causes a decline in food intake. However, feed restriction alone does not inhibit ovulation. Two experiments were designed to investigate the mechanism of leptin-induced inhibition of ovulation. In the first experiment, which was prompted by the importance of ovarian leucocytes in ovulation, the role of leucocytes in leptin-induced inhibition of ovulation was investigated. The second experiment investigated whether high leptin concentrations could inhibit other factors important to ovulation, such as meiotic competence of oocytes, granulosa cell proliferation, steroid or PGE(2) release, and interleukin 1beta production, in vitro. In the first experiment, the populations of neutrophils and monocytes-macrophages in the preovulatory follicles of gonadotrophin-primed, leptin-treated and -untreated rats were examined. A decrease in food intake, as a result of either leptin treatment or feed restriction, specifically reduced the numbers of neutrophils and monocytes-macrophages infiltrating the theca interna of preovulatory follicles without affecting the numbers found in the stroma. The findings show that reduced infiltration of thecal neutrophils and macrophages into preovulatory follicles is a response to reduced food intake. Furthermore, this reduction is not the direct cause of the leptin-induced inhibition of ovulation. In the second experiment, ovarian follicles were cultured for 4 or 12 h in the presence or absence of the following hormones: FSH (500 miu), insulin-like growth factor I (IGF-I) (50 ng ml(-1)), LH (100 ng ml(-1)) and leptin (300 ng ml(-1)). The results demonstrated that high concentrations of leptin in follicle culture do not affect meiotic maturation or steroid release, but tend to inhibit release of PGE 2 (although this result was not significant). DNA synthesis in granulosa cells was not inhibited by leptin in FSH- and IGF-I-supplemented culture media. These results are in agreement with previous studies that have shown that leptin inhibits the stimulatory effects of IGF-I on FSH-stimulated oestradiol production in rat granulosa cells without affecting progesterone production. In summary, leptin does not appear to have an adverse effect on the components of ovulation tested in this study, and therefore must impact on the ovulatory cascade in a way that remains to be defined.

Expression of the long (OB-RB) and short (OB-RA) forms of the leptin receptor throughout the oestrous cycle in the mature rat ovary.

Leptin is secreted by adipocytes and exerts its effects by interacting with the long form of the leptin receptor, OB-RB. The leptin protein and leptin receptors have been localized in the ovary, and acute leptin treatment directly inhibits ovulation in the rat ovary. It was hypothesized that expression of the leptin receptor gene varies throughout the oestrous cycle to modulate the sensitivity of the ovary to leptin. In this study, expression of genes for the long and short isoforms of the leptin receptor in the adult ovary was investigated at different stages of the rat oestrous cycle. Vaginal cytology was used to determine the stage of the oestrous cycle. Ovaries were collected and RNA was extracted for real-time RT-PCR analysis of leptin receptor gene expression. OB-RB gene expression was low in pro-oestrus (3.13 +/- 0.18 fg RNA per microg total DNA) and dioestrus II (2.52 +/- 0.19 fg RNA per microg total DNA) of the oestrous cycle, whereas expression was high in oestrus (5.9 +/- 0.27 fg RNA per microg total DNA) and dioestrus I (4.6 +/- 0.24 fg RNA per microg total DNA) (P < 0.001). Expression of the gene for the short form of the leptin receptor (OB-RA) was at a maximum in dioestrus I (65.5 +/- 0.8 fg RNA per ng total DNA), high in oestrus (39.0 +/- 0.8 fg RNA per ng total DNA) and low at pro-oestrus (5.0 +/- 0.2 fg RNA per ng total DNA) and dioestrus II (1.1 +/- 0.09 fg RNA per ng total DNA) (P < 0.001). Plasma oestradiol concentrations (pg ml-1) were highest at pro-oestrus (19.38 +/- 1.3), and similar at the remaining three stages studied (oestrus: 13.7 +/- 1.9; dioestrus I: 12.4 +/- 1.0; dioestrus II: 10.3 +/- 0.9) (P < 0.05). Plasma progesterone concentrations (ng ml-1) were higher in the luteal phases of the oestrous cycle (dioestrus I: 18.6 +/- 2.3; dioestrus II: 14.7 +/- 2.5) than during pro-oestrus (5.12 +/- 0.6) and oestrus (5.9 +/- 0.8) (P < 0.05). Plasma leptin concentrations were detectable only in pro-oestrus (0.35 +/- 0.05 ng ml(-1)) and were below the detection limit of the assay at other stages of the oestrous cycle. In summary, mRNA content for the long and short isoforms of the leptin receptor is lower in pro-oestrus and dioestrus II than in oestrus and dioestrus I of the rat oestrous cycle. The fluctuations in leptin receptor mRNA content may be a response to the concentrations of circulating steroid hormones and leptin. This research supports the initial hypothesis and shows that ovarian leptin receptor concentrations vary throughout the oestrous cycle in response to the changing environment of the ovary.

The in vivo and in vitro effects of exogenous leptin on ovulation in the rat.

Leptin, a hormonal product of the Lep gene, is expressed by adipocytes and is thought to play a role in regulating food intake and reproduction. The leptin protein has been localized in many reproductive tissues, including the ovary. Several publications indicate that the ovary is directly affected by leptin and that leptin may be a factor linking obesity and reproductive dysfunction. In this study, the effect of systemic leptin administration on ovulation in the rat ovary, both in vivo and in vitro, was investigated. Ip administration of leptin (30 microg at 3 hourly intervals for 15 h) to immature gonadotropin-primed rats caused a decline in ovulation in vivo, from 15.9+/-2.0 oocytes in the control animals to 5.3+/-1.6 oocytes in the leptin-treated animals (P < 0.001). Plasma progesterone and estradiol levels were analyzed immediately before ovulation, and neither was altered significantly in animals receiving the leptin treatment. Food consumption and body weight decreased following leptin treatment; however, a loss in body weight alone (pair-fed controls) was insufficient to explain the decrease in ovulation observed in the leptin-treated animals. In vitro perfusion of FSH-primed whole ovaries showed that treatment with leptin in combination with LH significantly decreased ovulations from 5.7+/-1.6 per ovary perfused with LH alone to 1.3+/-0.6 in those with LH and 1 microg/ml leptin (P < 0.05). Progesterone and estradiol levels in the samples taken during the perfusion period were unaffected by leptin treatment. In summary, leptin administration resulted in fewer ovulations, both in vivo and in vitro, but did not influence steroid levels. Systemic leptin administration at these doses can therefore inhibit ovulation, a process that occurs through a direct effect on the ovary.

Sodium channel abnormalities are infrequent in patients with long QT syndrome: identification of two novel SCN5A mutations.

Long QT syndrome (LQTS) is a heterogeneous disorder caused by mutations of at least five different loci. Three of these, LQT1, LQT2, and LQT5, encode potassium channel subunits. LQT3 encodes the cardiac-specific sodium channel, SCN5A. Previously reported LQTS-associated mutations of SCN5A include a recurring three amino acid deletion (DeltaKPQ1505-1507) in four different families, and four different missense mutations. We have examined the SCN5A gene in 88 index cases with LQTS, including four with Jervell and Lange-Nielsen syndrome and the remainder with Romano-Ward syndrome. Screening portions of DIII-DIV, where mutations have previously been found, showed that none of these patients has the three amino acid deletion, DeltaKPQ1505-1507, or the other four known mutations. We identified a novel missense mutation, T1645M, in the DIV; S4 voltage sensor immediately adjacent to the previously reported mutation R1644H. We also examined all of the additional pore-forming regions and voltage-sensing regions and discovered another novel mutation, T1304M, at the voltage-sensing region DIII; S4. Neither T1645M nor T1304M were seen in a panel of unaffected control individuals. Five of six T1304M gene carriers were symptomatic. In contrast to previous studies, QT(onset-c) was not a sensitive indicator of SCN5A-associated LQTS, at least in this family. These data suggest that mutations of SCN5A are responsible for only a small proportion of LQTS cases.

Multiple different missense mutations in the pore region of HERG in patients with long QT syndrome.

Long QT syndrome (LQTS), is an inherited cardiac disorder in which ventricular tachyarrhythmias predispose affected individuals to syncope, seizures, and sudden death. Characteristic electrocardiographic findings include a prolonged QT interval, T wave alternans, and notched T waves. We have screened LQTS patients from 89 families for mutations in the pore region of HERG , the K+ channel gene previously associated with chromosome 7-linked LQT2. In six unrelated LQTS kindreds, single-strand conformation polymorphism analyses identified aberrant conformers in all affected family members. These conformers were not seen in over 100 unaffected, unrelated control individuals, suggesting that they represent pathogenic LQTS mutations. DNA sequence analyses of the aberrant conformers demonstrated that they reflect five different missense mutations: V612L, A614V, N629D, N629S, and N633S. The missense mutation A614V was found in two unrelated families. Further functional studies will be required to determine what effect each of these changes may have on HERG channel function.

Mutation of the gene for IsK associated with both Jervell and Lange-Nielsen and Romano-Ward forms of Long-QT syndrome.

BACKGROUND: Long-QT syndrome (LQTS) is a disorder of ventricular repolarization characterized by a prolonged QT interval, syncope, seizures, and sudden death. Recently, three forms of LQTS have been shown to result from mutations in potassium or sodium ion channel genes: KVLQT1 for LQT1, HERG for LQT2, and SCN5A for LQT3. IsK, an apparent potassium channel subunit encoded by KCNE1 on chromosome 21, regulates both KVLQT1 and HERG. This relationship makes KCNE1 a likely candidate gene, because mutations of these genes are known to cause both the autosomal dominant Romano-Ward and recessive Jervell and Lange-Nielsen (JLN) forms of LQTS. METHODS AND RESULTS: We screened 84 unrelated patients with Romano-Ward and 4 with JLN for possible mutations in KCNE1. We identified one homozygous mutation in a JLN patient that results in the nonconservative substitution of Asn for Asp at amino acid 76. The patient is congenitally deaf-mute, with recurrent syncopal events and a greatly prolonged QTc interval. The proband's mother and half-sister are both heterozygous for this mutation. Remarkably, both these family members have prolonged QTc intervals and would have been classified as Romano-Ward patients if not for the proband's diagnosis of JLN. This mutation was not identified in more than 100 control individuals. CONCLUSIONS: These data provide strong evidence that KCNE1 mutations represent a fifth LQTS locus (LQT5). Further functional analysis, as well as the identification of more LQTS patients with KCNE1 mutations, will be important to confirm the role of IsK in LQTS.