The Risk of Familial Mediterranean Fever in MEFV Heterozygotes: A Statistical Approach

Background

Familial Mediterranean fever (FMF) is an autosomal recessive autoinflammatory disorder due to MEFV mutations and one of the most frequent Mediterranean genetic diseases. The observation of many heterozygous patients in whom a second mutated allele was excluded led to the proposal that heterozygosity could be causal. However, heterozygosity might be coincidental in many patients due to the very high rate of mutations in Mediterranean populations.

Objective

To better delineate the pathogenicity of heterozygosity in order to improve genetic counselling and disease management.

Methods

Complementary statistical approaches were used: estimation of FMF prevalence at population levels, genotype comparison in siblings from 63 familial forms, and genotype study in 557 patients from four Mediterranean populations.

Results

At the population level, we did not observe any contribution of heterozygosity to disease prevalence. In affected siblings of patients carrying two MEFV mutations, 92% carry two mutated alleles, whereas 4% are heterozygous with typical FMF diagnosis. We demonstrated statistically that patients are more likely to be heterozygous than healthy individuals, as shown by the higher ratio heterozygous carriers/non carriers in patients (p<10⁻⁷–p<0.003). The risk for heterozygotes to develop FMF was estimated between 2.1×10⁻³ and 5.8×10⁻³ and the relative risk, as compared to non carriers, between 6.3 and 8.1.

Conclusions

This is the first statistical demonstration that heterozygosity is not responsible for classical Mendelian FMF per se, but constitutes a susceptibility factor for clinically-similar multifactorial forms of the disease. We also provide a first estimate of the risk for heterozygotes to develop FMF.     

Nosocomial meningitis caused by Staphylococcus other than S. aureus in children: multicentre study

Analysing 101 cases of nosocomial meningitis due to staphylococci other than S. aureus within last 15 years, coagulase negative staphylococci represented the commonest pathogen. Major risk factor for staphylococcal meningitis was prior neurosurgery, mainly ventriculoperitoneal shunt insertion. Ten of 101 cases were caused by glycopeptide intermediate resistant strains in patients pretreated with multiple combination of antibiotics including vancomycin and shunt exchanges: 76% of strains were also oxacillin resistant.     

Comparison of postsurgical and community acquired bacterial meningitis--analysis of 372 cases within a nationwide survey

The aim of this study was to assess if differences in etiology and risk factors among 372 cases of bacterial meningitis acquired after surgery (PM) or in community (CBM) have impact on outcome of infected patients. Among 372 cases of bacterial meningitis within last 17 years from 10 major Slovak hospitals, 171 were PM and 201 CBM. Etiology, risk factors such as underlying disease, cancer, diabetes alcoholism, surgery, VLBW, ENT infections, trauma, sepsis were recorded and mortality, survival with sequellae, therapy failure were compared in both groups. Significant differences in etiology and risk factors between both groups were reported. Those after neurosurgery had more frequently Coagulase negative staphylococci (p<0.001), Enterobacteriaceae (p=0.01) and Acinetobacter baumannii (p=0.0008) isolated from CSF and vice versa Streptococcus pneumoniae (p<0.001), Neisseria meningitis (p<0.001) and Haemophillus influenza (p=0.0009) were more commonly isolated from CSF in CBM. Neurosurgery (p<0.001), sepsis (p=0.006), VLBW neonates (p=0.00002) and cancer (p=0.0007) were more common in PM and alcohol abuse (p<0.001) as well as otitis/sinusitis (p<0.001) and Roma ethnic group (p=0.001) in CAM. Initial treatment success was significantly more frequently observed among CAM (p<0.001) but cure after modification was more common in PM (p=0.002). Therefore outcome in both groups was similar (14.6% vs. 12.4%, p=NS).     

Development and validation of an ion-pair reversed-phase high-performance liquid chromatographic method for the separation of phosphonodipeptides

The objective of this research was to develop a rapid, sensitive and reliable method for the separation of phosphonodipeptide prodrugs and parent compounds to facilitate the evaluation of cell permeation using in vitro cell culture models. Separation was accomplished isocratically within 10.0 min using a C₁₈ (150×4.6 mm I.D., 3 μm) reversed-phase column. The mobile phase consisted of 5 mM tetrahexyl ammonium (ion-pair reagent) in 0.02 M phosphate buffer pH 6.5-acetonitrile (48.5:51.5, v/v). The flow-rate was 1.1 ml/min with detection at 221 nm. The standard curves were linear (r²>0.999) over the concentration range 1–100 μM. The method was reliable and reproducible, with the limit of quantitation being 1 μM (25 ng on column).     

The DNA double-strand break repair gene hMRE11 is mutated in individuals with an ataxia-telangiectasia-like disorder

We show that hypomorphic mutations in hMRE11, but not in ATM, are present in certain individuals with an ataxia-telangiectasia-like disorder (ATLD). The cellular features resulting from these hMRE11 mutations are similar to those seen in A-T as well as NBS and include hypersensitivity to ionizing radiation, radioresistant DNA synthesis, and abrogation of ATM-dependent events, such as the activation of Jun kinase following exposure to gamma irradiation. Although the mutant hMre11 proteins retain some ability to interact with hRad50 and Nbs1, formation of ionizing radiation-induced hMre11 and Nbs1 foci was absent in hMRE11 mutant cells. These data demonstrate that ATM and the hMre11/hRad50/Nbs1 protein complex act in the same DNA damage response pathway and link hMre11 to the complex pathology of A-T.     

Recent origin of sub-Antarctic notothenioids

Comparison of partial mitochondrial 12S and 16S rDNA sequences from non-Antarctic notothenioid fishes - an icefish Champsocephalus esox and two members of the genus Patagonotothen - and their sister species from the Southern Ocean suggests that their divergence took place 1.7 and 6.6-7 million years ago, respectively, i.e. much later than the formation of the Antarctic Polar Front (20-25 million years ago).     

Residual ataxia telangiectasia mutated protein function in cells from ataxia telangiectasia patients, with 5762ins137 and 7271T-->G mutations, showing a less severe phenotype

We have assessed several ataxia Telangiectasia mutated (ATM)-dependent functions in cells derived from ataxia telangiectasia patients, carrying either an ATM 5762ins137 splice site or a 7271T-->G missense mutation, with a less severe phenotype compared with the classical disorder. ATM kinase in vitro, from 5762ins137 cells, showed the same specific activity as ATM in normal cells, but the protein was present at low levels. In contrast, mutant ATM kinase activity in the 7271T-->G cells was only about 6% that of the activity in normal cells, although the level of mutant protein expressed was similar to normal cells. Phosphorylation of the DNA double strand break repair proteins Nbs1 and hMre11, following DNA damage, was observed in normal and 7271T-->G cells but was almost absent in both 5762ins137 and classical ataxia telangiectasia cells. The kinetics of p53 response was intermediate between normal and classical ataxia telangiectasia cells in both the 7271T-->G and 5762ins137 cells, but interestingly, c-Jun kinase activation following DNA damage was equally deficient in cell lines derived from all the ataxia telangiectasia patients. Our results indicate that levels of ATM kinase activity, but not induction of p53 or c-Jun kinase activity, in these cells correlate with the degree of neurological disorder in the patients.     

Gender-related differences in susceptibility to oxidative stress in healthy middle-aged Serbian adults

Gender-related differences in the association between polymorphism of xenobiotic-metabolising enzymes or non-genetic biomarkers and susceptibility to oxidative stress was assessed in healthy middle-aged Serbian adults, by urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG/creatinine) and total antioxidant status in serum (TAOS). Females were more susceptible to oxidative stress. In both genders, positive predictor of the antioxidative protection was serum triglyceride, while BMI?<25?kg/m² was associated with oxidative stress. Susceptibility to oxidative stress in males was associated with GSTT1*null allele and increased serum iron, but in females, it was decreased serum bilirubin. Early identification of the risk factors could be important in the prevention of oxidative stress-related diseases.     

5,6-Dihydro-1H-pyridin-2-ones as potent inhibitors of HCV NS5B polymerase

5,6-Dihydro-1H-pyridin-2-one analogs were discovered as a novel class of inhibitors of genotype 1 HCV NS5B polymerase. Among these, compound 4ad displayed potent inhibitory activities in biochemical and replicon assays (IC₅₀ (1b) < 10 nM; IC₅₀ (1a) < 25 nM, EC₅₀ (1b) = 16 nM), good in vitro DMPK properties, as well as moderate oral bioavailability in monkeys (F = 24%).