Challenges in Whole Exome Sequencing: An Example from Hereditary Deafness

Whole exome sequencing provides unprecedented opportunities to identify causative DNA variants in rare Mendelian disorders. Finding the responsible mutation via traditional methods in families with hearing loss is difficult due to a high degree of genetic heterogeneity. In this study we combined autozygosity mapping and whole exome sequencing in a family with 3 affected children having nonsyndromic hearing loss born to consanguineous parents. Two novel missense homozygous variants, c.508C>A (p.H170N) in GIPC3 and c.1328C>T (p.T443M) in ZNF57, were identified in the same ∼6 Mb autozygous region on chromosome 19 in affected members of the family. Both variants co-segregated with the phenotype and were absent in 335 ethnicity-matched controls. Biallelic GIPC3 mutations have recently been reported to cause autosomal recessive nonsyndromic sensorineural hearing loss. Thus we conclude that the hearing loss in the family described in this report is caused by a novel missense mutation in GIPC3. Identified variant in GIPC3 had a low read depth, which was initially filtered out during the analysis leaving ZNF57 as the only potential causative gene. This study highlights some of the challenges in the analyses of whole exome data in the bid to establish the true causative variant in Mendelian disease

The serine protease domain of MASP-3: enzymatic properties and crystal structure in complex with ecotin.

International audienceMannan-binding lectin (MBL), ficolins and collectin-11 are known to associate with three homologous modular proteases, the MBL-Associated Serine Proteases (MASPs). The crystal structures of the catalytic domains of MASP-1 and MASP-2 have been solved, but the structure of the corresponding domain of MASP-3 remains unknown. A link between mutations in the MASP1/3 gene and the rare autosomal recessive 3MC (Mingarelli, Malpuech, Michels and Carnevale,) syndrome, characterized by various developmental disorders, was discovered recently, revealing an unexpected important role of MASP-3 in early developmental processes. To gain a first insight into the enzymatic and structural properties of MASP-3, a recombinant form of its serine protease (SP) domain was produced and characterized. The amidolytic activity of this domain on fluorescent peptidyl-aminomethylcoumarin substrates was shown to be considerably lower than that of other members of the C1r/C1s/MASP family. The E. coli protease inhibitor ecotin bound to the SP domains of MASP-3 and MASP-2, whereas no significant interaction was detected with MASP-1, C1r and C1s. A tetrameric complex comprising an ecotin dimer and two MASP-3 SP domains was isolated and its crystal structure was solved and refined to 3.2 Å. Analysis of the ecotin/MASP-3 interfaces allows a better understanding of the differential reactivity of the C1r/C1s/MASP protease family members towards ecotin, and comparison of the MASP-3 SP domain structure with those of other trypsin-like proteases yields novel hypotheses accounting for its zymogen-like properties in vitro

Diuretics DIURETIKLER

Many cardiovascular disease interfere with the normal renal excretion of sodium, chloride and water, leading to their retention in an expanded extracellular fluid compartment. Diuretic drugs promote the renal loss of solutes and water. In spite of their use since more than 60 years the long-term effects, role on electrolyte disturbances, the neurohumoral system, effects on mortality and the risk/benefit ratio was evaluated in a few extensive clinical trials. The article looks over the general characteristics of diuretics, their use in cardiovascular disease, effects and side-effects on the basis of new trials and literature in this field

Comparison of the first dose response of fosinopril and captopril in congestive heart failure: A randomized, double-blin, placebo controlled study

The purpose of this study was to compare the safety and tolerability of recommended initial doses of fosinopril (FOS) with those of captopril (CAP), in diuretic-treated, salt depleted "high risk" patients with congestive heart failure. Thirty patients were randomized in a double blind fashion to receive a single dose of either FOS 10 mg, CAP 6.25 mg or placebo. CAP produced a significant early and brief fall in BP, while the first-dose hypotensive response with FOS did not differ significantly from placebo. Baseline plasma angiotensin converting enzyme (ACE) activity was similar in all groups. Only CAP showed an acute and significant fall in plasma ACE activity, whereas FOS and placebo did not change ACE activity. There was no correlation between mean arterial pressure or percentile change in mean arterial pressure and plasma ACE activity. Also no correlation was found between high or low ACE activity level and first dose hypotension. The practical importance of the results are: For patients with congestive heart failure, FOS and CAP have different effects on BP after the first dose, and this effect may be dependent on the plasma ACE activity level. FOS produces ACE inhibition and BP changes similar to placebo so it is the safer choice for the treatment of congestive heart failure

Comparison of the first dose response of Fosinopril and Captopril in congestive heart failure: a randomized, double-blind, placebo controlled study

The purpose of this study was to compare the safety and tolerability of recommended initial doses of a long-acting angiotensin converting enzyme inhibitor (ACE-I)Fosinopril (FOS) with those of a short-acting ACE-I Captopril (CAP) in diuretic-treated, salt deplete"high risk"patients with CHF. 30 patients were randomized in a double blind fashion to recieve a single dose of either FOS 10 mg or CAP 6.25 mg or placebo.Maximal fall in MAP after theraphy within 24 h was respectively -31%,-22%,-20% (FOS-CAP, p<0.05; FOS - plasebo, p=n.s), The practical importance of the results are: Oral ACE-inhibitors have different effects on the BP after the first dose, this effect does not dependent on the plasma ACE-A level,though FOS produced ACE-I similar to CAP and BP changes similar to placebo, so it is safer in the treatment of CHF

Biochemical evaluation of oxidative stress during exercise in patients with coronary heart disease

The impact of exercise tolerance test on oxidative stress was assessed by thiobarbituric acid reactive substances and markers of antioxidant status, namely Cu Zn superoxide dismutase, glutathione peroxidase, glutathione and vitamin E in blood samples of patients with exertional angina. The study was aimed to differentiate patients with positive exercise test (coronary heart disease patients) from patients with negative exercise test, at rest and peak exercise with respect to the investigated variables. Significantly lower values for both glutathione peroxidase activity and glutathione level were observed in patients after exercise test (p<0.01 and p<0.05, respectively). Only the patients with positive exercise test had significantly lower values for Cu Zn superoxide dismutase, glutathione peroxidase and glutathione, and a significantly higher ratio of thiobarbituric acid reactive substances/glutathione after exercise, as compared to before (p<0.05, p<0.05, p<0.05, p<0.01, respectively). Our findings indicate that the exercise test applied to patients with exertional angina oxidatively stresses the erythrocytes to a greater extent in exercise test (+) patients than in exercise test (-) patients

Asymptomatic giant prolapsing right atrial myxoma: Comparison of transthoracic and transesophageal echocardiography in pre-operative evaluation

We present a 65 years old asymptomatic patient with a giant prolapsing right atrial myxoma diagnosed echocardiographically and compare the transthoracic echocardiography and transesophageal two-dimensional features. Transesophageal echocardiography yielded a more accurate measurement of the correct dimensions of the tumour as compared with pathological findings, it also demonstrated clearly existing calcifications, the attachment and precise site of tumour pedunculation, showed haemodynamic changes, eliminated the possibility of other tumour foci. Transesophageal echocardiography gave correct anatomical and surgical data pre-operatively