A mutation in the Gardos channel is associated with hereditary xerocytosis.

The Gardos channel is a Ca(2+)-sensitive, intermediate conductance, potassium selective channel expressed in several tissues including erythrocytes and pancreas. In normal erythrocytes, it is involved in cell volume modification. Here, we report the identification of a dominantly inherited mutation in the Gardos channel in 2 unrelated families and its association with chronic hemolysis and dehydrated cells, also referred to as hereditary xerocytosis (HX). The affected individuals present chronic anemia that varies in severity. Their red cells exhibit a panel of various shape abnormalities such as elliptocytes, hemighosts, schizocytes, and very rare stomatocytic cells. The missense mutation concerns a highly conserved residue among species, located in the region interacting with Calmodulin and responsible for the channel opening and the K(+) efflux. Using 2-microelectrode experiments on Xenopus oocytes and patch-clamp electrophysiology on HEK293 cells, we demonstrated that the mutated channel exhibits a higher activity and a higher Ca(2+) sensitivity compared with the wild-type (WT) channel. The mutated channel remains sensitive to inhibition suggesting that treatment of this type of HX by a specific inhibitor of the Gardos channel could be considered. The identification of a KCNN4 mutation associated with chronic hemolysis constitutes the first report of a human disease caused by a defect of the Gardos channel.

Deciphering an isolated lung phenotype of NKX2-1 frameshift pathogenic variant.

Background: to perform a functional analysis of a new NK2 homeobox 1 (NKX2-1) variant (c.85_86del denominated NKX2-1DEL) identified in a family presenting with isolated respiratory disease, in comparison to another frameshift variant (c.254dup denominated NKX2-1DUP) identified in a subject with classical brain-lung-thyroid syndrome. Methods: pathogenic variants were introduced into the pcDNA3-1(+)-wt-TTF1 plasmid. The proteins obtained were analyzed by western blot assay. Subcellular localization was assessed by confocal microscopy in A549 and Nthy cells. Transactivation of SFTPA, SFTPB, SFTPC, and ABCA3 promoters was assessed in A549 cells. Thyroglobulin promoter activity was measured with the paired box gene 8 (PAX8) cofactor in Nthy cells. Results: The two sequence variants were predicted to produce aberrant proteins identical from the 86th amino acid, with deletion of their functional homeodomain, including the nuclear localization signal. However, 3D conformation prediction of the conformation prediction of the mutant protein assumed the presence of a nuclear localization signal, a bipartite sequence, confirmed by confocal microscopy showing both mutant proteins localized in the nucleus and cytoplasm. Transcriptional activity with SFTPA, SFTPB, SFTPC, ABCA3 and thyroglobulin promoters was significantly decreased with both variants. However, with NKX2-1DEL, thyroglobulin transcriptional activity was maintained with the addition of PAX8. Conclusion: These results provide novel insights into understanding the molecular mechanism of phenotypes associated with NKX2-1 pathogenic variants.

Determination of Prenatal Substance Exposure Using Meconium and Orbitrap Mass Spectrometry.

The aim of this study was to develop and to validate a toxicological untargeted screening relying on LC-HRMS in meconium including the detection of the four main classes of drugs of abuse (DoA; amphetamines, cannabinoids, opioids and cocaine). The method was then applied to 29 real samples. Analyses were performed with a liquid chromatography system coupled to a benchtop Orbitrap operating in a data-dependent analysis. The sample amount was 300 mg of meconium extracted twice by solid phase extraction following two distinct procedures. Raw data were processed using the Compound Discoverer 3.2 software (Thermo). The method was evaluated and validated on 15 compounds (6-MAM, morphine, buprenorphine, norbuprenorphine, methadone, EDDP, amphetamine, MDA, MDMA, methamphetamine, cocaine, benzoylecgonine, THC, 11-OH-THC, THC-COOH). Limits of detection were between 0.5 and 5 pg/mg and limits of identification between 5 and 50 pg/mg. Mean matrix effect was between -79 and -19% (n = 6) and mean overall recovery between 18 and 73% (n = 6) at 100 pg/mg. The application allows the detection of 88 substances, including 47 pharmaceuticals and 15 pharmaceutical metabolites, cocaine and its metabolites, THC and its metabolites, and natural (morphine, codeine) and synthetic (methadone, buprenorphine, tramadol, norfentanyl) opioids. This method is now used routinely for toxicological screening in high-risk pregnancies.

Non-lethal neonatal neuromuscular variant of glycogenosis type IV with novel GBE1 mutations.

We report a recent case of the severe congenital variant of glycogen storage disease type IV with prolonged survival. The patient was found to be a compound heterozygote for two novel mutations, a missense mutation in exon 5 (p.H188P, c.563A>C) and a severe mutation in intron 5 (c.691+2T>C). We propose that the genotype and the quality of medical care may account for the severe but non-lethal phenotype.

Fetal and neonatal consequences of antenatal exposure to type 1 angiotensin II receptor-antagonists.

Sartans are selective type 1 angiotensin II receptor-antagonists that are used in the treatment of arterial hypertension. Few reports are available concerning the use of sartans during pregnancy. We report two cases of adverse fetal outcome in hypertensive pregnancies exposed to sartans. In the first case, anamnios and fetal renal failure due to severe tubular dysgenesia led to termination of pregnancy in the 27th week. The second patient presented with hypocalvaria and developed fetal renal failure. The use of sartans during the two last trimesters of pregnancy should be strictly avoided.

Screening for retinopathy of prematurity: results of a retrospective 3-year study of 502 infants.

PURPOSE: To describe the surveillance, results of screening, and treatment of retinopathy of prematurity (ROP) in a university hospital setting in southeast France. PATIENTS AND METHODS: Five hundred two premature infants were included in the screening protocol between January 1997 and December 1999. Criteria for inclusion in the study were a gestational age of 32 weeks or younger, a birth weight of less than 1,501 g, or both. The first fundus examination was performed between 4 and 6 weeks of life. Thereafter, fundus examination was performed in the absence of ROP every 2 weeks until complete retinal vasculature developed, gestational age of 50 weeks, or death. Examination was weekly in cases of retinopathy, biweekly if progression was ascertained, and less frequent only if regression was evident. Hospital records were reviewed to assess the presence or absence and eventual degree of ROP. RESULTS: Stage 1 was observed in 32 infants, and stage 2 in 11 infants; all of these cases regressed. Three cases of bilateral stage 3 (two threshold and one prethreshold) disease underwent diode laser peripheral retinal ablation and regressed. One infant with bilateral stage 3 disease who underwent peripheral cryoablative surgery progressed to stage 4A in one eye and 4B in the other eye and then underwent scleral buckling surgery in the second eye. CONCLUSIONS: Despite survival increasing with improved neonatal intensive care, the incidence of ROP does not appear to be increasing. In our center, the incidence appears to be lower than previously reported.

Respiratory distress syndrome after elective caesarean section in near term infants: a 5-year cohort study.

OBJECTIVE: to assess the incidence of respiratory distress syndrome (RDS) in late preterm (34(0/7)-36(6/7)) and just term (37(0/7)-37(6/7)) infants born via elective caesarean section (CS) in a tertiary care maternity facility. METHODS: retrospective cohort study between 2005 and 2009. Hundred and eighty-eight near term infants, divided in two groups: group A: 125 late preterm (34(0/7)-36(6/7)) and group B: 63 just term (37(0/7)-37(6/7)), from elective CS (except CS after pre-mature rupture of membranes and foetuses presenting congenital malformation) were included. RESULTS: In group A the overall incidence of RDS (RDS at or shortly after birth, requiring respiratory support or oxygen therapy) was 44% (n = 55) vs. 15.9% (n = 10) in group B (p < 0.01). The incidence of SRDS (requiring admission in the neonatal intensive care unit (NICU)) in group A was 13.6% (n = 17) and 3.2% (n = 2) group B (p < 0.01). The risk decreased significantly as gestational age (GA) increased: for RDS, 50.9% at 34 weeks of gestation (WG), 52.5% at 35 WG, 21.5% at 36 WG, and 15.9% at 37 WG; for admission, 30.2% at 34 WG, 25% at 35 WG, 9.4% at 36 WG, and 6.3% at 37 WG. Among late preterm infants with RDS, 30.9% (n = 17) developed severe RDS (SRDS). CONCLUSIONS: Late preterm infants born via elective CS are at high risk for RDS and NICU admission. The risk is influenced by each additional week spent in utero. As the incidence of CS is increasing within this population, new preventative strategies must be sought.