Fetal phenotype associated with the 22q11 deletion.

The 22q11 deletion syndrome is one of the most common human microdeletion syndromes, with a wide spectrum of abnormalities. The fetal phenotype associated with the 22q11 deletion is poorly described in the literature. A national retrospective study was performed from 74 feto-pathological examinations. The objectives were to evaluate the circumstances of the 22q11 deletion diagnosis and to describe fetal anomalies. Post mortem examinations were performed after 66 terminations of pregnancy and eight fetal deaths. The series included nine fetuses from the first trimester, 55 from the second trimester, and ten from the third trimester. A 22q11 FISH analysis was recommended for 57 fetuses after multidisciplinary prenatal diagnostic counseling and for 17 fetuses by a fetal pathologist. Conotruncal heart defects were the most common anomalies (65 fetuses), followed by thymus defects (62 fetuses), and malformations of the urinary tract (25 fetuses). This study identified several unusual and severe features rarely described in the literature. Neurological abnormalities were described in ten fetuses, with seven neural tube defects and five arhinencephalies. This series also included lethal malformations: two hypoplastic left heart syndromes, two bilateral renal agenesis, and one tracheal agenesis. Genetic analysis for a 22q11 deletion is usually indicated when a congenital conotruncal heart and/or thymus defect is detected, but might also be useful in case of other lethal or severe malformations that initially led to the termination of pregnancy.

Effect of persistent patent ductus arteriosus on mortality and morbidity in very low-birthweight infants.

AIM: Because New Caledonia is geographically isolated from the nearest cardiac surgical centre, surgical closure of ductus arteriosus is not performed in very low-birthweight (VLBW) infants who have a persistent patent ductus in spite of having undergone treatment with ibuprofen. This study aimed at investigating the possible effect of persistent patent ductus in VLBW infants. METHODS: The study included 177 VLBW infants born at 25-31 weeks of gestation from January 2006 to May 2011. Mortality and major morbidities were compared between infants with a persistent patent ductus (n = 33) and those without it (n = 104). Statistical associations between potential neonatal risk factors and significant morbidities were identified using multivariate regression analyses. RESULTS: Rates of mortality and major morbidities, including the rate of bronchopulmonary dysplasia, necrotizing enterocolitis, intraventricular haemorrhage grades I-II and III-IV, periventricular leucomalacia, late-onset infections and failure of hearing screening, were insignificantly higher in VLBW infants with a persistent patent ductus than in those without it. CONCLUSION: This study adds further evidence that persistent patent ductus arteriosus has no significant effect on mortality and morbidity in VLBW infants born at ≥25 weeks' gestational age.

Two type III secretion system effectors from Ralstonia solanacearum GMI1000 determine host-range specificity on tobacco.

The model pathogen Ralstonia solanacearum GMI1000 is the causal agent of the bacterial wilt disease that attacks many solanaceous plants and other hosts but not tobacco (Nicotiana spp.). We found that two type III secretion system effector genes, avrA and popP1, are limiting the host range of strain GMI1000 on at least three tobacco species (N. tabacum, N. benthamiana, and N. glutinosa). Both effectors elicit the hypersensitive response (HR) on these tobacco species, although in different manners; AvrA is the major determinant recognized by N. tabacum and N. benthamiana, while PopP1 appears to be the major HR elicitor on N. glutinosa. Only the double inactivation of the avrA and popP1 genes allowed GMI1000 to wilt tobacco plants, thus showing that GMI1000 intrinsically possesses the functions necessary to wilt tobacco plants. A focused analysis on AvrA revealed that the first 58 N-terminal amino acids are sufficient to direct its injection into plant cells. We identified a hypervariable region in avrA, which contains variable numbers of tandem repeats (VNTR), each composed of 12 base pairs. We show that an 18-amino acid region in which the VNTR insertion occurs is an important domain involved in HR elicitation on N. benthamiana. avrA appears to be the target of various DNA insertions or mobile elements that probably allow R. solanacearum to evade the recognition and defense responses of tobacco.