Non-classic cystic fibrosis associated with D1152H CFTR mutation

BACKGROUND

Limited knowledge exists on phenotypes associated with the D1152H cystic fibrosis transmembrane conductance regulator (CFTR) mutation.

METHODS

Subjects with a D1152H allele in trans with another CFTR mutation were identified using the French Cystic Fibrosis Registry. Phenotypic characteristics were compared with those of pancreatic insufficient (PI) and pancreatic sufficient (PS) cystic fibrosis (CF) subjects in the Registry (CF cohort).

RESULTS

Forty-two subjects with D1152H alleles were identified. Features leading to diagnosis included chronic sinopulmonary disease (n = 25), congenital absence of the vas deferens (n = 11), systematic neonatal screening (n = 4), and genetic counseling (n = 2). Median age at diagnosis was 33 [interquartile range (IQR, 24-41)] years in D1152H subjects. Median sweat chloride concentrations were 43.5 (39-63) mmol/l in D1152H subjects and were markedly lower than in PI and PS CF subjects (p < 0.05). Bronchiectasis was present in 67% of D1152H subjects, but Pseudomonas aeruginosa colonization and pancreatic insufficiency were present in <30% of subjects. Estimated rates of decline in forced expiratory volume in 1 s (FEV(1)) were lower in D1152H subjects vs PI CF subjects (p < 0.05). None of the D1152H subjects identified since 1999 had died or required lung transplantation.

CONCLUSIONS

When present in trans with a CF-causing mutation, D1152H causes significant pulmonary disease, but all subjects had prolonged survival.

[Long QT syndrome: an underestimated cause of sudden infant death]

Congenital long QT syndrome (LQTS) is an inherited arrhythmia that can be sporadic or familial. It predisposes to sudden cardiac death by ventricular fibrillation, which can occur at any age, particularly in neonates. Recent postmortem molecular screening surveys have shown that 10 to 12% of sudden infant death syndrome (SIDS) cases were potentially related to congenital long QT syndrome. Current SIDS etiological surveys fail to diagnose LQTS. Specific questioning and electrocardiographic screening of first-degree relatives could greatly facilitate LQTS diagnosis. We propose adding these to screening modalities after a SIDS incident. Neonatal electrocardiographic screening could allow early identification of LQTS and adapted treatment and follow-up.

[The French nationwide cystic fibrosis newborn screening program: strategy and results]

In 2002 France implemented a nationwide newborn screening program for cystic fibrosis (CF). The strategy combined immunoreactive trypsinogen and, in case of a value over the cut-off level, DNA analysis in dried blood samples at day 3. Data were centralized and periodically analyzed thus maintaining the percentage of samples requiring mutation analysis (0.6%), limiting the number of false-positive cases (0.1%) without increasing the number of false-negative cases (3.2%). 3.527.353 infants were screened between 2002 and 2006. The overall cystic fibrosis incidence was 1/ 4136 with a wide range of regional variations. Dilemma case presentation occurred for 14 % of the patients; an European working group is actively working on this topic, attempting to establish a consensus on the adequate procedures. Cystic fibrosis newborn screening is feasible all over a nation but needs a strong organization from maternity wards to CF care centers.

Near- and far-field verification of electro-optic effect enhancement on a tunable lithium niobate photonic crystal

In this paper, we present the optical response of a tunable lithium niobate photonic crystal (PC) using the electro-optic effect of the material. The band gap tunability is 300 times higher than what one could expect for a bulk lithium niobate device of the same characteristics. Theoretical calculations based on the finite-difference time domain technique have allowed us to determine the physical origin of this enhanced electro-optic coefficient. Indeed, the effective second-order susceptibility in the LN nanostructure increases, giving rise to an ultra-compact low-voltage photonic crystal modulator when it operates at its band edge. In addition, the theoretical and far-field transmission results are confirmed by near-field optical microscopy images of the structure at different excitation voltages.

Neonatal screening of cystic fibrosis: diagnostic problems with CFTR mild mutations

Newborn screening (NBS) of cystic fibrosis (CF) was implemented throughout the whole of France in 2002, but it had been established earlier in three western French regions. It can reveal atypical CF with one or two known CFTR mild mutations, with an uncertain evolution. The sweat test can be normal or borderline. In Brittany, from 1989 to 2004, 196 CF cases were diagnosed (1/2885 births). The incidence of atypical CF diagnosed by NBS is 9.7% (19 from 196). The outcome of 17 (2 lost of view) has been studied, with 9 other atypical CF cases diagnosed by NBS in two other regions. The follow-up period extends from 0.25 to 19.8 years (NBS implemented in Normandy in 1980) with mean age 4.6 years. The most frequent mild mutation is R117H ISV8-7T (50%). At the time of the last visit, nutritional status is normal. All these CF patients are pancreatic sufficient. Only one patient exhibits respiratory infections, whereas 7 others have them intermittently. Two of them had intermittent Pseudomonas aeruginosa colonization at 2.8 and 6.5 years. Mean Shwachman score is 96.7, mean Brasfield score is 22.8. Eight children have had lung function tests (mean follow-up of 10 years): mean FVC was 99% of predicted, mean FEV1 101%, but one of them has FEV1 of 48%. Predicting the phenotype of these atypical CF patients remains difficult, thus complicating any genetic counselling. A regular clinical evaluation is necessary, if possible by a CF unit, because CF symptoms may appear later.

Évolution des épreuves fonctionnelles respiratoires (EFR) chez des enfants atteints de mucoviscidose et dépistés à la naissance. Lien avec l'infection pulmonaire. Étude sur 40 enfants et 744 EFR

OBJECTIVES

To report longitudinal assessment of pulmonary function in children with neonatal screening for cystic fibrosis and its relationships with Pseudomonas aeruginosa (PA) chronic infection, nutritional status, sex, age and genotype.

POPULATION AND METHODS

Children benefited systematically of 3 visits a year with pulmonary function tests (PFT) and bacteriological examination. Forty children and 744 PFTs were analysed, with 38 children during at least 4 years.

RESULTS

We reported a decrease of pulmonary function tests with chronic PA infection and the genotype DeltaF508/DeltaF508. The decline was gradual and not different between not infected and recently infected children. The PFTs of children infected for a long times were very deteriorate, probably due to the fact that they were infected with multiresistant strains of PA.

CONCLUSION

We think that it is important to survey pulmonary function before 5 years old in these early infected children. We should determinate if the important decrease of PFT in these early infected children is due to infection by PA mucoid.

Combining immunoreactive trypsinogen and pancreatitis-associated protein assays, a method of newborn screening for cystic fibrosis that avoids DNA analysis

OBJECTIVES

To evaluate the performance of a strategy in which, after immunoreactive trypsinogen (IRT) determination, genetic analysis is replaced by a biological test, the pancreatitis-associated protein (PAP) enzyme-linked immunosorbent assay (ELISA).

STUDY DESIGN

The French newborn screening program includes cystic fibrosis (CF) screening by the IRT/CFTR mutation strategy. PAP was assayed on screening cards, in parallel with IRT, in all newborns from 5 French regions (n = 204,749). Analysis of PAP values in CF and non-CF newborns with elevated IRT allowed direct comparison between the current strategy and the proposed IRT/PAP strategy.

RESULTS

A protocol in which newborns with IRT >50 ng/mL and PAP >1.8 ng/mL and those with IRT >100 ng/mL and PAP >1.0 ng/mL are directly recalled for sweat testing would have the same performance as the IRT/CFTR mutation strategy.

CONCLUSIONS

The IRT/PAP strategy is an alternative for CF newborn screening, which avoids the drawbacks of genetic analysis and is cheaper and easier to implement than the current IRT/CFTR mutation strategy.