Gestational and neonatal characteristics of children with cystic fibrosis: a cohort study

Prevalence and Clinical Significance of Commonly Diagnosed Genetic Disorders in Preterm Infants

Background and Objectives

Preterm infants (<34 weeks' gestation) experience high rates of morbidity and mortality before hospital discharge. Genetic disorders substantially contribute to morbidity and mortality in related populations. The prevalence and clinical impact of genetic disorders is unknown in this population. We sought to determine the prevalence of commonly diagnosed genetic disorders in preterm infants, and to determine the association of disorders with morbidity and mortality.

Methods

This was a retrospective multicenter cohort study of infants born from 23 to 33 weeks' gestation between 2000 and 2020. Genetic disorders were abstracted from diagnoses present in electronic health records. We excluded infants transferred from or to other health care facilities prior to discharge or death when analyzing clinical outcomes. We determined the adjusted odds of pre-discharge morbidity or mortality after adjusting for known risk factors.

Results

Of 320,582 infants, 4196 (1.3%) had genetic disorders. Infants with trisomy 13, 18, 21, or cystic fibrosis had greater adjusted odds of severe morbidity or mortality. Of the 17,427 infants who died, 566 (3.2%) had genetic disorders. Of the 65,968 infants with a severe morbidity, 1319 (2.0%) had genetic disorders.ConclusionsGenetic disorders are prevalent in preterm infants, especially those with life-threatening morbidities. Clinicians should consider genetic testing for preterm infants with severe morbidity and maintain a higher index of suspicion for life-threatening morbidities in preterm infants with genetic disorders. Prospective genomic research is needed to clarify the prevalence of genetic disorders in this population, and the contribution of genetic disorders to preterm birth and subsequent morbidity and mortality.

Article Summary

Genetic disorders were found in 1.3% of preterm infants and at a higher rate (2.0%) in infants who died or developed severe morbidity.

What’s Known on This Subject

Previous research described the prevalence and associated short-term morbidity and mortality of trisomy 13, 18, and 21 in preterm infants. The prevalence of other commonly diagnosed genetic disorders and associated short-term morbidity and mortality in preterm infants is unknown.

What This Study Adds

In a multicenter, retrospective cohort of 320,582 preterm (<34 weeks' gestation) infants, we found that 1.3% had genetic disorders diagnosed through standard care. Multiple disorders were associated with increased adjusted odds of morbidities or mortality prior to hospital discharge.

Contributors Statement Page

Selin S. Everett conceptualized and designed the study, conducted analyses, drafted the initial manuscript, and critically reviewed and revised the manuscript.Dr. Thomas Hays conceptualized and designed the study, drafted the initial manuscript, and critically reviewed and revised the manuscript.Miles Bomback conceptualized and designed the study and critically reviewed and revised the manuscript.Drs. Veeral N. Tolia and Reese H. Clark coordinated and supervised data collection and critically reviewed and revised the manuscript.Dr. Rakesh Sahni conceptualized and designed the study and critically reviewed and revised the manuscript.Dr. Alex Lyford conducted analyses and critically reviewed and revised the manuscript. Dr. Ronald J. Wapner reviewed and critically revised the manuscript.All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.

Association of Maternal and Neonatal Birth Outcomes With Subsequent Pediatric Transplants

BACKGROUND

We identified maternal and neonatal birth characteristics that were associated with organ or tissue transplants during childhood.

METHODS

We designed a retrospective cohort study of the population of children born between 2006 and 2019 in Quebec, Canada. The exposure included birth complications such as congenital anomaly, neonatal blood transfusion, and oligohydramnios. The main outcome measure was organ or tissue transplantation before 14 y of age. We categorized transplants according to type (major organs versus superficial tissues). To determine the association of birth characteristics with risk of pediatric transplant, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox proportional hazards models adjusted for potential confounders.

RESULTS

The cohort comprised 1 038 375 children with 7 712 678 person-years of follow-up, including 436 children who had transplants before 14 y of age. Birth complications were predominantly associated with major organ transplants. Congenital anomaly was associated with heart or lung (HR, 10.41; 95% CI, 5.33-20.33) and kidney transplants (HR, 13.69; 95% CI, 7.48-25.06), compared with no anomaly. Neonatal blood transfusion was associated with all major organ transplants, compared with no transfusion. Maternal complications were not as strongly associated with the risk of childhood transplant, although oligohydramnios was associated with 16.84 times (95% CI, 8.09-35.02) the risk of kidney transplant, compared with no oligohydramnios.

CONCLUSIONS

Adverse birth outcomes such as congenital anomaly, neonatal blood transfusion, and maternal oligohydramnios are associated with a greater risk of transplantation before 14 y of age. Maternal and neonatal birth outcomes may be useful predictors of transplantation.

Resolution of severe hepatosteatosis in a cystic fibrosis patient with multifactorial choline deficiency: A case report

In cystic fibrosis (CF), 85% to 90% of patients develop exocrine pancreatic insufficiency. Despite enzyme substitution, low pancreatic phospholipase A2 (sPLaseA2-IB) activity causes fecal loss of bile phosphatidylcholine and choline deficiency. We report on a female patient who has CF and progressive hepatosteatosis from 4.5 y onward. At 22.3 y, the liver comprised 27% fat (2385 mL volume) and transaminases were strongly increased. Plasma choline was 1.9 µmol/L (normal: 8-12 mol/L). Supplementation with 3 ×  1g/d choline chloride decreased liver fat and volume (3 mo: 8.2%; 1912 mL) and normalized transaminases. Plasma choline increased to only 5.6 µmol/L upon supplementation, with high trimethylamine oxide levels (12-35 µmol/L; normal: 3 ± 1 mol/L) proving intestinal microbial choline degradation. The patient was homozygous for rs12325817, a frequent single-nucleotide polymorphism in the PEMT gene, associated with severe hepatosteatosis in response to choline deficiency. Resolution of steatosis required 2 y (4.5% fat). Discontinuation/resumption of choline supplementation resulted in rapid relapse/resolution of steatosis, increased transaminases, and abdominal pain.

Growth failure and treatment in cystic fibrosis

Poor growth has long been a characteristic feature of cystic fibrosis (CF) and is significantly linked to lung function and overall health status. Improvements in pulmonary and nutrition care for patients with cystic fibrosis (CF) have resulted in better growth outcomes; however, height gains have not paralleled the improvements in weight in children with CF, and patients with more severe CF mutations remain significantly more affected. Many factors affect the growth hormone-IGF-1 axis and the growth plate of the long bones, including the chronic inflammatory state associated with CF. There are also increasing data on the direct effects of CFTR on bone and implications for CFTR modulators in attaining optimal growth. Treatments aimed at improving growth in CF are also reviewed here.

Choline in cystic fibrosis: relations to pancreas insufficiency, enterohepatic cycle, PEMT and intestinal microbiota

BACKGROUND

Cystic Fibrosis (CF) is an autosomal recessive disorder with life-threatening organ manifestations. 87% of CF patients develop exocrine pancreas insufficiency, frequently starting in utero and requiring lifelong pancreatic enzyme substitution. 99% develop progressive lung disease, and 20-60% CF-related liver disease, from mild steatosis to cirrhosis. Characteristically, pancreas, liver and lung are linked by choline metabolism, a critical nutrient in CF. Choline is a tightly regulated tissue component in the form of phosphatidylcholine (Ptd'Cho) and sphingomyelin (SPH) in all membranes and many secretions, particularly of liver (bile, lipoproteins) and lung (surfactant, lipoproteins). Via its downstream metabolites, betaine, dimethylglycine and sarcosine, choline is the major one-carbon donor for methionine regeneration from homocysteine. Methionine is primarily used for essential methylation processes via S-adenosyl-methionine.

CLINICAL IMPACT

CF patients with exocrine pancreas insufficiency frequently develop choline deficiency, due to loss of bile Ptd'Cho via feces. ~ 50% (11-12 g) of hepatic Ptd'Cho is daily secreted into the duodenum. Its re-uptake requires cleavage to lyso-Ptd'Cho by pancreatic and small intestinal phospholipases requiring alkaline environment. Impaired CFTR-dependent bicarbonate secretion, however, results in low duodenal pH, impaired phospholipase activity, fecal Ptd'Cho loss and choline deficiency. Low plasma choline causes decreased availability for parenchymal Ptd'Cho metabolism, impacting on organ functions. Choline deficiency results in hepatic choline/Ptd'Cho accretion from lung tissue via high density lipoproteins, explaining the link between choline deficiency and lung function. Hepatic Ptd'Cho synthesis from phosphatidylethanolamine by phosphatidylethanolamine-N-methyltransferase (PEMT) partly compensates for choline deficiency, but frequent single nucleotide polymorphisms enhance choline requirement. Additionally, small intestinal bacterial overgrowth (SIBO) frequently causes intraluminal choline degradation in CF patients prior to its absorption. As adequate choline supplementation was clinically effective and adult as well as pediatric CF patients suffer from choline deficiency, choline supplementation in CF patients of all ages should be evaluated.

Predictive effects of low birth weight and small for gestational age status on respiratory and nutritional outcomes in cystic fibrosis

INTRODUCTION

Prior literature shows that neonates with cystic fibrosis (CF) are more likely to be born low birth weight (LBW, <2500 grams) and/or small for gestational age (SGA, <10^th percentile for weight) than non-CF counterparts. There is limited literature exploring the predictive effects of birth parameters on long-term outcomes.

METHODS

The study population (CF Twin and Sibling Study) was recruited between 2000-2013 (n = 1677). Relationships between FEV₁ percent predicted at 6, 12, or 18 years or BMI z-score at 2, 6, 12, or 18 years, and predictor variables (LBW or SGA status) were assessed using adjusted linear regressions.

RESULTS

Mean birth weight was 3.3 ± 0.7 kg (Females: 3.2 ± 0.7kg; males: 3.4 ± 0.7kg) and mean gestational age was 38.4 ± 2.6 weeks, with 10.2% of participants classified as SGA. Predictors of LBW included female sex, pancreatic insufficiency, and prematurity. Predictors of SGA included female sex. After adjustment, LBW was associated with lower BMI at ages 2-12 years and SGA was associated with lower BMI at age 2 years. LBW was associated with lower FEV₁ percent predicted only at age 6 years. SGA was not associated with FEV₁.

CONCLUSIONS

We did not observe higher rates of LBW or SGA in full term infants compared to the general population. We observed associations particularly between LBW and BMI or FEV₁, but these associations decreased with age, suggesting that alternate factors contribute to outcomes over time. In lieu of the ability to target growth during gestation, efforts could be considered to optimize infant nutritional status, which may improve later life outcomes.

Impact of cystic fibrosis on birthweight: a population based study of children in Denmark and Wales

BACKGROUND

Poor growth during infancy and childhood is a characteristic feature of cystic fibrosis (CF). However, the impact of CF on intrauterine growth is unclear. We studied the effect of CF on birth weight in Denmark and Wales, and assessed whether any associations are due to differences in gestational age at birth.

METHODS

We conducted national registry linkage studies in two countries, using data for 2.2 million singletons born in Denmark (between 1980 and 2010) and Wales (between 1998 and 2015). We used hospital inpatient and outpatient data to identify 852 children with CF. Using causal mediation methods, we estimated the direct and indirect (via gestational age) effect of CF on birth weight after adjustment for sex, parity and socioeconomic background. We tested the robustness of our results by adjusting for additional factors such as maternal smoking during pregnancy in subpopulations where these data were available.

RESULTS

Babies with CF were more likely to be born preterm and with low birth weight than babies with no CF (12.7% vs 5% and 9.4% vs 5.8% preterm; 11.9% vs 4.2% and 11% vs 5.4% low birth weight in Denmark and Wales, respectively). Using causal mediation methods, the total effect of CF on birth weight was estimated to be -178.8 g (95% CI -225.43 to -134.47 g) in the Danish population and -210.08 g (95% CI -281.97 to -141.5 g) in the Welsh population. About 40% of this effect of CF on birth weight was mediated through gestational age.

CONCLUSIONS

CF significantly impacts on intrauterine growth and leads to lower birth weight in babies with CF, which is only partially explained by shorter gestation.

Neonatal screening in the Czech Republic: increased prevalence of selected diseases in low birthweight neonates

Neonates with low birthweight (LBW) represent a vulnerable population. This retrospective study analyzed the birth frequency of diseases detected by neonatal screening (NBS) in normal and LBW neonates in the Czech Republic. Between years 2002 and 2016, the number of screened disorders in the Czech Republic gradually increased from two to 13. Prevalence of screened diseases was calculated for cohorts ranging from 777,100 to 1,277,283 neonates stratified by birthweight. Odds ratio of the association of LBW with each disease was calculated and statistical significance was evaluated using the chi-square test or Fisher's exact test, as appropriate. Three diseases were associated with higher risk of prevalence in LBW neonates, namely congenital hypothyroidism (OR 2.50, CI 1.92; 3.25), cystic fibrosis (OR 2.44, CI 1.51; 3.94), and long chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) (OR 7.74, CI 2.18; 27.42).Conclusion: Although the underlying mechanisms are not well understood, results can be hypothesized that LBW (respectively prematurity) may lead to the secondary and often transitory hypothyroidism while cystic fibrosis and LCHADD may manifest already prenatally and result into preterm birth and LBW. What is Known: • The percentage of low birthweight (LBW) neonates in the Czech Republic has been increasing. • Previously published studies reported positive association between LBW and congenital hypothyroidism and cystic fibrosis. What is New: • The association between LCHADD and LBW has not yet been described. • LBW can be the first manifestation of cystic fibrosis and LCHADD.

Common clinical features of CF (respiratory disease and exocrine pancreatic insufficiency)

First described as a disease of the pancreas, cystic fibrosis is a genetically inherited progressive disease affecting multiple organ systems. Pulmonary and pancreatic involvement is common in individuals with cystic fibrosis, and the former is attributable to most of the mortality that occurs with the condition. This chapter provides an overview of a clinical approach to the pulmonary and pancreatic manifestations of cystic fibrosis.

Growth deficits in cystic fibrosis mice begin in utero prior to IGF-1 reduction

Growth deficits are common in cystic fibrosis (CF), but their cause is complex, with contributions from exocrine pancreatic insufficiency, pulmonary complications, gastrointestinal obstructions, and endocrine abnormalities. The CF mouse model displays similar growth impairment despite exocrine pancreatic function and in the absence of chronic pulmonary infection. The high incidence of intestinal obstruction in the CF mouse has been suggested to significantly contribute to the observed growth deficits. Previous studies by our group have shown that restoration of the cystic fibrosis transmembrane conductance regulator (CFTR) in the intestinal epithelium prevents intestinal obstruction but does not improve growth. In this study, we further investigate growth deficits in CF and gut-corrected CF mice by assessing insulin-like growth factor 1 (IGF-1). IGF-1 levels were significantly decreased in CF and gut-corrected CF adult mice compared to wildtype littermates and were highly correlated with weight. Interestingly, perinatal IGF-1 levels were not significantly different between CF and wildtype littermates, even though growth deficits in CF mice could be detected late in gestation. Since CFTR has been suggested to play a role in water and nutrient exchange in the placenta through its interaction with aquaporins, we analyzed placental aquaporin expression in late-gestation CF and control littermates. While significant differences were observed in Aquaporin 9 expression in CF placentas in late gestation, there was no evidence of placental fluid exchange differences between CF and control littermates. The results from this study indicate that decreased IGF-1 levels are highly correlated with growth in CF mice, independent of CF intestinal obstruction. However, the perinatal growth deficits that are observed in CF mice are not due to decreased IGF-1 levels or differences in placenta-mediated fluid exchange. Further investigation is necessary to understand the etiology of early growth deficits in CF, as growth has been shown to be a significant factor in disease outcomes.

Cystic Fibrosis is Associated with Adverse Neonatal Outcomes in Washington State, 1996-2013

OBJECTIVE

To determine whether cystic fibrosis (CF) is associated with adverse neonatal outcomes in a recent birth cohort in the US.

STUDY DESIGN

A retrospective matched cohort study of infants born in Washington State from 1996 to 2013 was identified through birth certificate data and linked to statewide hospital discharge data. Infants with CF were identified by hospitalization (through age 5 years) in which a CF-specific International Classification of Diseases, Ninth Revision code was recorded. "Unexposed" infants lacked CF-related International Classification of Diseases, Ninth Revision codes and were randomly selected among births, frequency-matched to "exposed" infants on birth year. Associations of CF with adverse neonatal outcomes (low birth weight [LBW], small for gestational age [SGA], preterm birth, and infant mortality) were estimated through Poisson regression. We performed extreme value imputation to address possible ascertainment bias.

RESULTS

We identified 170 infants with CF and 3400 unexposed infants. CF was associated with increased relative risk (95% CI) of 3.5 (2.5-4.9), 1.6 (1.1-2.4), 3.0 (2.2-4.0), and 6.8 (1.7-26.5) for LBW, SGA, preterm birth, and infant death, respectively. The estimated relative risks were similar among infants born from 2006 to 2013, except SGA was no longer associated with CF diagnosis. Results were robust to extreme value imputation and exclusion of infants with meconium ileus.

CONCLUSIONS

Observed associations of CF with LBW, preterm birth, and infant death are unlikely to be due to ascertainment bias. Further work is needed to determine how to prevent these adverse neonatal outcomes.

Endocrine Disorders in Cystic Fibrosis

Cystic fibrosis is frequently complicated by endocrine disorders. Diabetes can be expected to affect most with CF and pancreatic insufficiency and varies widely in age of onset, but early identification and treatment improve morbidity and mortality. Short stature can be exacerbated by relative delay of puberty and by use of inhaled corticosteroids. Bone disease in CF causes fragility fractures and should be assessed by monitoring bone mineral density and optimizing vitamin D status. Detecting and managing endocrine complications in CF can reduce morbidity and mortality in CF. These complications can be expected to become more common as the CF population ages.

Growth Deficiency in Cystic Fibrosis Is Observable at Birth and Predictive of Early Pulmonary Function

INTRODUCTION

Cystic fibrosis (CF) is a complex disease that includes both pulmonary and gastrointestinal challenges, resulting in decreased weight. Pulmonary symptoms of CF are extremely variable. Greater body mass at an early age is associated with improved pulmonary function, but it is unknown at what age weight becomes predictive of pulmonary disease severity. The purpose of this study was to investigate the relationship between birth weight and pulmonary function in CF.

METHODS

Birth weight and pulmonary data were obtained. Linear regressions were used to examine the relationship between these two variables. A one-tailed t-test was used to compare birth weights between CF patients and the national average.

RESULTS

Birth weight was significantly lower in babies with CF and correlated with pulmonary disease at ages 6 and 10 years but not with age at which Pseudomonas aeruginosa colonization was observed.

DISCUSSION

These data suggest that CF growth deficiency has prenatal origins. Early nutritional intervention for babies with CF and a low birth weight is warranted to maximize pulmonary potential.

Bone disease in cystic fibrosis: new pathogenic insights opening novel therapies

Mutations within the gene encoding for the chloride ion channel cystic fibrosis transmembrane conductance regulator (CFTR) results in cystic fibrosis (CF), the most common lethal autosomal recessive genetic disease that causes a number of long-term health problems, as the bone disease. Osteoporosis and increased vertebral fracture risk associated with CF disease are becoming more important as the life expectancy of patients continues to improve. The etiology of low bone density is multifactorial, most probably a combination of inadequate peak bone mass during puberty and increased bone losses in adults. Body mass index, male sex, advanced pulmonary disease, malnutrition and chronic therapies are established additional risk factors for CF-related bone disease (CFBD). Consistently, recent evidence has confirmed that CFTR plays a major role in the osteoprotegerin (OPG) and COX-2 metabolite prostaglandin E2 (PGE2) production, two key regulators in the bone formation and regeneration. Several others mechanisms were also recognized from animal and cell models contributing to malfunctions of osteoblast (cell that form bone) and indirectly of bone-resorpting osteoclasts. Understanding such mechanisms is crucial for the development of therapies in CFBD. Innovative therapeutic approaches using CFTR modulators such as C18 have recently shown in vitro capacity to enhance PGE2 production and normalized the RANKL-to-OPG ratio in human osteoblasts bearing the mutation F508del-CFTR and therefore potential clinical utility in CFBD. This review focuses on the recently identified pathogenic mechanisms leading to CFBD and potential future therapies for treating CFBD.

Growth and the Growth Hormone-Insulin Like Growth Factor 1 Axis in Children With Chronic Inflammation: Current Evidence, Gaps in Knowledge, and Future Directions

Growth failure is frequently encountered in children with chronic inflammatory conditions like juvenile idiopathic arthritis, inflammatory bowel disease, and cystic fibrosis. Delayed puberty and attenuated pubertal growth spurt are often seen during adolescence. The underlying inflammatory state mediated by proinflammatory cytokines, prolonged use of glucocorticoid, and suboptimal nutrition contribute to growth failure and pubertal abnormalities. These factors can impair growth by their effects on the GH-IGF axis and also directly at the level of the growth plate via alterations in chondrogenesis and local growth factor signaling. Recent studies on the impact of cytokines and glucocorticoid on the growth plate further advanced our understanding of growth failure in chronic disease and provided a biological rationale of growth promotion. Targeting cytokines using biological therapy may lead to improvement of growth in some of these children, but approximately one-third continue to grow slowly. There is increasing evidence that the use of relatively high-dose recombinant human GH may lead to partial catch-up growth in chronic inflammatory conditions, although long-term follow-up data are currently limited. In this review, we comprehensively review the growth abnormalities in children with juvenile idiopathic arthritis, inflammatory bowel disease, and cystic fibrosis, systemic abnormalities of the GH-IGF axis, and growth plate perturbations. We also systematically reviewed all the current published studies of recombinant human GH in these conditions and discussed the role of recombinant human IGF-1.

Peripheral quantitative computed tomography (pQCT) bone measurements in children with cystic fibrosis

BACKGROUND

Individuals with cystic fibrosis (CF) have low bone density and increased fracture risk.

METHODS

Cross-sectional study investigating whole body bone mineral content (WBBMC), bone geometry and strength in 12 children with CF compared to 23 age- and sex-matched controls with and without adjusting for age, height, and body composition.

RESULTS

CF group had lower WBBMC than controls (P = 0.007) with larger differences at older ages (age-by-group, P = 0.08). CF group had decreased height (P = 0.006), a trend of lower lean mass per height (P = 0.08), and no difference in relationship between WBBMC and lean mass compared to controls (P = 0.65). Periosteal and endosteal circumferences were smaller in CF (each, P = 0.02). Positive relationships of cortical area and bone strength with age were attenuated with CF (group-by-age; each, P < 0.01).

CONCLUSION

Children with CF have similar WBBMC relative to lean mass as controls. Cortical bone area and bone strength were less in CF group compared to controls, with greater differences in older children.

[Factors impacting the growth and nutritional status of cystic fibrosis patients younger than 10 years of age who did not undergo neonatal screening]

OBJECTIVE

The aim of this study was to evaluate by clinical and laboratory parameters how cystic fibrosis (CF) affects growth and nutritional status of children who were undergoing CF treatment but did not receive newborn screening.

METHODS

A historical cohort study of 52 CF patients younger than 10 years of age were followed in a reference center in Campinas, Southeast Brazil. Anthropometric measurements were abstracted from medical records until March/2010, when neonatal screening program was implemented. Between September/2009 and March/2010, parental height of the 52 CF patients were also measured.

RESULTS

Regarding nutritional status, four patients had Z-scores ≤ -2 for height/age (H/A) and body mass index/age (BMI/A). The following variables were associated with improved H/A ratio: fewer hospitalizations, longer time from first appointment to diagnosis, longer time from birth to diagnosis and later onset of respiratory disease. Forced vital capacity [FVC(%)], forced expiratory flow between 25-75% of FVC [FEF25-75(%)], forced expiratory volume in the first second [FEV1(%)], gestational age, birth weight and early respiratory symptoms were associated with IMC/A.

CONCLUSIONS

Greater number of hospitalizations, diagnosis delay and early onset of respiratory disease had a negative impact on growth. Lower spirometric values, lower gestational age, lower birth weight, and early onset of respiratory symptoms had negative impact on nutritional status. Malnutrition was observed in 7.7% of cases, but 23% of children had nutritional risk.

Growth retardation and reduced growth hormone secretion in cystic fibrosis. Clinical observations from three CF centers

OBJECTIVE

Growth delay in cystic fibrosis is frequent and is usually the result of several interacting causes. It most often derives from severe respiratory impairment and severe malabsorption. There are however patients whose clinical condition is not severe enough to be held accountable for this phenomenon. We aimed at describing patients who showed growth delay, who were not affected by severe pulmonary disease or malabsorption and who, when tested, showed a reduced GH secretion after stimulation with conventional agents. We noticed a disproportionately large prevalence of growth hormone (GH) release deficit (GHRD) in pediatric cystic fibrosis (CF) patients.

PATIENTS AND METHODS

We examined all patients under our care in the period 2006-11, who were older than 5 and younger than 16 years old. We focussed on those who fell below the 3rd height percentile, or whose growth during the previous 18 months faltered by >2SD, and who did not present clinical conditions that could reasonably explain their failure to thrive. These patients were subjected to standard GH provocative tests.

RESULTS

Out of 285 who matched the age criterion, 33 patients also matched the height percentile criterion. While 15/33 suffered clinical conditions that could reasonably explain their failure to thrive, 18/33 underwent GH release provocative tests and 12/18 showed a release deficit.

CONCLUSIONS

We conclude that impaired GH secretion is more frequent among CF patients compared to the prevalence of GH deficiency in the general population and that GH release impairment may be an independent cause of growth delay in CF. Our findings are in agreement with recent studies that have described low GH levels in CF piglets and in neonates with CF [1].

Cystic fibrosis in premature infants

There are few reports of cystic fibrosis (CF) diagnosed in premature infants. We describe the clinical course of three patients, from our neonatal intensive care units, who were diagnosed with CF, and discuss the existing literature and treatment considerations.

Cystic fibrosis transmembrane conductance regulator with a shortened R domain rescues the intestinal phenotype of CFTR-/- mice

Gene transfer could provide a novel therapeutic approach for cystic fibrosis (CF), and adeno-associated virus (AAV) is a promising vector. However, the packaging capacity of AAV limits inclusion of the full-length cystic fibrosis transmembrane conductance regulator (CFTR) cDNA together with other regulatory and structural elements. To overcome AAV size constraints, we recently developed a shortened CFTR missing the N-terminal portion of the R domain (residues 708-759, CFTRΔR) and found that it retained regulated anion channel activity in vitro. To test the hypothesis that CFTRΔR could correct in vivo defects, we generated CFTR(-/-) mice bearing a transgene with a fatty acid binding protein promoter driving expression of human CFTRΔR in the intestine (CFTR(-/-);TgΔR). We found that intestinal crypts of CFTR(-/-);TgΔR mice expressed CFTRΔR and the intestine appeared histologically similar to that of WT mice. Moreover, like full-length CFTR transgene, the CFTRΔR transgene produced CFTR Cl(-) currents and rescued the CFTR(-/-) intestinal phenotype. These results indicate that the N-terminal part of the CFTR R domain is dispensable for in vivo intestinal physiology. Thus, CFTRΔR may have utility for AAV-mediated gene transfer in CF.

Pigs and humans with cystic fibrosis have reduced insulin-like growth factor 1 (IGF1) levels at birth

People with cystic fibrosis (CF) exhibit growth defects. That observation has been attributed, in part, to decreased insulin-like growth factor 1 (IGF1) levels, and the reduction has been blamed on malnutrition and pulmonary inflammation. However, patients with CF already have a reduced weight at birth, a manifestation not likely secondary to poor nutrition or inflammation. We found that, like humans, CF pigs were smaller than non-CF littermates and had lower IGF1 levels. To better understand the basis of IGF1 reduction, we studied newborn pigs and found low IGF1 levels within 12 h of birth. Moreover, humerus length and bone mineral content were decreased, consistent with less IGF1 activity in utero. These findings led us to test newborn humans with CF, and we found that they also had reduced IGF1 levels. Discovering lower IGF1 levels in newborn pigs and humans indicates that the decrease is not solely a consequence of malnutrition or pulmonary inflammation and that loss of cystic fibrosis transmembrane conductance regulator function has a more direct effect. Consistent with this hypothesis, we discovered reduced growth hormone release in organotypic pituitary slice cultures of newborn CF pigs. These findings may explain the long-standing observation that CF newborns are smaller than non-CF babies and why some patients with good clinical status fail to reach their growth potential. The results also suggest that measuring IGF1 levels might be of value as a biomarker to predict disease severity or the response to therapeutics. Finally, they raise the possibility that IGF1 supplementation beginning in infancy might be beneficial in CF.

Incidence of cystic fibrosis in the Albanian population

BACKGROUND

Cystic fibrosis (CF) is the most common life-threatening genetic disease in the Western world. Its incidence varies between 1:4,000 and 1:2,500 among Europeans. No data are available on the incidence of CF among Albanians, mainly due to difficulties of the local health system.

GOALS

To estimate the incidence of CF and the prevalence of healthy carrier status among Albanian ethnic people; to evaluate the incidence of hypertrypsinaemia at birth among Albanian newborns.

METHODS

We used the database of the newborn screening of Tuscany, Italy for the period 1991-2005. Children born to both Albanian parents in Tuscany were identified and incidences were calculated.

RESULTS

The incidence of CF among Albanians (1/555, 99% CI: 1/2,980-1/306) was significantly higher than the rest of the Tuscan population (1/4,101, 99% CI: 1/5,564-1/3,248). The prevalence of CF carrier status among Albanians living in Tuscany is estimated to be 1/12 (99%CI 1/27-1/9) while in the rest of the Tuscan population it is 1/32 (99%CI 1/37-1/28). The incidence of hypertrypsinaemia at birth among Albanian newborns (1/55 99%CI: 1/74-1/44) was significantly higher than in the rest of the population (1/84, 99%CI 1/88-1/82).

CONCLUSION

The incidence of CF among Albanians is considerably higher than expected. Albanian people have a risk to give birth to children with CF higher than the rest of Europeans. The implementation of a newborn screening program in Albania, together with a CF follow up program is highly advisable.

Interactions between secondhand smoke and genes that affect cystic fibrosis lung disease

CONTEXT

Disease variation can be substantial even in conditions with a single gene etiology such as cystic fibrosis (CF). Simultaneously studying the effects of genes and environment may provide insight into the causes of variation.

OBJECTIVE

To determine whether secondhand smoke exposure is associated with lung function and other outcomes in individuals with CF, whether socioeconomic status affects the relationship between secondhand smoke exposure and lung disease severity, and whether specific gene-environment interactions influence the effect of secondhand smoke exposure on lung function.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective assessment of lung function, stratified by environmental and genetic factors. Data were collected by the US Cystic Fibrosis Twin and Sibling Study with missing data supplemented by the Cystic Fibrosis Foundation Data Registry. All participants were diagnosed with CF, were recruited between October 2000 and October 2006, and were primarily from the United States.

MAIN OUTCOME MEASURES

Disease-specific cross-sectional and longitudinal measures of lung function.

RESULTS

Of 812 participants with data on secondhand smoke in the home, 188 (23.2%) were exposed. Of 780 participants with data on active maternal smoking during gestation, 129 (16.5%) were exposed. Secondhand smoke exposure in the home was associated with significantly lower cross-sectional (9.8 percentile point decrease; P < .001) and longitudinal lung function (6.1 percentile point decrease; P = .007) compared with those not exposed. Regression analysis demonstrated that socioeconomic status did not confound the adverse effect of secondhand smoke exposure on lung function. Interaction between gene variants and secondhand smoke exposure resulted in significant percentile point decreases in lung function, namely in CFTR non-DeltaF508 homozygotes (12.8 percentile point decrease; P = .001), TGFbeta1-509 TT homozygotes (22.7 percentile point decrease; P = .006), and TGFbeta1 codon 10 CC homozygotes (20.3 percentile point decrease; P = .005).

CONCLUSIONS

Any exposure to secondhand smoke adversely affects both cross-sectional and longitudinal measures of lung function in individuals with CF. Variations in the gene that causes CF (CFTR) and a CF-modifier gene (TGFbeta1) amplify the negative effects of secondhand smoke exposure.