Respiratory distress syndrome due to a novel homozygous ABCA3 mutation in a term neonate

[Dyspnea and ventilator dependence after birth in a full-term female infant]

A female infant, aged 43 days, had shortness of breath, cyanosis, groan, and dyspnea since birth. Physical examination showed cyanosis of lips and three-concave sign, and multiple lung imaging examinations showed diffuse ground-glass opacities in both lungs. The girl was given anti-infective therapy and continuous mechanical ventilation but there were no significant improvements in symptoms. Gene testing confirmed a compound heterozygous mutation, c.1890C>A(p.Tyr630Ter)+c.3208G>A(p.Ala1070Thr), in the ABCA3 gene, with the former from her father and the latter from her mother. Pathological examination of the lungs indicated pulmonary interstitial disease. The girl was diagnosed with infantile diffuse pulmonary interstitial disease caused by mutations in the ABCA3 gene. When full-term neonates experience shortness of breath and dyspnea after birth, pulmonary imaging suggests diffuse ground-glass changes, and conventional treatment is not effective (ventilator-dependent), congenital pulmonary surfactant metabolism defects needs to be considered. Gene testing, which can provide a basis for early intervention, prognostic evaluation, and genetic counseling, should be performed as early as possible.

[Dyspnea and ventilator dependence after birth in a full-term female infant]

A female infant, aged 43 days, had shortness of breath, cyanosis, groan, and dyspnea since birth. Physical examination showed cyanosis of lips and three-concave sign, and multiple lung imaging examinations showed diffuse ground-glass opacities in both lungs. The girl was given anti-infective therapy and continuous mechanical ventilation but there were no significant improvements in symptoms. Gene testing confirmed a compound heterozygous mutation, c.1890C>A(p.Tyr630Ter)+c.3208G>A(p.Ala1070Thr), in the ABCA3 gene, with the former from her father and the latter from her mother. Pathological examination of the lungs indicated pulmonary interstitial disease. The girl was diagnosed with infantile diffuse pulmonary interstitial disease caused by mutations in the ABCA3 gene. When full-term neonates experience shortness of breath and dyspnea after birth, pulmonary imaging suggests diffuse ground-glass changes, and conventional treatment is not effective (ventilator-dependent), congenital pulmonary surfactant metabolism defects needs to be considered. Gene testing, which can provide a basis for early intervention, prognostic evaluation, and genetic counseling, should be performed as early as possible.

Lung disease caused by ABCA3 mutations

BACKGROUND

Knowledge about the clinical spectrum of lung disease caused by variations in the ATP binding cassette subfamily A member 3 (ABCA3) gene is limited. Here we describe genotype-phenotype correlations in a European cohort.

METHODS

We retrospectively analysed baseline and outcome characteristics of 40 patients with two disease-causing ABCA3 mutations collected between 2001 and 2015.

RESULTS

Of 22 homozygous (15 male) and 18 compound heterozygous patients (3 male), 37 presented with neonatal respiratory distress syndrome as term babies. At follow-up, two major phenotypes are documented: patients with (1) early lethal mutations subdivided into (1a) dying within the first 6 months or (1b) before the age of 5 years, and (2) patients with prolonged survival into childhood, adolescence or adulthood. Patients with null/null mutations predicting complete ABCA3 deficiency died within the 1st weeks to months of life, while those with null/other or other/other mutations had a more variable presentation and outcome. Treatment with exogenous surfactant, systemic steroids, hydroxychloroquine and whole lung lavages had apparent but many times transient effects in individual subjects.

CONCLUSIONS

Overall long-term (>5 years) survival of subjects with two disease-causing ABCA3 mutations was <20%. Response to therapies needs to be ascertained in randomised controlled trials.

Candidate genes of idiopathic pulmonary fibrosis: current evidence and research

Idiopathic pulmonary fibrosis (IPF) is a group of common and lethal forms of idiopathic interstitial pulmonary disease. IPF is characterized by a progressive decline in lung function with a median survival of 2-3 years after diagnosis. Although the pathogenesis of the disease remains unknown, genetic predisposition could play a causal role in IPF. A set of genes have been identified as candidate genes of IPF in the past 20 years. However, the recent technological advances that allow for the analysis of millions of polymorphisms in different subjects have deepened the understanding of the genetic complexity of IPF susceptibility. Genome-wide association studies and whole-genome sequencing continue to reveal the genetic loci associated with IPF risk. In this review, we describe candidate genes on the basis of their functions and aim to gain a better understanding of the genetic basis of IPF. The discovered candidate genes may help to clarify pivotal aspects in the diagnosis, prognosis, and therapies of IPF.

A large kindred of pulmonary fibrosis associated with a novel ABCA3 gene variant

Background

Interstitial lung disease occurring in children is a condition characterized by high frequency of cases due to genetic aberrations of pulmonary surfactant homeostasis, that are also believed to be responsible of a fraction of familial pulmonary fibrosis. To our knowledge, ABCA3 gene was not previously reported as causative agent of fibrosis affecting both children and adults in the same kindred.

Methods

We investigated a large kindred in which two members, a girl whose interstitial lung disease was first recognized at age of 13, and an adult, showed a diffuse pulmonary fibrosis with marked differences in terms of morphology and imaging. An additional, asymptomatic family member was detected by genetic analysis. Surfactant abnormalities were investigated at biochemical, and genetic level, as well as by cell transfection experiments.

Results

Bronchoalveolar lavage fluid analysis of the patients revealed absence of surfactant protein C, whereas the gene sequence was normal. By contrast, sequence of the ABCA3 gene showed a novel homozygous G > A transition at nucleotide 2891, localized within exon 21, resulting in a glycine to aspartic acid change at codon 964. Interestingly, the lung specimens from the girl displayed a morphologic usual interstitial pneumonitis-like pattern, whereas the specimens from one of the two adult patients showed rather a non specific interstitial pneumonitis-like pattern.

Conclusions

We have detected a large kindred with a novel ABCA3 mutation likely causing interstitial lung fibrosis affecting either young and adult family members. We suggest that ABCA3 gene should be considered in genetic testing in the occurrence of familial pulmonary fibrosis.