Respiratory distress in a 2-month-old infant: Is the primary cause cardiac, pulmonary or both?

Deficiency of filamin A in smooth muscle cells protects against hypoxia‑mediated pulmonary hypertension in mice

Filamin A (FLNA) is a high molecular weight cytoskeleton protein important for cell locomotion. A relationship between FLNA mutations and pulmonary arterial hypertension (PAH) has previously been reported; however, the detailed mechanism remains unclear. The present study aimed to explore the role of FLNA in vascular smooth muscle cells during the development of PAH. Smooth muscle cell (SMC)‑specific FLNA‑deficient mice were generated and the mice were then exposed to hypoxia for 28 days to build the mouse model of PAH. Human pulmonary arterial smooth muscle cells (PASMCs) were also cultured and transfected with FLNA small interfering RNA or overexpression plasmids to investigate the effects of FLNA on PASMC proliferation and migration. Notably, compared with control individuals, the expression levels of FLNA were increased in lung tissues from patients with PAH, and it was obviously expressed in the PASMCs of pulmonary arterioles. FLNA deficiency in SMCs attenuated hypoxia‑induced pulmonary hypertension and pulmonary vascular remodeling. In vitro studies suggested that absence of FLNA impaired PASMC proliferation and migration, and produced lower levels of phosphorylated (p)‑PAK‑1 and RAC1 activity. However, FLNA overexpression promoted PASMC proliferation and migration, and increased the expression levels of p‑PAK‑1 and RAC1 activity. The present study highlights the role of FLNA in pulmonary vascular remodeling; therefore, it could serve as a potential target for the treatment of PAH.

Heterogenous Disease Course and Long-Term Outcome of Children's Interstitial Lung Disease Related to Filamin A Gene Variants

Rationale: Variable disease course and outcomes have been reported in children's interstitial lung disease associated with FLNA (Filamin A gene) variants. Objectives: To further delineate long-term respiratory outcomes and identify potential contributing factors to severe disease course. Methods: We retrospectively collected longitudinal data from three centers on nine cases (one male) with FLNA variants and early respiratory disease onset (within the first 24 mo of life). Clinical, radiographic, and histopathologic data were analyzed, focusing on cardiorespiratory disease course. Results: All required early respiratory support (three invasive ventilation, three noninvasive ventilation, three supplemental oxygen), and all experienced frequent severe infective respiratory exacerbations. Three died in infancy from refractory respiratory failure and pulmonary hypertension (PH). The six surviving individuals were 3, 10, 11, 15, 18, and 33 years old at time of reporting. The extent of functional respiratory impairment decreased with age; at last follow-up, there were no individuals on home invasive ventilation, one on nocturnal noninvasive ventilation, four on oxygen, and one on no respiratory support. Spirometry consistently demonstrated moderate to severe obstructive defects (forced expiratory volume in 1 s/forced vital capacity [FVC] z-score, -3.76 to -1.77; percent predicted FVC, 31.5% to 92.1%). Seven required PH treatment in early childhood (7/9), and three of the survivors (3/6) still receive treatment. Radiologic and histopathologic findings were consistent among cases. Conclusions: Early mortality was common, but many survivors stabilized even after severe symptoms in infancy. All survivors had persistent obstructive defects on spirometry, and half have persistent or recurrent PH. These typical findings are suggestive of this rare diagnosis and should prompt consideration of genetic testing.

Newborn Periventricular Nodular Heterotopia with Persistent Feeding Cyanosis and Apneic Spell: A Case Report

Periventricular nodular heterotopia (PNH) is a neuronal migration disorder that occurs during early brain development. Patients with PNH may be asymptomatic and have normal intelligence; however, PNH is also known to cause various symptoms such as seizures, dyslexia, and cardiovascular anomalies. PNH is not commonly diagnosed during early infancy because of the lack of clinical manifestations during this period. We present the case of a female infant diagnosed with PNH based on brain magnetic resonance imaging, who had symptomatic patent ductus arteriosus that had to be ligated surgically and had prolonged feeding cyanosis with frequent apneic spells.

Heterogeneous Pulmonary Phenotypes in Filamin A Mutation-Related Lung Disease

Background: Interstitial lung disease (ILD) has been recently reported in a few patients with pathogenic variants in the Filamin A (FLNA) gene with variable presentation and prognosis. This study evaluated the respiratory manifestations and clinical features in children with FLNA disease. Methods: We conducted a retrospective review of pediatric patients with variants in FLNA in a tertiary children's hospital. The clinical features, genotype, management, and outcomes were analyzed. Results: We identified 9 patients with variants in FLNA aged 15 months to 24 years, 4 females and 5 males. Six patients had abnormal chest imaging ranging from mild interstitial prominence to atelectasis, interstitial densities, and hyperinflation. Three patients with ILD presented during the neonatal period or early infancy with respiratory distress or respiratory failure requiring supplemental oxygen or assisted ventilation via tracheostomy. We report male twins with the same FLNA variant and lung disease, but different ages and clinical features at presentation eventually culminating in respiratory failure requiring assisted ventilation. All patients had FLNA variants identified by FLNA sequencing, had abnormal echocardiograms, and none of the patients underwent lung biopsy or lung transplantation. The outcomes were variable and could be as severe as chronic respiratory failure. Conclusion: The wide spectrum of respiratory manifestations and abnormal chest imaging in our study highlights the importance of evaluation for lung disease in patients with variants in FLNA. FLNA sequencing in suspected cases with ILD may obviate the need for a lung biopsy, prompt surveillance for progressive lung disease, and evaluation for associated clinical features.

Where the congenital heart disease meets the pulmonary arterial hypertension, FLNA matters: a case report and literature review

Background

Pediatric patients with genetic disorders have a higher incidence of pulmonary arterial hypertension (PAH) regardless of their heart defects. Filamin A (FLNA) mutation is recently recognized to be associated with pediatric pulmonary disorders, however, the clinical courses of PAH related to the mutation were reported in limited cases. Here, we presented a case and pooled data for better understanding of the correlation between FLNA mutation and pediatric PAH.

Case presentation

The patient was a 8-month-old female with repeated episodes of pneumonia. Physical examination revealed cleft lip, cleft palate and developmental retardation. Imaging examination showed a small atrial septal defect (ASD), central pulmonary artery enlargement, left upper lobe of lung atelectasis, and pulmonary infiltration. Genetic test showed she carried a de novo pathogenic variant of FLNA gene (c.5417-1G > A, p.-). Oral medications didn’t slow the progression of PAH in the patient, and she died two years later.

Conclusions

FLNA mutation causes rare but progressive PAH in addition to a wide spectrum of congenital heart disease and other comorbidities in pediatric patients. We highly recommend genetic testing for pediatric patients when suspected with PAH. Given the high mortality in this group, lung transplantation may offer a better outcome.

Congenital emphysematous lung disease associated with a novel Filamin A mutation. Case report and literature review

BACKGROUND

Progressive lung involvement in Filamin A (FLNA)-related cerebral periventricular nodular heterotopia (PVNH) has been reported in a limited number of cases.

CASE PRESENTATION

We report a new pathogenic FLNA gene variant (c.7391_7403del; p.Val2464Alafs*5) in a male infant who developed progressive lung disease with emphysematous lesions and interstitial involvement. Following lobar resection, chronic respiratory failure ensued necessitating continuous mechanical ventilation and tracheostomy. Cerebral periventricular nodular heterotopia was also present.

CONCLUSIONS

We report a novel variant of the FLNA gene, associated with a severe lung disorder and PNVH. The lung disorder led to respiratory failure during infancy and these pulmonary complications may be the first sign of this disorder. Early recognition with thoracic imaging is important to guide genetic testing, neuroimaging and to define optimal timing of potential therapies, such as lung transplant in progressive lung disease.