Congenital cutis laxa with a dominant inheritance and early onset emphysema

The first Japanese case of autosomal dominant cutis laxa with a frameshift mutation in exon 30 of the elastin gene complicated by small airway disease with 8 years of follow-up

BACKGROUND

Cutis laxa constitutes a diverse group of connective tissue diseases, both inherited and acquired, characterized by loose skin and varying systemic involvement, including pulmonary lesions. While cutis laxa has been linked to conditions like emphysema, asthma, and bronchiectasis, the specific pathological and radiological characteristics underlying pulmonary complications related to cutis laxa remain unclear.

CASE PRESENTATION

A 36-year-old woman, diagnosed with cutis laxa at birth, presented to our outpatient clinic with severe obstructive ventilatory impairment, evident in pulmonary function tests (expiratory volume in one second (FEV1)/forced vital capacity (FVC): 34.85%; %residual volume [RV]: 186.5%; %total lung capacity [TLC]: 129.2%). Pulmonary function tests also indicated small airway disease (%FEF50%, 7.9%; %FEF75%, 5.7%; and %FEF25-75%, 6.8%). Computed tomography (CT) revealed the lack of normal increase in lung attenuation on expiratory CT scan, with no discernible emphysematous changes. Exome sequencing was performed to confirm the association between the pulmonary lesions and cutis laxa, revealing a frameshift variant in exon 30 of the elastin gene (ELN). Further analysis employing a parametric response map revealed a longitudinal increase in the percentage of functional small airway disease (fSAD) from 37.84% to 46.61% over the 8-year follow-up, despite the absence of overt changes in CT findings, specifically the lack of normal increase in lung attenuation on expiratory CT scan. Over the same follow-up interval, there was a modest reduction of 25.6 mL/year in FEV1 coupled with a significant increase in %RV. Pulmonary function test metrics, reflective of small airway disease, exhibited a continual decline; specifically, %FEF50%, %FEF75%, and %FEF25-75% diminished from 7.9% to 7.0%, 5.7% to 4.6%, and 6.8% to 5.4%, respectively.

CONCLUSIONS

This case highlighted an instance of autosomal dominant cutis laxa arising from a frameshift variant in exon 30 of ELN, accompanied by small airway disease. Comprehensive investigation, utilizing quantitative CT analysis, revealed a longitudinal increase in fSAD percentage with a mild reduction in FEV1. These findings indicate that elastin deficiency may not only diminish elastic fibers in the skin but also be implicated in small airway disease by impacting components of the extracellular matrix in the lungs.

Precision Approaches to Chronic Obstructive Pulmonary Disease Management

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. COPD heterogeneity has hampered progress in developing pharmacotherapies that affect disease progression. This issue can be addressed by precision medicine approaches, which focus on understanding an individual's disease risk, and tailoring management based on pathobiology, environmental exposures, and psychosocial issues. There is an urgent need to identify COPD patients at high risk for poor outcomes and to understand at a mechanistic level why certain individuals are at high risk. Genetics, omics, and network analytic techniques have started to dissect COPD heterogeneity and identify patients with specific pathobiology. Drug repurposing approaches based on biomarkers of specific inflammatory processes (i.e., type 2 inflammation) are promising. As larger data sets, additional omics, and new analytical approaches become available, there will be enormous opportunities to identify high-risk individuals and treat COPD patients based on their specific pathophysiological derangements. These approaches show great promise for risk stratification, early intervention, drug repurposing, and developing novel therapeutic approaches for COPD.

Emerging mechanisms of elastin transcriptional regulation

Elastin provides recoil to tissues that stretch such as the lung, blood vessels, and skin. It is deposited in a brief window starting in the prenatal period and extending to adolescence in vertebrates, and then slowly turns over. Elastin insufficiency is seen in conditions such as Williams-Beuren syndrome and elastin-related supravalvar aortic stenosis, which are associated with a range of vascular and connective tissue manifestations. Regulation of the elastin (ELN) gene occurs at multiple levels including promoter activation/inhibition, mRNA stability, interaction with microRNAs, and alternative splicing. However, these mechanisms are incompletely understood. Better understanding of the processes controlling ELN gene expression may improve medicine's ability to intervene in these rare conditions, as well as to replace age-associated losses by re-initiating elastin production. This review describes what is known about the ELN gene promoter structure, transcriptional regulation by cytokines and transcription factors, and posttranscriptional regulation via mRNA stability and micro-RNA and highlights new approaches that may influence regenerative medicine.

Ring Finger Protein 213 in Moyamoya Disease With Pulmonary Arterial Hypertension: A Mini-Review

Moyamoya disease (MMD), most often diagnosed in children and adolescents, is a chronic cerebrovascular disease characterized by progressive stenosis at the terminal portion of the internal carotid artery and an abnormal vascular network at the base of the brain. Recently, many investigators show a great interest in MMD with pulmonary arterial hypertension (PAH). Ring finger protein 213 (RNF213) is a major susceptibility gene for MMD and also has strong correlations with PAH. Therefore, this review encapsulates current cases of MMD with PAH and discusses MMD with PAH in the aspects of epidemiology, pathology, possible pathogenesis, clinical manifestations, diagnosis, and treatment.

Acquired Localized Cutis Laxa: A Case Report and the Role of Plastic Surgery

Cutis laxa is an uncommon connective tissue disorder affecting the elastin fibers leading to lax and pendulous skin and in generalized form can present with systemic involvement. Congenital cutis laxa is common in comparison to acquired cutis laxa and has varied inheritance patterns. Treatment is chiefly observation in congenital cutis laxa, and there is a paucity of literature on surgical management in acquired cutis laxa. We report a rare case of acquired localized cutis laxa with a review of literature on the role of plastic surgery in this condition.

A novel elastin gene frameshift mutation in a Russian family with cutis laxa: a case report

Background

Cutis laxa (CL) is a rare connective tissue disorder characterized by loose, redundant, inelastic and wrinkled skin. Patients develop a prematurely aged appearance. Inheritance can be autosomal dominant or autosomal recessive. The X-linked form is now classified in the group of copper transport diseases. Autosomal dominant CL is characterized by wrinkled, redundant and sagging, inelastic skin and in some cases is associated with internal organ involvement.

Case presentation

We report a familial case of autosomal dominant CL, which includes a 33-year-old woman and her 11-year-old son with dry, thin and wrinkled skin that appeared prematurely aged. No serious involvement of internal organs was found. In both patients, we identified novel heterozygous mutation c.2323delG (p.Ala775fs) in exon 34 of elastin transcript NM_001278939.1. Similar frameshift mutations in the last exons of elastin gene were previously reported in patients with autosomal dominant CL.

Conclusions

Our results show a novel frameshift mutation that was found in patients with cutis laxa. Exome sequencing is effective and useful technology for properly diagnosis of diseases with similar phenotype to ensure proper treatment is provided.

Elastin-driven genetic diseases

Elastic fibers provide recoil to tissues that undergo repeated deformation, such as blood vessels, lungs and skin. Composed of elastin and its accessory proteins, the fibers are produced within a restricted developmental window and are stable for decades. Their eventual breakdown is associated with a loss of tissue resiliency and aging. Rare alteration of the elastin (ELN) gene produces disease by impacting protein dosage (supravalvar aortic stenosis, Williams Beuren syndrome and Williams Beuren region duplication syndrome) and protein function (autosomal dominant cutis laxa). This review highlights aspects of the elastin molecule and its assembly process that contribute to human disease and also discusses potential therapies aimed at treating diseases of elastin insufficiency.

What do polymorphisms tell us about the mechanisms of COPD?

COPD (chronic obstructive pulmonary disease) is characterized by irreversible lung airflow obstruction. Cigarette smoke is the major risk factor for COPD development. However, only a minority number of smokers develop COPD, and there are substantial variations in lung function among smokers, suggesting that genetic determinants in COPD susceptibility. During the past decade, genome-wide association studies and exome sequencing have been instrumental to identify the genetic determinants of complex traits, including COPD. Focused studies have revealed mechanisms by which genetic variants contribute to COPD and have led to novel insights in COPD pathogenesis. Through functional investigations of causal variants in COPD, from the proteinase-antiproteinase theory to emerging roles of developmental pathways (such as Hedgehog and Wnt pathways) in COPD, we have greatly expanded our understanding on this complex pulmonary disease. In this review, we critically review functional investigations on roles of genetic polymorphisms in COPD, and discuss future challenges and opportunities in discovering novel mechanisms of functional variants.

Bridging Lung Development with Chronic Obstructive Pulmonary Disease. Relevance of Developmental Pathways in Chronic Obstructive Pulmonary Disease Pathogenesis

Chronic obstructive pulmonary disease (COPD) is characterized by chronic airflow limitation. This generic term encompasses emphysema and chronic bronchitis, two common conditions, each having distinct but also overlapping features. Recent epidemiological and experimental studies have challenged the traditional view that COPD is exclusively an adult disease occurring after years of inhalational insults to the lungs, pinpointing abnormalities or disruption of the pathways that control lung development as an important susceptibility factor for adult COPD. In addition, there is growing evidence that emphysema is not solely a destructive process because it is also characterized by a failure in cell and molecular maintenance programs necessary for proper lung development. This leads to the concept that tissue regeneration required stimulation of signaling pathways that normally operate during development. We undertook a review of the literature to outline the contribution of developmental insults and genes in the occurrence and pathogenesis of COPD, respectively.

Genetic susceptibility

Why only 20% of smokers develop clinically relevant chronic obstructive pulmonary disease (COPD) was a puzzle for many years. Now, epidemiologic studies point clearly toward a large heritable component. The combination of genome-wide association studies and candidate gene analysis is helping to identify those genetic variants responsible for an individual's susceptibility to developing COPD. In this review, the current data implicating specific loci and genes in the pathogenesis of COPD are examined.

Supravalvular aortic stenosis: elastin arteriopathy

Supravalvular aortic stenosis is a systemic elastin (ELN) arteriopathy that disproportionately affects the supravalvular aorta. ELN arteriopathy may be present in a nonsyndromic condition or in syndromic conditions such as Williams-Beuren syndrome. The anatomic findings include congenital narrowing of the lumen of the aorta and other arteries, such as branches of pulmonary or coronary arteries. Given the systemic nature of the disease, accurate evaluation is recommended to establish the degree and extent of vascular involvement and to plan appropriate interventions, which are indicated whenever hemodynamically significant stenoses occur. ELN arteriopathy is genetically heterogeneous and occurs as a consequence of haploinsufficiency of the ELN gene on chromosome 7q11.23, owing to either microdeletion of the entire chromosomal region or ELN point mutations. Interestingly, there is a prevalence of premature termination mutations resulting in null alleles among ELN point mutations. The identification of the genetic defect in patients with supravalvular aortic stenosis is essential for a definitive diagnosis, prognosis, and genetic counseling.

Oculoplastic approach to congenital cutis laxa syndrome

Cutis laxa is a rare congenital or acquired disorder of elastic tissue, characterized by loose skin with folds and multiple internal organ involvement, which may cause life-threatening complications. We present a patient with cutis laxa syndrome who had cross eyelids with esotropia. Bilateral lateral canthal tendon repositioning and bilateral medial rectus recession procedures were performed in a single session. The patient had acceptable eyelid and globe cosmesis after the procedure.

LEVEL OF EVIDENCE IV

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Analysis of exonic elastin variants in severe, early-onset chronic obstructive pulmonary disease

The destruction of elastic fibers has been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). Emphysema has been described in autosomal dominant cutis laxa, which can be caused by mutations in the elastin gene. Previously, a rare functional mutation in the terminal exon of elastin was found in a case of severe, early-onset COPD. To test the hypothesis that other similar elastin mutations may predispose to COPD, we screened 90 probands from the Boston Early-Onset COPD Study and 90 smoking control subjects from the Normative Aging Study for mutations in elastin exons using high-resolution DNA melt analysis followed by resequencing. Rare nonsynonymous single-nucleotide polymorphisms (SNPs) seen only in cases were examined for segregation with airflow obstruction within pedigrees. Common nonsynonymous SNPs were tested for association with COPD in a family-based analysis of 949 subjects from the Boston Early-Onset COPD Study, and in a case-control analysis in 389 COPD cases from the National Emphysema Treatment Trial and 472 control subjects from the Normative Aging Study. Of 28 elastin variants found, 3 were nonsynonymous SNPs found only in cases. The previously described Gly773Asp mutation was found in another proband. The other two SNPs did not clearly segregate with COPD within families. Two common nonsynonymous SNPs did not demonstrate significant associations in either a family-based or case-control analysis. Exonic SNPs in the elastin gene do not appear to be common risk factors for severe COPD.

National Emphysema Treatment Trial state of the art: genetics of emphysema

Although a hereditary contribution to emphysema has been long suspected, severe alpha1-antitrypsin deficiency remains the only conclusively proven genetic risk factor for chronic obstructive pulmonary disease (COPD). Recently, genome-wide linkage analysis has led to the identification of two promising candidate genes for COPD: TGFB1 and SERPINE2. Like multiple other COPD candidate gene associations, even these positionally identified genes have not been universally replicated across all studies. Differences in phenotype definition may contribute to nonreplication in genetic studies of heterogeneous disorders such as COPD. The use of precisely measured phenotypes, including emphysema quantification on high-resolution chest computed tomography scans, has aided in the discovery of additional genes for clinically relevant COPD-related traits. The use of computed tomography scans to assess emphysema and airway disease as well as newer genetic technologies, including gene expression microarrays and genome-wide association studies, has great potential to detect novel genes affecting COPD susceptibility, severity, and response to treatment.

Collagen Vascular Diseases and Disorders of Connective Tissue

The collagen vascular diseases, also referred to as connective tissue diseases, are a diverse group of systemic inflammatory disorders thought to be immunologically mediated. The concept of collagen vascular disease began to take shape in the 1930s, when it was recognized that rheumatic fever and rheumatoid arthritis can affect connective tissues throughout the body.1,2 During the following decade, as conditions such as systemic lupus erythematosus (SLE) and scleroderma came to be viewed as systemic diseases of connective tissue, the terms diffuse connective disease and diffuse collagen disease were proposed.3,4 During the same period, the designation of diffuse vascular disease was proposed for diseases such as scleroderma, polymyositis, SLE, and polyarteritis nodosa, which featured widespread vascular involvement.5 With the realization that many of these entities can exhibit both systemic connective tissue manifestations and vascular abnormalities, the unifying designation of collagen vascular disease was introduced.6

Radiograma de tórax e tomografia computadorizada na avaliação do enfisema pulmonar

O enfisema é uma condição do pulmão, caracterizada pelo aumento acima do normal no tamanho dos espaços aéreos distais ao bronquíolo terminal. Atualmente, o enfisema é a quarta causa de morte nos EUA, afetando 14 milhões de pessoas. O presente artigo descreve as principais ferramentas no diagnóstico por imagem do enfisema, desde o início até os dias de hoje. Relata as técnicas tradicionais, como radiograma de tórax, e as evoluções no campo da tomografia computadorizada (TC), como a TC de alta resolução e a densitovolumetria pulmonar por TC tridimensional.

Progress in chronic obstructive pulmonary disease genetics

Familial aggregation of chronic obstructive pulmonary disease (COPD) has been demonstrated, suggesting that genetic factors likely influence the variable development of chronic airflow obstruction in response to smoking. A variety of approaches have been used to identify novel COPD susceptibility genes, including association studies, linkage analysis, and rare variant analysis. Future directions for COPD research include genomewide association studies and animal model genetic studies.

A functional mutation in the terminal exon of elastin in severe, early-onset chronic obstructive pulmonary disease

We describe a novel variant in the terminal exon of human elastin, c.2318 G > A, resulting in an amino acid substitution of glycine 773 to aspartate (G773D) in a pedigree with severe early-onset chronic obstructive pulmonary disease (COPD). Transfection studies with elastin cDNAs demonstrate that the glycine to aspartate change compromises the ability of the mutant protein to undergo normal elastin assembly. Other functional consequences of this amino acid substitution include altered proteolytic susceptibility of the C-terminal region of elastin and reduced interaction of the exon 36 sequence with matrix receptors on cells. These results suggest that the G773D variant confers structural and functional consequences relevant to the pathogenesis of COPD.

Autosomal dominant cutis laxa with severe lung disease: synthesis and matrix deposition of mutant tropoelastin

Cutis laxa (CL) is a heterogeneous group of genetic and acquired disorders with at least two autosomal dominant forms caused by mutations in the elastin and fibulin-5 genes, respectively. To define the molecular basis of CL in patients negative for point mutations in the elastin gene, metabolic labeling and immunoprecipitation experiments were used to study the synthesis of elastin in dermal fibroblasts. In addition to the normal 68 kDa tropoelastin (TE) protein, an abnormal, 120 kDa polypeptide was detected in the proband and her affected daughter in a CL family characterized by hernias and unusually severe and early-onset pulmonary disease including bronchiectasis and pulmonary emphysema. Mutational and gene expression studies established that affected individuals in this family carried a partial tandem duplication in the elastin locus. Immunoprecipitation experiments showed that the mutant TE was partially secreted and partially retained intracellularly. A polyclonal antibody raised against a unique peptide in the mutant TE molecule showed both intracellular and matrix staining. We conclude that elastin mutations can cause CL associated with a severe pulmonary phenotype. Synthesis of abnormal TE may interfere with elastic fiber function through a dominant-negative or a gain of function mechanism.

Splicing mutation in the fibrillin-1 gene associated with neonatal Marfan syndrome and severe pulmonary emphysema with tracheobronchomalacia

Neonatal Marfan syndrome is an autosomal-dominant connective tissue disease with unique clinical manifestations and mutations. We describe the clinical course of an infant with neonatal Marfan syndrome that had the novel IVS31-2A > G splice site mutation in fibrillin-1. This mutation affects the second base of the acceptor consensus splice site of intron 31, and probably leads to abnormal splicing events. The patient presented with respiratory distress and heart murmur in early neonatal life. Cardiac evaluation revealed pulmonic stenosis, atrioventricular regurgitation, and a dilated aortic root that were controlled by balloon dilatation of the pulmonic stenosis and medications for congestive heart failure. At age 3 months, he presented with severe respiratory distress caused by upper and lower airway obstruction. Imaging studies showed severe pulmonary emphysema, and a bronchoscopy demonstrated megatracheobronchomalacia, an unusual finding in this syndrome. Subsequently, the patient developed recurrent hyperinflation of the right and left lungs, with emphysematous changes and mediastinal shift. After discussing with his parents the grave prognosis for neonatal Marfan syndrome, he was discharged home with oxygen treatment and died at home at age 4.5 months. This case report demonstrates and discusses pulmonary involvement in neonatal Marfan syndrome and the difficult therapeutic challenges created by the severe cardiopulmonary abnormalities in this invariably fatal condition.

Giant intracranial aneurysm and fibromuscular dysplasia in an adolescent with alpha 1-antitrypsin deficiency

Recent studies have suggested that a deficiency of alpha 1-antitrypsin may be a genetic risk factor for the development of intracranial aneurysms and arterial fibromuscular dysplasia. The authors report a 16-year-old girl with a history of lung disease who suffered a cerebral hemorrhage due to the rupture of a giant intracranial aneurysm arising from the middle cerebral artery. This fusiform aneurysm was associated with fibromuscular dysplasia of the intimal type. She was found to have an unusual alpha 1-antitrypsin deficiency (PiMP phenotype). This case provides further evidence of an underlying arteriopathy in alpha 1-antitrypsin deficiency.