Diagnosing alpha-1 antitrypsin deficiency: does it prevent or improve the course of COPD?

Update on and future perspectives for the diagnosis of alpha-1 antitrypsin deficiency in Brazil

Alpha-1 antitrypsin deficiency (AATD) is a rare genetic disorder caused by a mutation in the SERPINA1 gene, which encodes the protease inhibitor alpha-1 antitrypsin (AAT). Severe AATD predisposes individuals to COPD and liver disease. Early diagnosis is essential for implementing preventive measures and limiting the disease burden. Although national and international guidelines for the diagnosis and management of AATD have been available for 20 years, more than 85% of cases go undiagnosed and therefore untreated. In Brazil, reasons for the underdiagnosis of AATD include a lack of awareness of the condition among physicians, a racially diverse population, serum AAT levels being assessed in a limited number of individuals, and lack of convenient diagnostic tools. The diagnosis of AATD is based on laboratory test results. The standard diagnostic approach involves the assessment of serum AAT levels, followed by phenotyping, genotyping, gene sequencing, or combinations of those, to detect the specific mutation. Over the past 10 years, new techniques have been developed, offering a rapid, minimally invasive, reliable alternative to traditional testing methods. One such test available in Brazil is the A1AT Genotyping Test, which simultaneously analyzes the 14 most prevalent AATD mutations, using DNA extracted from a buccal swab or dried blood spot. Such advances may contribute to overcoming the problem of underdiagnosis in Brazil and elsewhere, as well as being likely to increase the rate detection of AATD and therefore mitigate the harmful effects of delayed diagnosis.

Small airway evaluation in three subjects with alpha-1 antitrypsin deficiency without diagnosed lung disease

We describe three cases of female subjects (aged 16, 44 and 41 years) with no respiratory symptoms, who have alpha-1 antitripsyn mutation (PiSZ, PiZZ and PiZZ) and who performed traditional pulmonary function tests and the single breath nitrogen washout test. They still did not have chronic obstructive pulmonary disease (COPD) or any identifiable change in traditional pulmonary function tests but already have change in nitrogen washout tests. Alpha-1 antitrypsin deficiency is a genetic disorder associated with early-onset COPD. There is evidence that although patients who have well-preserved FEV₁ may already have signs of emphysema associated with symptoms. Therefore, the nitrogen washout test is considered to have more sensitive outcomes than other pulmonary function tests for early investigation of small airways disease and could allow the monitoring pulmonary function and evaluating of therapeutic decision.

The patient profile of individuals with Alpha-1 antitrypsine gene mutations at a referral center in Brazil

Objective:

The clinical, functional, radiological and genotypic descriptions of patients with an alpha-1 antitrypsin (A1AT) gene mutation in a referral center for COPD in Brazil.

Methods:

A cross-sectional study of patients with an A1AT gene mutation compatible with deficiency. We evaluated the A1AT dosage and genotypic, demographic, clinical, tomographic, and functional characteristics of these patients.

Results:

Among the 43 patients suspected of A1AT deficiency (A1ATD), the disease was confirmed by genotyping in 27 of them. The A1AT median dosage was 45 mg/dL, and 4 patients (15%) had a normal dosage. Median age was 54, 63% of the patients were male, and the respiratory symptoms started at the age of 40. The median FEV1 was 1.37L (43% predicted). Tomographic emphysema was found in 77.8% of the individuals. The emphysema was panlobular in 76% of them and 48% had lower lobe predominance. The frequency of bronchiectasis was 52% and the frequency of bronchial thickening was 81.5%. The most common genotype was Pi*ZZ in 40.7% of participants. The other genotypes found were: Pi*SZ (18.5%), PiM1Z (14.8%), Pi*M1S (7.4%), Pi*M2Z (3.7%), Pi*M1I (3.7%), Pi*ZMnichinan (3.7%), Pi*M3Plowell (3.7%), and Pi*SF (3.7%). We did not find any significant difference in age, smoking load, FEV1, or the presence of bronchiectasis between the groups with a normal and a reduced A1AT dosage, neither for 1 nor 2-allele mutation for A1ATD.

Conclusions:

Our patients presented a high frequency of emphysema, bronchiectasis and bronchial thickening, and early-beginning respiratory symptoms. The most frequent genotype was Pi*ZZ. Heterozygous genotypes and normal levels of A1AT also manifested significant lung disease.

Evaluation of alpha-1-antitrypsin levels in blood serum of patients with chronic obstructive pulmonary disease

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a disease that causes obstructed air flow from the lungs. The disease also has a dramatic role in increasing rate of mortality and morbidity in recent years. Air pollution, long-term exposure to particulate matter and irritating gases, especially cigarette smoke, genetic inheritance which has an impact on the initial forced expiratory volume one in second (FEV1), and alpha-1-antitrypsin (AAT) deficiency are among common COPD risk factors. The objective of this study is to evaluate parameters and serum AAT levels in COPD patients.

MATERIALS AND METHODS

Having taken the approval of local ethical committee, this cross-sectional study was performed with adult patients diagnosed with COPD, whose serum AAT levels were measured through nephelometric analysis in Kars Harakani State Hospital where secondary health care is served. The study evaluated ATT levels in patients' serum in relation to their age, gender, body mass (BMI), exposure to cigarette smoke, FEV1 percentage, hospitalization in pulmonology or intensive care unit through a year, mortality status, white blood cell (WBC), c-reactive protein (CRP) and blood gases.

RESULTS

The average age of the 243 patients included in the study was 68.41±11.52 and 160 (65.8%) of them were male. The age and BMI of the female patients were higher. Of the all patients only a single patient's serum AAT level was below the reference value. AAT levels were similar in both genders irrespective of their being exposed to cigarette smoke or being discharged or being exitus at their first admission to hospital, being exitus in the first year of disease diagnose, and being hospitalized in intensive care unit. AAT levels were reasonably correlated with WBC and CRP in a positive way (p<0.001 r=0.289 for WBC; p<0.001, r=0.295 for CRP). AAT levels were seen to significantly increase along with COPD stages which go up with FEV1 percentages (p<0.001). CRP was watched to have increased to Stage III COPD (severe COPD). However, it was watched to have decreased in Stage IV (very severe COPD) (p =0.179).

CONCLUSION

In the study, AAT serum levels of COPD patients were examined. The levels and their relations in various parameters of the patients were evaluated.