Study of familial alpha-1-proteinase inhibitor deficiency including a rare proteinase inhibitor phenotype (IZ). I. Alpha-1-phenotyping and clinical investigations

Proteinase inhibitor (PI) phenotyping and clinical investigations were performed on 20 persons in three generations of a family with alpha 1-antitrypsin deficiency. Two persons were homozygotes and 9 were heterozygotes for the Z allele; one is the first reported IZ phenotype; 11 were common M-types. Both homozygotes and 5 of the heterozygotes, including the IZ individual, had suffered from recurring or chronic respiratory diseases. However, only mild to moderate impairment in lung function tests was observed in some of these patients (DLCO steady state, 3 subjects; FEV1, 3 subjects; FEF25-75, 2 subject; elevation of RV, 2 subjects). The rare IZ type, a 35-year-old female, smoker, showed normal lung function except for an elevated RV. Our results indicate that PI deficiency is not necessarily associated with severe lung destruction if noxious inhalants are absent.     

Pulmonary function associated with the Mmalton deficient variant of alpha 1-antitrypsin

We have studied 78 members of a large family in which the Mmalton deficiency allele of alpha 1-antitrypsin (alpha 1AT) is present. Four patients of PI type MmaltonZ (alpha 1AT concentration, 16.4% of normal) had severe emphysema and marked depression in all flow and gas exchange parameters, significantly different from other members of the same family who were normal or had intermediate concentrations of alpha 1AT. Fourteen subjects with PI type MMmalton (alpha 1AT concentration, 63.3% of normal) were compared with 46 PI MM relatives (alpha 1AT, 103.8% of normal) and 14 relatives of PI type MZ (alpha 1AT concentration, 66.5% of normal). Spirometry, flow-volume loops, plethysmography, gas exchange at rest and exercise, and xenon 133 regional lung function were similar in those partially deficient when compared with the normal subjects. There was a trend for impairment of tests of lung function between smoking partially deficient (PI MZ, PI Mmalton) and normal (PI MM) relatives.     

The protease inhibitor PI*S allele and COPD: a meta-analysis.

In many countries, the protease inhibitor (SERPINA1) PI*S allele is more common than PI*Z, the allele responsible for most cases of chronic obstructive pulmonary disease (COPD) due to severe alpha 1-antitrypsin deficiency. However, the risk of COPD due to the PI*S allele is not clear. The current authors located studies that addressed the risk of COPD or measured lung function in individuals with the PI SZ, PI MS and PI SS genotypes. A separate meta-analysis for each genotype was performed. Aggregating data from six studies, the odds ratio (OR) for COPD in PI SZ compound heterozygotes compared with PI MM (normal) individuals was significantly increased at 3.26 (95% confidence intervals (CI): 1.24-8.57). In 17 cross-sectional and case-control studies, the OR for COPD in PI MS heterozygotes was 1.19 (95%CI: 1.02-1.38). However, PI MS genotype was not associated with COPD risk after correcting for smoking. Furthermore, mean forced expiratory volume in one second, a measure of airflow obstruction and a defining feature of COPD, did not differ between PI MS and PI MM individuals. There were not enough cases to summarise the risk of COPD in PI SS homozygotes. In conclusion, the results show that the PI SZ genotype is a significant risk factor for chronic obstructive pulmonary disease. The risk of chronic obstructive pulmonary disease due to the PI MS genotype is not substantially elevated.     

The prevalence of alpha(1)-antitrypsin deficiency in a representative population sample from Poland

AIM: Severe alpha(1)-antitrypsin (AAT) deficiency is one of the most common genetic disorders in Caucasians. The aim of the present study was to assess an unbiased frequencies of PI*S and PI*Z alleles using genotyping of a representative sample from the general population of Poland. METHODS: A random sample of age- and gender-stratified residents, aged 20 years or older, was drawn from the municipal directory of Kraków, Poland. The two most common deficiency alleles: PI*S and PI*Z were genotyped with qualitative real-time PCR using degenerative dual-labeled allele-specific fluorescent probes. RESULTS: In the total population of 859 adult subjects (mean age: 49.5 years; range: 20-90), 28 heterozygotes MS, 18 heterozygotes MZ and one homozygote S were diagnosed. The frequency of PI*S allele was 17.5 (95% CI: 11.6-23.9) per 1000; and that of PI*Z was 10.5 (95% CI: 5.8-15.7) per 1000. Therefore, the estimated prevalence of inherited severe AAT deficiency (homozygotes Z) in Poland is 1/9110 (95% CI: 1/4057-1/29,727). CONCLUSIONS: In the whole population of Poland comprising 38 millions, one may expect of about 4189 (95% CI: 1284-9406) subjects with severe AAT deficiency. These numbers are high enough to consider genetic testing being introduced into a common clinical practice.     

Diffuse hepatocellular dysplasia and carcinoma associated with the Mmalton variant of alpha 1-antitrypsin

The cirrhosis and hepatocellular carcinoma associated with alpha 1-antitrypsin deficiency has been exclusively reported with the PI Z allele. We present a 63-yr-old white man with emphysema, cirrhosis, and hepatocellular carcinoma. The latter occurred on a background of diffusely distributed hepatocellular dysplasia. Serum protein electrophoresis suggested a deficiency of alpha 1-antitrypsin quantitated at 13% of normal. PI phenotyping showed that he had only the rare PI Mmalton allele, previously associated only with severe lung disease. Family studies demonstrated the distribution of this rare allele. The liver at autopsy displayed well-differentiated hepatocellular carcinoma in addition to alpha 1-antitrypsin deposits in normal, dysplastic, and malignant cells.     

Alpha-1-antitrypsin genotyping with mouthwash specimens.

Alpha1-antitrypsin (alpha1-AT) deficiency is diagnosed as a two-stage procedure (concentration and phenotype). However the latter does not provide clues to the presence of null genes without family studies and obtaining blood from patients at a distance often proves difficult. The aim of the study was to assess the feasibility of genotyping alpha1-AT using buccal cells. Mouthwash specimens were sent by 84 patients (with a variety of phenotypes of alpha1-antitrypsin) through the post. Deoxyribonucleic acid (DNA) was isolated from buccal cells in each sample and subjected to polymerase chain reaction (PCR) using a genotyping kit to detect the S and Z alleles. Eighty-three of 84 samples received were suitable for amplification. The specific primers successfully identified the S and Z alleles in each case. However, five of the 35 samples obtained from patients thought to be Z allele homozygotes were found to be heterozygotes for another severe deficiency allele. These data confirm the feasibility of "at distance" testing for alpha1-antitrypsin deficiency alleles using buccal cells from mouthwash samples. The results raise the possibility that other deficiency alleles are more common than has previously been suspected.     

Study of alpha1-antitrypsin phenotypes frequencies in patients with primary antibody deficiency

Primary antibody deficiencies are the most frequent primary immunodeficiency disorders. Bronchiectasis as a feature of these disorders may be developed due to some factors such alpha-1- antitrypsin deficiency. In order to determine the prevalence of two common alpha-1-antitrypsin deficiency alleles (PI*Z and PI*S) in Iranian patients with antibody deficiency, this study was performed. The prevalence of PI*M, PI*S, and PI*Z allele combinations was determined in 40 patients with primary antibody deficiency (with and without bronchiectasis) and compared with 60 healthy control subjects. Phenotyping was performed by isoelectric focusing. The phenotype frequencies among patients were as follow: M in 92.5%, S in 2.5% and Z in 5%. There was not any significant difference in distribution of alleles or phenotypes between patients and control subjects. Moreover, no significant difference was found between patients with and without bronchiectasis. We did not find evidence to support an association between alpha-1-antitrypsin phenotypes and primary antibody deficiencies in a small, controlled study. Larger studies will be required to clarify the relationship between alpha-1-antitrypsin genotype and susceptibility to bronchiectasis in patients with antibody deficiency.     

The flaccid lung syndrome and alpha 1-protease inhibitor deficiency

We examined breathing mechanics and alpha 1PI deficiency in 1,850 unrelated male subjects with various lung complaints. The loss in lung elasticity appeared to be significantly more pronounced in ZZ individuals as compared to MM, MS and also MZ individuals. The MZ group did not differ significantly in this respect from MM individuals. This implies that the excess risk of developing a flaccid lung (C greater than 1 kPa-1) due to the partial alpha 1-antitrypsin deficiency is negligible. PI MZ and PI ZZ frequencies are significantly higher in the population with flaccid lung compared to control subjects. Furthermore, it was found that the increase in residual volume in smokers is independent of the PI type.     

Evaluation of the S-type of alpha-1-antitrypsin as an in vivo and in vitro inhibitor of neutrophil elastase

S-type alpha 1-antitrypsin (alpha 1AT) is a deficiency haplotype that differs from the common normal M1 (val213) alpha 1AT haplotype by a single amino acid (glu264 to val264). To evaluate the adequacy of the antineutrophil elastase protection associated with the S homozygous state, alpha 1AT plasma and lung epithelial lining fluid (ELF) levels and antineutrophil elastase function were analyzed in 9 PISS subjects. The plasma alpha 1AT levels of SS subjects were intermediate between that of M1M1 and ZZ subjects (p less than 0.001, all comparisons) and the plasma neutrophil elastase inhibitory capacity paralleled the differences in alpha 1AT concentration (p less than 0.001, all comparisons). The association rate constant for neutrophil elastase of the purified S protein was less than that of the normal molecule (S-type, 7.1 +/- 0.1 X 10(6) M-1 s-1; M1-type, 9.6 +/- 0.2 X 10(6) M-1 s-1; p less than 0.001), but much greater than that for the Z molecule (p less than 0.001). Exposure of the purified S protein to increasing oxidant burdens resulted in a dose-dependent reduction in the ability of the molecule to inhibit neutrophil elastase in a fashion parallel to that of the M1 and Z proteins. Quantification of ELF alpha 1AT levels and antineutrophil elastase capacity demonstrated that the SS ELF parameters were, as in plasma, intermediate between M1 homozygotes and Z homozygotes. Using the association rate constant together with the quantification of ELF alpha 1AT levels, the "in vivo lung inhibition time" was estimated, yielding an assessment of the relative antineutrophil elastase screen of the PISS lower respiratory tract.(ABSTRACT TRUNCATED AT 250 WORDS)     

Alpha1-antitrypsin and neutrophil elastase imbalance and lung cancer risk

OBJECTIVE: Imbalance between alpha(1)-antitrypsin and neutrophil elastase is an underlying cause of lung tissue damage that may create a favorable host environment for carcinogenesis. We conducted a case-control study to investigate whether genetic variations indicative of alpha(1)-antitrypsin deficiency (A1ATD) or an excess of neutrophil elastase modify lung cancer risk DESIGN: The case patients were 305 consecutively identified primary lung cancer patients, and the control subjects were 338 community residents. Protease inhibitor-1 (PI1), encoding alpha(1)-antitrypsin, was typed by an isoelectric focusing assay. Neutrophil elastase-2 (ELA2), encoding neutrophil elastase, was typed by two single-nucleotide polymorphism sites. Multivariable logistic regression models tested the independent and interactive effects of PI1, ELA2, tobacco smoke exposure, COPD, and family history of lung cancer RESULTS: Sex and ethnicity were comparable between case patients and control subjects, but case patients were more likely to be smokers, and to have a history of COPD, environmental tobacco smoke exposure, and a positive family history of lung cancer. Haplotype analysis indicated an overall strong association between the two ELA2 markers and lung cancer risk. Our best-fitting model showed significant and independent effects of the PI1-deficient allele (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.4 to 3.0) and the ELA2 T-G haplotype (OR, 4.1; 95% CI, 1.9 to 8.9) on lung cancer risk, and an increased risk (OR, 2.6; 95% CI, 2.4 to 2.8) for individuals carrying both a PI1-deficient allele and a G-G haplotype CONCLUSIONS: Genotypes indicative of A1ATD and/or an excess of neutrophil elastase are significantly associated with lung cancer risk. Our findings may provide opportunities to better understand the mechanisms of lung cancer development and risk reduction.     

Pulmonary function in heterozygotes for alpha,-antitrypsin deficiency: a case-control study.

In this paper we present the initial cross-sectional data from a prospective study of lung aging in heterozygotes for alpha 1-antitrypsin deficiency. Using a case-control design, our cases included 37 heterozygotes for alpha 1-antitrypsin deficiency, protease inhibitor phenotypes MZ and MS, selected because they were parents of children with homozygous alpha 1-antitrypsin deficiency identified in a statewide newborn screening program between 1971 and 1974. All of the heterozygotes were less than 40 yr of age. Our control subjects were selected from a random sample of a working population participating in a longitudinal study of lung aging, using a 2:1 match of control subjects to cases, matching age, sex, ethnic origin, and smoking. Using a respiratory symptom questionnaire, spirometry, and the single-breath N2 test, we found no significant difference between heterozygotes and control subjects in terms of respiratory symptoms or pulmonary function data. We conclude that to 40 yr of age, the heterozygous phenotype (Pi MZ and MS) is not a risk factor for impairment of pulmonary function.     

The direct medical costs of alpha(1)-antitrypsin deficiency

BACKGROUND: For individuals with emphysema because of severe alpha(1)-antitrypsin deficiency, specific therapy called IV augmentation therapy has been available since 1989. Such therapy consists of IV infusion of pooled human plasma alpha(1)-antiprotease. METHODS: To assess the direct medical costs of having alpha(1)-antitrypsin deficiency, the current study surveyed members of the Alpha One Foundation Registry for Individuals With alpha(1)-Antitrypsin Deficiency regarding their annual expenditures for treatment of this disease. Data regarding demographic features, alpha(1)-antitrypsin status, and health-resource utilization were collected from a self-administered questionnaire. Respondents were asked to provide total health-care expenditures, but costs by specific items of care (eg, drugs, physician visits, etc) were not available. RESULTS: Mean annual cost estimates were higher for PI*ZZ-phenotype individuals ($30,948, n = 292) than for non-PI*ZZ-phenotype individuals ($20,673, n = 53; p = 0.049). Among PI*ZZ-phenotype individuals, self-reported costs of health-care services were further analyzed for those 288 individuals whose alpha(1)-antiprotease use status was reported. For the 185 current alpha(1)-antiprotease users, the mean annual cost was $40,123 (median, $36,000). CONCLUSIONS: Annual health-care expenditures by individuals with alpha(1)-antitrypsin deficiency are very high, whether or not they are currently receiving augmentation therapy. Augmentation therapy adds substantial costs, especially for heavier individuals who are receiving weekly infusions.     

Alpha-1-antitrypsin deficiency. High prevalence in the St. Louis area determined by direct population screening

Considerable attention has been focused upon alpha-1-antitrypsin deficiency because of the insights into the pathogenesis of human pulmonary emphysema that may derive from study of deficient subjects, and because of evolving therapeutic strategies that may slow the progression of lung disease in affected persons. We have applied an automated immunoassay for alpha-1-antitrypsin to plasma samples from 20,000 blood donors. Seven PI Z antitrypsin-deficient persons were identified and confirmed; this is more than twice the number predicted from previous estimates of the Z allele frequency in the St. Louis area. Five of the subjects were further evaluated. We anticipate that this assay, if utilized to screen large populations, could identify many alpha-1-antitrypsin-deficient persons for study of the natural history of lung and liver disease associated with the deficiency. These subjects would be potential candidates for early intervention strategies to prevent the development of lung disease. The surprisingly high prevalence of deficient persons indicates that direct screening is the best method for prevalence estimation of genetic disorders.     

Alpha1-antitrypsin deficiency: genetic, clinical and functional correlations in a three generation family.

alpha1-antitrypsin (alpha1-AT) deficiency is a hereditary condition transmitted as an autosomal codominant trait. Fully deficient homozygotes develop chronic obstructive pulmonary disease at an early age. It remains controversial whether heterozygotes develop some degree of airway disease at an early age which results in severe obstructive disease later in life. We studied 12 alpha1-AT-deficient members of a family spanning three generations by extensive pulmonary function tests, clinical history and genetic determinations. 3 of the subjects were homozygotes and showed important clinical and lung function abnormalities by the age of 30. Two out of 9 heterozygotes, a female and a male, had decreased dynamic compliance, elevated closing volume and low PaO2. 3 showed clinical and physiological abnormalities (elevation in functional residual capacity and residual volume, low FEV1/FVC and elevated closing volume); however, these alterations could be attributed to their smoking habits or concomitant medical condition. The remaining 4 subjects were normal. None of the heterozygotes showed alterations in the static elastic recoil of the lung or static compliance.     

Evaluation of danazol therapy for patients with PiZZ alpha-1-antitrypsin deficiency

An inherited deficiency of alpha 1-antitrypsin with blood concentrations less than 80 mg/dl is associated with the accelerated development of emphysema. Current concepts of the pathogenesis of emphysema suggest that an imbalance between neutrophil elastase and alpha 1-antitrypsin in the lung allows neutrophil elastase to work unimpeded to destroy the alveolar structures. Because the common form of the inherited deficiency (homozygous Z) results from impaired hepatic release of alpha 1-antitrypsin, one therapeutic approach to increase plasma and hence lung alpha 1-antitrypsin concentrations is to enhance hepatic release or production of alpha 1-antitrypsin. In a preliminary trial with 6 alpha 1-antitrypsin-deficient subjects, we have previously shown that in 1 month, the impeded androgen danazol can augment serum alpha 1-antitrypsin concentrations by 37%. To evaluate the use of impeded androgens in alpha 1-antitrypsin deficiency on a broader scale, we have treated: 43 homozygous Z patients with danazol 200 mg given orally 3 times a day for 30 days; 6 homozygous Z patients with a similar danazol dose but given for 6 to 18 months; and 7 homozygous Z patients with stanazolol, another synthetic androgen, 2 mg given orally 3 times a day for 30 days. Of the 43 patients treated with danazol for 1 month, 23 (53%) responded with a serum alpha 1-antitrypsin concentration greater than or equal to 20% higher than baseline, an average increase of 52% over the pretreatment concentration.(ABSTRACT TRUNCATED AT 250 WORDS)     

alpha1-Antitrypsin augmentation therapy for PI*MZ heterozygotes: a cautionary note

The use of IV augmentation therapy with plasma-derived alpha1-antitrypsin (AAT) has become the standard of care for the treatment of pulmonary disease associated with the severe genetic deficiency of AAT. The Medical and Scientific Advisory Committee of the Alpha-1 Foundation has become aware that physicians are prescribing this expensive blood product for the treatment of individuals with a single abnormal AAT gene, primarily the PI*MZ genotype. We are aware of no evidence that such therapy is effective in this patient population. The most important therapeutic interventions in such patients remain smoking cessation and elimination of other risk factors for lung disease. This commentary discusses the treatment of AAT deficiency and the concerns regarding treatment of PI*MZ individuals. We conclude that clinicians should avoid prescribing augmentation therapy for this heterozygote population.     

Secondary outputs of alpha1-antitrypsin deficiency targeted detection programme

Targeted detection programmes are recommended to identify subjects affected by severe alpha1-antitrypsin deficiency (AATD). Guidelines are available to address physicians towards subjects at high risk for AATD. We wanted to investigate the clinical characteristics of subjects enrolled in the programme, who result as not being affected by severe AATD; this information is not available in the present literature. We elaborated data contained in the questionnaires accompanying the samples of 2127 Italian subjects submitted for AATD detection in a period spanning 11 years (1996-2006). A total of 588 subjects were eligible to enter this study: PI*MM subjects and subjects with intermediate AATD, referred for lung disease, were characterised by a relatively young mean age, and a high proportion (31.2% and 28.6%, respectively) were never smokers. Fifty percent or more had symptoms of chronic bronchitis, but without obstruction. Only a minority belonged to most severe GOLD stages. The mean levels of AAT varied as a function of the presence or absence of airflow obstruction in intermediate AATD subjects, but not in PI*MM. Individuals enrolled in AATD detection programmes represent an interesting cohort both for public health and research purposes.     

Genetics of chronic obstructive pulmonary disease

Variability in the susceptibility to develop chronic obstructive pulmonary disease (COPD) is related to both genetic and environmental factors. COPD is likely a genetically complex disease, but severe alpha 1-antitrypsin (AAT) deficiency [e.g., protease inhibitor (PI) Z] remains the only proven genetic risk factor for COPD. Even among PI Z individuals, substantial variability in lung function is observed, suggesting that genetic modifiers may influence the expression of lung disease in severe AAT deficiency. The variable development of COPD in smokers without alpha 1-antitrypsin deficiency and the familial aggregation of lung function measurements also suggest the presence of genetic influences on lung function growth and decline leading to COPD. Many candidate gene loci have been investigated as potential COPD genetic determinants by case-control genetic association studies. However, inconsistent results of these association studies have been frequent. Genetic heterogeneity and population stratification are two potential reasons for the conflicting findings between association studies. Linkage analysis studies have recently been published that may identify regions of the genome that contain COPD susceptibility genes. Future investigations of genetic influences in COPD should consider the use of family-based designs for association studies and the study of positional candidate genes within regions of linkage.     

Descripción de la deficiencia de alfa-1-antitripsina asociada al alelo PI*Q0ourém en la isla de La Palma (España) y de un método de genotipado para su detección

By analysis of a case of discrepancy between serum alpha-1-antitrypsin (AAT) level and genotype for the most common defective alleles associated with AAT deficiency (PI*S and PI*Z), a patient carrying the allele PI*Q0_ourém has been identified for the first time outside of Portugal. This null allele has been implicated in cases of severe pulmonary emphysema. After developing a clinical assay for detection of c.1130insT mutation, based on fluorescent probes (HybProbe^®), another 4 carriers of PI*Q0_ourém allele were identified among 43 patients with abnormally low serum AAT levels based on their genotypes for PI*S and PI*Z alleles. Since 4 out 5 cases are from the same locality (La Palma Island, Spain), it is advisable to conduct genetic analyses of affected families and, possibly, a focused population screening.