Alpha 1-antitrypsin genes in patients with alpha 1AT deficiency in Japan: mutational analysis and allelic background]

Deficiency of alpha 1-antitrypsin (alpha 1AT), a plasma serine protease inhibitor, increases the risk of precocious pulmonary emphysema. Patients with alpha 1AT deficiency in Japan are extremely rare and no Z type alpha 1AT deficiency, which is one of the most frequent genetic disorders among Caucasians, are reported in Japan at the level of gene analysis. It is not yet clear why Z type alpha 1AT is rare among Japanese. When Ala213(GCG)-Val213(GTG) mutation in the alpha 1AT gene was examined by restriction endonuclease BstPI, all of 156 Japanese samples were Val213(GTG) in contrast to the finding that 30% of U.S. Caucasians are Ala213(GCG), indicating that alpha 1AT genes among Japanese were diverted from M1(Val213) variant and are different from M1(Ala213) variant, from which Z variant was likely diverted. This may explain why Z type alpha 1AT deficiency is not found among Japanese. A new alpha 1AT deficient variant, Siiyama (Ser53(TCC)-Phe53(TTC)), was found in a 39-year-old male with pulmonary emphysema (Seyama K, et al, J Biol Chem, 266, 12627, 1991). Interestingly, 6 out of 10 families with alpha 1AT deficiency in Japan shared the identical substitution as Siiyama. This indicates that although Caucasian type Z alpha 1AT deficiency is not found, Siiyama variant may be relatively common in Japan and even in other oriental countries because of the historical migration of people.     

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.     

Alpha1-antitrypsin genotypes in patients with chronic pancreatitis

BACKGROUND: An association between alpha1-antitrypsin deficiency and chronic pancreatitis (CP) has been reported in several case reports and two systematic studies. However, conflicting results have been shown in other studies of patients with CP. All previous studies were performed by phenotyping or by measurement of serum concentrations of alpha1-antitrypsin. The aim of this study was to investigate the relationship between alpha1-antitrypsin deficiency and CP by genetic analysis. METHODS: Ninety-six unrelated children and adolescents with idiopathic or hereditary CP and 185 healthy controls were enrolled. DNA was extracted from peripheral blood leukocytes and the exons 5 and 7 of the alpha1-antitrypsin gene were amplified by polymerase chain reaction using mutagenic forward primers introducing a Taq I restriction site. Genotyping of the S allele and the Z allele was performed by restriction fragment length polymorphism analysis using Taq I. RESULTS: Seven out of 96 patients (7.3%) with CP were heterozygous for an alpha1-antitrypsin deficiency allele (4 for the S allele and 3 for the Z allele). No patient was homozygous or compound heterozygous for these alleles. Twenty out of 185 control individuals (10.8%) were heterozygous for the S or Z allele (PiS: 12 controls; PiZ: 8 controls). No significant differences were found between the allele frequency in patients and the control individuals (P > 0.1). CONCLUSIONS: Alpha1-antitrypsin deficiency is not related to the pathogenesis of idiopathic or hereditary CP.     

The Ser 460 to Pro substitution of the protein S alpha (PROS1) gene is a frequent mutation associated with free protein S (type IIa) deficiency

A Ser 460 to Pro mutation of protein S (PS), involving a T to C transition in exon XIII of the protein S alpha (PROS1) gene and known as the Heerlen polymorphism, was found in 16 of 85 symptomatic patients with PS deficiency (18.8%) and only 1 of 113 healthy subjects (0.8%). Another frequent polymorphism was described in exon XV of the PROS1 gene, in the codon for Pro 626 (CCA/CCG). We found that Heerlen polymorphism was associated with allele CCA and not with allele CCG, suggesting a probable transmission by a common ancestor. Most subjects bearing the Ser 460 to Pro mutation were deficient in free PS, but had normal total PS levels. Normal levels of the C4b-binding protein (C4b- BP) isoform containing a beta chain (C4b-BP beta +) ruled out increased C4b-BP beta + as a cause of the free-PS deficiency. The binding curves of the mutated (Heerlen) PS on C4b-BP immobilized on microplates were biphasic, suggesting that one molecule of C4b-BP can bind two molecules of Heerlen PS. Because normal PS binds to C4b-BP with 1:1 stoichiometry, this may explain the free-PS deficiency observed in patients carrying the Ser 460 to Pro mutation.     

Use of a highly purified alpha 1-antitrypsin standard to establish ranges for the common normal and deficient alpha 1-antitrypsin phenotypes

Diagnosis of the hereditary disorder alpha 1-antitrypsin (alpha 1AT) deficiency is critically dependent on quantification of serum levels of alpha 1AT, a 52-kDa antiprotease that serves to protect the lung from destruction by neutrophil elastase. Although the measurement of serum alpha 1AT levels is not difficult, there is no international standard for alpha 1AT, and investigators in the field recognize that widely used commercially available standards vary by as much as 50 percent. To establish accurate ranges for the common normal and deficient alpha 1AT phenotypes, the present study uses a purified alpha 1AT standard to quantify the alpha 1AT serum levels of 443 individuals with common normal and deficient alpha 1AT phenotypes, including MM, ZZ, SS, MZ, MS, and SZ. Based on the observed values, a statistical model was developed to generate predicted frequency distributions of alpha 1AT serum levels for each of these phenotypes. Based on these studies, the ranges (5th to 95th percentile) for alpha 1AT serum levels of the common phenotypes are: MM, 20 to 53 mumol/L; SS, 20 to 48 mumol/L; ZZ, 3.4 to 7.0 mumol/L; MZ, 15 to 42 mumol/L; MS, 18 to 52 mumol/L; and SZ, 10 to 23 mumol/L. This alpha 1AT standard and these ranges are being used for the National alpha 1-Antitrypsin Deficiency Registry organized under the auspices of the National Heart, Lung, and Blood Institute.     

Alpha1-antitrypsin deficiency may be a risk factor for duodenal ulcer in patients with Helicobacter pylori infection

BACKGROUND: Most individuals with Helicobacter pylori infection in Western countries have no evidence of peptic ulcer disease (PUD). We therefore assessed the PiZ deficiency variant of the major plasma protease inhibitor alpha1-antitrypsin (alpha1AT) as a risk factor for PUD in H. pylori-infected individuals. METHODS: The cohort comprised 100 patients with endoscopically or surgically proven PUD (30 patients with duodenal ulcer (DU) and 70 patients with gastric ulcer (GU)) and 162 age- and sex-matched controls with PUD-negative endoscopic findings and no history of PUD. Plasma samples were screened for alpha1AT deficiency (PiZ) with an enzyme-linked immunosorbent assay (ELISA) and phenotyped by isoelectric focusing. H. pylori infection was evaluated with an IgG ELISA technique. RESULTS: Among the 262 patients 17 (6.5%) were positive for the PiZ alpha1AT deficiency, a frequency of the same magnitude as in the Swedish general population (4.7%). Of the PiZ carriers 76% (13 of 17) had H. pylori antibodies compared with 61% (151 of 245) of the non-PiZ carriers (NS). The prevalence of DU tended to be higher in H. pylori-positive PiZ carriers than in non-PiZ carriers (15.4%, 4 of 26 versus 0 of 4). Furthermore, among patients with DU a high PiZ allele frequency (13.3%, 4 of 30) was found compared with the general population (4.7%) (odds ratio (OR), 3.2; 95% confidence interval (CI), 1.09-8.94; P = 0.02). All DU patients carrying the PiZ allele were positive for H. pylori. In addition, four of five PiZ carriers with H. pylori infection and PUD had DU. CONCLUSIONS: The PiZ allele may be a contributing factor in the development of DU in H. pylori-positive individuals.     

Rapid screening for alpha1-antitrypsin deficiency in patients with chronic obstructive pulmonary disease using dried blood specimens

We describe two reliable methods for high-throughput screening of proteinase inhibitor (PI) S and PI Z alpha(1)-antitrypsin (alpha(1)-AT) deficiency alleles from dried blood spot (DBS) specimens using the LightCycler fluorimetric analyzer. The method was used to study 72 patients with chronic obstructive pulmonary disease. Results were confirmed with DNA sequencing. The alpha(1)-AT concentration in DBS was determined with immune nephelometry. Sixteen patients (22%) showed no PI Z or PI S mutations. Five patients (7%) had a heterozygous genotype consisting of a PI S allele and a normal allele for the Z and S positions (non-S non-Z). Twenty-five patients (35%) had a heterozygous genotype consisting of a PI Z and a non-S non-Z allele. Two (3%) had the PI SS genotype, 2 (3%) the PI SZ, and 20 (28%) the PI ZZ. All patients with two normal alpha(1)-AT alleles and 10 heterozygous carriers of one normal and one deficient allele had alpha(1)-AT levels that fell within the alpha(1)-AT DBS normal range (1.8-3.1 mg/dl). Two patients with the rare PI MM(malton)- and PI MM(heerlen)-deficient variants showed deficient alpha(1)-AT levels; PI S and PI Z were not detected. Processing 32 samples requires only 40 minutes. This single-step, cost-effective technology is optimal for working with small amounts of DNA, as are present in DBS. The method is suitable for large-scale screening, in cases where PI type is important.     

Results of a case-detection programme for alpha1-antitrypsin deficiency in COPD patients.

Alpha1-antitrypsin (alpha1-AT) deficiency is an underdiagnosed condition in patients with chronic obstructive pulmonary disease (COPD). The present authors have conducted a nationwide case detection programme of alpha1-AT deficiency in unselected patients with COPD using dried blood spots. The first phase analysed samples from 971 patients by determining alpha1-AT concentrations and identifying the deficient Z allele by genotyping using rapid real-time PCR. The second phase analysed 1,166 samples with alpha1-AT concentrations and identified both the S and the Z allele, but only in samples with low alpha1-AT concentrations. A total of eight (0.37%) individuals with the severe deficiency PiZZ were detected. In addition, three patients were identified with the PiSZ genotype in the second phase (0.3%). The global cost of the programme was 41,512, which represents 19.42 per sample and 5,189 per PiZZ detected. A sensitivity analysis demonstrated that performing Z genotype to all samples would have resulted in increased costs of 28 per sample and 7,479.5 per PiZZ case identified. In conclusion, a case detection programme of alpha1-antitrypsin deficiency in patients with chronic obstructive pulmonary disease using dried blood spots is feasible and at a reasonable cost per case detected. Diagnostic yield and costs depend largely on inclusion criteria and the protocol for processing of samples.     

Prevalence of genetic polymorphisms in the promoter region of the alpha-1 antitrypsin (<Emphasis Type="Italic">SERPINA1</Emphasis>) gene in chronic liver disease: a case control study

Background  

Alpha-1 antitrypsin (A1AT) deficiency, caused by the Z allele (p.E342K) and S allele (p.E264V) in the SERPINA1 gene, can induce liver and pulmonary disease. Different mechanisms appear to be responsible for the pathogenesis of these divergent disease expressions. The c.-1973T >C polymorphism located in the SERPINA1 promoter region is found more frequent in A1AT deficiency patients with liver disease compared to patients with pulmonary disease, but data are lacking regarding contribution to the development of liver diseases caused by other aetiologies.     

Alpha1-antitrypsin deficiency: biological answers to clinical questions

Alpha1-antitrypsin (alpha1AT) deficiency is a common lethal hereditary disorder of white persons of European descent. The condition is characterized by reduced serum levels of alpha1AT, a 52-kDa glycoprotein synthesized chiefly in the liver and, to a lesser extent, by macrophages and neutrophils. Alpha1AT acts as an antiprotease and is the physiological inhibitor of neutrophil serine proteases such as neutrophil elastase cathepsin G and proteinase 3. The clinical manifestations of alpha1AT deficiency occur chiefly in the lung, with a high risk of emphysema occurring by the third or fourth decade of life. Cigarette smoking accelerates the development of emphysema in persons with alpha1AT deficiency. There is also an increased risk of liver disease in alpha1AT deficiency, which occurs mostly in childhood. In this review, we will define further the diagnosis of alpha1AT deficiency and its clinical manifestations and describe the therapeutic strategies that are currently being developed to treat the hepatic and pulmonary disease associated with this condition.     

Alpha-antitrypsin genotypes in Korean patients with chronic obstructive pulmonary disease

OBJECTIVE: Alpha1-antitrypsin (AAT) deficiency is a recognized susceptible factor for chronic obstructive pulmonary disease (COPD) in Western countries, but its importance in Korea is unclear. To date, no definitive case of alpha1-antitrypsin deficiency has been reported in Korea. This study aimed to clarify whether alpha1-antitrypsin deficiency exists and to determine the distribution of alpha1-antitrypsin alleles in the Korean population. METHODOLOGY: The serum concentrations of alpha1-antitrypsin were determined and polymorphisms of the alpha1-antitrypsin gene in 114 COPD patients and in 196 healthy controls were examined. Phenotyping by isoelectric focusing and the genotyping of alpha1-antitrypsin gene by polymerase chain reaction and restriction fragment length polymorphism were performed. RESULTS: No alpha1-antitrypsin level abnormality was found in the patients. M1(Val)/M1(Val) was found to be the most frequent genotype in both groups (69.2% and 66.8%, respectively), and M1(Val) the most frequent allele. The distributions of alpha1-antitrypsin alleles were similar in the patient and control groups, and no S or Z allele was found. CONCLUSION: Alpha1-antitrypsin deficiency is unlikely to be an important cause of chronic obstructive pulmonary disease in the Korean population.     

Evaluation of tamoxifen as a therapy to augment alpha-1-antitrypsin concentrations in Z homozygous alpha-1-antitrypsin-deficient subjects

Tamoxifen, an agent that binds to intracytoplasmic estrogen receptors, was evaluated as a possible means of increasing alpha-1-antitrypsin (alpha 1AT) synthesis and/or secretion and thus alpha 1AT serum levels in subjects with the homozygous form of alpha 1AT deficiency. Administration of tamoxifen (10 mg twice daily) to 30 Z homozygotes for a 30-day period was not associated with adverse reactions. However, although serum alpha 1AT levels increased significantly (p less than 0.03), the increase was minor (average pretreatment levels, 32 +/- 1 mg/dl; levels at 30 days of therapy, 35 +/- 1 mg/dl) and far below the "threshold" level of 80 mg/dl considered "protective" against an increased risk for emphysema. Thus, while the concept that increasing alpha 1AT synthesis and/or secretion is a rational goal for treating the Z homozygous form of alpha 1AT deficiency, tamoxifen will not be useful in this regard.     

Alpha 1-antitrypsin deficiency (Siiyama) with pulmonary emphysema]

A 44-year-old man was admitted to the hospital with dyspnea on exertion. Chest radiographs and pulmonary function tests showed evidence of pulmonary emphysema. Serum alpha 1-antitrypsin (alpha 1-AT) could not be detected by nephelometry, immuno-electrophoresis, or iso-electric focusing. However, allele-specific PCR revealed a genotype homozygotic for an alpha 1-AT deficient variant of the Siiyama allele. An elder sister of the proband was also a homozygous carrier of the Siiyama allele. The amino acid sequence for normal alpha 1-AT variants had been substituted by Arg101-Val213-Glu376 in the proband, demonstrating that the alpha 1-antitrypsin-deficient Siiyama variant in this pedigree was derived from M 1 (Val213).     

Alpha-1 antitrypsin deficiency: A conformational disease associated with lung and liver manifestations

Summary Alpha-1 antitrypsin (A1AT) is a serine anti-protease produced chiefly by the liver. A1AT deficiency is a genetic disorder characterized by serum levels of less than 11 μmol/L and is associated with liver and lung manifestations. The liver disease, which occurs in up to 15% of A1AT-deficient individuals, is a result of toxic gain-of-function mutations in the A1AT gene, which cause the A1AT protein to fold aberrantly and accumulate in the endoplasmic reticulum of hepatocytes. The lung disease is associated with loss-of-function, specifically decreased anti-protease protection on the airway epithelial surface. The so-called ‘Z’ mutation in A1AT deficiency encodes a glutamic acid-to-lysine substitution at position 342 in A1AT and is the most common A1AT allele associated with disease. Here we review the current understanding of the molecular pathogenesis of A1AT deficiency and the best clinical management protocols. Competing interests: None declared References to electronic databases: Alpha 1-antitrypsin deficiency: +107400. C.M. Greene and S.D.W. Miller contributed equally to the work.     

HLA-DRB1和肿瘤坏死因子α基因多态性与肝硬化的遗传易感性

目的探讨HLA-DRB1和肿瘤坏死因子(TNF)α基因多态性与肝硬化遗传易感性之间的关系.方法应用聚合酶链反应-序列特异性引物法、限制性片段长度多态性等技术检测106例乙型肝炎后肝硬化患者和108例健康对照者的HLA-DRB1和TNFα基因多态性.结果肝硬化组HLA-DRB1*120X等位基因频率比对照组显著升高(35.9%比11.1%,P＜0.001),TNFα中TNF2/1基因型频率比对照组明显升高(19.8%比10.2%, P＜0.05),DRB1*150X等位基因频率明显低于对照组 (13.2%比30.6% ,P＜0.05),分层分析表明,DRB1*120X等位基因与肝硬化的关联大于TNF2等位基因.结论 HLA-DRB1*120X和TNF2等位基因与乙型肝炎后肝硬化的遗传易感性相关,携带这2个等位基因的个体发生肝硬化的危险性增加.HLA-DRB1*120X等位基因可能是肝硬化的易感基因,HLA-DRB1*150X等位基因为抗性基因.     

Increased PiZ gene frequency for alpha 1 antitrypsin in patients with genetic haemochromatosis.

The putative relationship between genetic haemochromatosis and PiZ alpha 1 antitrypsin deficiency was studied using a monoclonal antibody against the PiZ variant in 67 consecutive patients with genetic haemochromatosis seen at Karolinska Hospital and Huddinge University Hospital, Stockholm over a 10 year period. Three (4.5%) of the patients with haemochromatosis were found to be PiZ homozygotes (odds ratio = 82, confidence interval = 26, 256; p < 0.0001). The prevalence of the heterozygous (PiZ) phenotype was similar to that in the general population (p = 0.937). During the ascertainment period, liver biopsy was performed in 65 (97%) of the patients; 66% (2 of 3) of the PiZ homozygotes were found to have cirrhosis compared with 10% (6/59) of the non-carriers of the PiZ variant (p = 0.039). None of the homozygous or heterozygous alpha 1 antitrypsin deficient patients had developed hepatocellular carcinoma compared with 3.4% (2 of 59) of the non-PiZ gene carriers (p = 1.0). Two of those with the homozygous phenotype had developed severe emphysema. HLA typing was performed in 18 patients, 16 (89%) of whom manifested antigens known to be linked to haemochromatosis. There were no significant differences between the PiZ gene carriers and non-carriers in mean age at onset of disease, sex distribution, or HLA type. Two of the PiZ heterozygotes had plasma alpha 1 antitrypsin concentrations below the normal range, though the group mean was lower than that of the non-PiZ carriers (p = 0.0003). The data suggest that the presence of the PiZ allele for alpha1 antitrypsin deficiency, in a double dose, is associated with genetic haemochromatosis and may contribute to the earlier onset of cirrhosis in these patients, though it does not increase the risk of hepatocellular carcinoma.