The dried blood spot (DBS) specimens have been successfully employed for the large-scale diagnostics of α1-antitrypsin (AAT) deficiency as an easy to collect and transport alternative to plasma/serum. In the present study we propose a fast, efficient, and cost effective protocol of DNA extraction from dried blood spot (DBS) samples that provides sufficient quantity and quality of DNA and effectively eliminates any natural PCR inhibitors, allowing for successful AAT genotyping by real-time PCR and direct sequencing. DNA extracted from 84 DBS samples from chronic obstructive pulmonary disease patients was genotyped for AAT deficiency variants by real-time PCR. The results of DBS AAT genotyping were validated by serum IEF phenotyping and AAT concentration measurement. The proposed protocol allowed successful DNA extraction from all analyzed DBS samples. Both quantity and quality of DNA were sufficient for further real-time PCR and, if necessary, for genetic sequence analysis. A 100% concordance between AAT DBS genotypes and serum phenotypes in positive detection of two major deficiency S- and Z- alleles was achieved. Both assays, DBS AAT genotyping by real-time PCR and serum AAT phenotyping by IEF, positively identified PI*S and PI*Z allele in 8 out of the 84 (9.5%) and 16 out of 84 (19.0%) patients, respectively. In conclusion, the proposed protocol noticeably reduces the costs and the hand-on-time of DBS samples preparation providing genomic DNA of sufficient quantity and quality for further real-time PCR or genetic sequence analysis. Consequently, it is ideally suited for large-scale AAT deficiency screening programs and should be method of choice.
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[Show abstract][Hide abstract] ABSTRACT: INTRODUCTION One percent of all liver transplantations is performed in subjects with hereditary homozygous alpha 1-antitrypsin (AAT) deficiency resulting in liver failure. OBJECTIVES To evaluate the role of heterozygous AAT deficiency in the development of liver failure requesting liver transplantation. PATIENTS AND METHODS We performed a prospective investigation in 304 (57% males) consecutive patients evaluated for orthotopic liver transplantation between 2009-2011 in a referral center at a University Hospital. AAT phenotyping, and etiology of liver disease, liver function, cardiopulmonary function tests were assessed in all subjects. RESULTS Viral hepatitis and alcohol were the most common causes of liver cirrhosis in the study group. These entities were responsible for liver cirrhosis in 21% and 12% of patients, respectively. Two hundred and eighty four patients presented with normal protease inhibitor (Pi)MM phenotype. In eleven subjects (4%), AAT phenotyping revealed PiMZ. This number was significantly higher than in the general Polish population (2%). PiMS phenotype was found in 6 (2%) patients, and this was not different similarly to PiS prevalence in the Polish population. Three heterozygous patients were identified with MP, IM, and MX phenotype. CONCLUSIONS The carriers of PiMZ phenotype bear an increased risk of developing severe liver failure independently of other risk factors being, most frequently, viral hepatitis and alcoholic cirrhosis.
Full-text · Article · Dec 2012 · Polskie archiwum medycyny wewnȩtrznej
[Show abstract][Hide abstract] ABSTRACT: α(1)-Antitrypsin (AAT) deficiency leads to deterioration of the lungs that can be prevented with diagnosis and treatment. Isoelectric focusing (IEF) electrophoresis is the current biochemical gold standard for detecting AAT deficiency variants but involves complex interpretation. Variant AAT samples were collected over a 2-year period. Stability of AAT for phenotype determination was assessed in whole blood, dried blood spots, and dried serum spots. A compendium displaying 13 common and 5 rare AAT phenotypes was created, and a detailed methodology describing how to recognize AAT banding patterns and interpret a rare phenotype accompanied these visual data. AAT was stable for IEF phenotype analysis for at least 1 week in whole blood and for 24 hours on dried serum spots. In conclusion, a reference compendium of known AAT phenotypes was established that can serve as a resource for interpreting AAT phenotypes.
Full-text · Article · Feb 2013 · American Journal of Clinical Pathology
[Show abstract][Hide abstract] ABSTRACT: Inherited alpha-1 antitrypsin (AAT) deficiency is one of the three most common genetic disorders in Caucasians. It considerably increases the risk of progressive obstructive lung diseases, mostly chronic obstructive pulmonary disease. It has also been suggested that AAT deficiency might be instrumental vasculitis associated with the anti-neutrophil cytoplasm antibodies (cANCA) and subsequent lung tissue injury.
We present the results from a pilot study involving 51 patients with granulomatosis with polyangiitis, formerly known as Wegener's granulomatosis (GPA), 43 of whom were cANCA positive. The control group consisted of 658 individuals. AAT blood concentration assessment by nephelometry, phenotyping by isoelectrofocusing and real-time PCR genotyping were performed.
Deficiency alleles PI*Z and PI*S were detected in 3 (5.88%) and in 2 patients (3.92%) with GPA, respectively. All of them were cANCA positive. In the controls, PI*Z was observed in 2.8% while PI*S in 1.5% of cases. Accordingly, the increased incidence of main deficiency alleles was demonstrated in GPA, and particularly in cANCA+GPA patients, when compared to the controls. The estimated frequency for PI*Z in GPA, cANCA+GPA patients and controls was, respectively, 29.4/1000, 34.9/1000 and 13.7/1000, whereas for PI*S it was 19.2/1000, 23.2/10,00 and 7.6/1000. However, the observed differences did not reach statistical significance due to the considerable size disproportion between groups. CONSCLUSIONS: We believe that our preliminary data confirm the clinical importance of AAT deficiency in GPA patients and the need to screen for AAT deficiency alleles. The study is on-going.
No preview · Article · Jun 2013 · Pneumonologia i alergologia polska: organ Polskiego Towarzystwa Ftyzjopneumonologicznego, Polskiego Towarzystwa Alergologicznego, i Instytutu Gruzlicy i Chorob Pluc