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Severe alpha-1 antitrypsin deficiency in composite heterozygotes inheriting a new splicing mutation QOMadrid.

ABSTRACT: BACKGROUND: Severe Alpha-1 Antitrypsin (AAT) deficiency is a hereditary condition caused by mutations in the SERPINA1 gene, which predisposes to lung emphysema and liver disease. It is usually related to PI*Z alleles, and less frequent to rare and null (QO) alleles. Null-AAT alleles represent the end of a continuum of variants associated with profound AAT deficiency and extremely increased risk of emphysema. METHODS: A family with severe AAT deficiency was analyzed to achieve genetic diagnosis. The complete exons and introns of the SERPINA1 gene were sequenced and transcriptional analysis by RT-PCR was performed to characterize the effect of splicing variants found in the patients. In addition, a minigene MGserpa1_ex1b-1c was cloned into the pSAD vector to in vitro investigate the independent impact of variants on splicing process. RESULTS: We report a new identified null allele (PI*QOMadrid) in two adult siblings with practically no detectable serum AAT. The PI*QOMadrid allele consist of a duplication of the thymine (T) in position +2 of the donor splice site of exon 1C (+2dupT). In these two subjects, PI*QOMadrid occurred in compound heterozygote combination with the previously described variant PI*QOPorto. Both QOMadrid and QOPorto variants are located very close together in a regulatory region of the SERPINA1 gene. Analysis of transcripts revealed that QOMadrid variant prevented the expression of transcripts from exon 1C, and then normally spliced RNA products are not expected in the liver of these patients. In addition, aberrant splicing patterns of both variants were clearly distinguished and quantified by functional in vitro assays lending further support to their pathogenicity. CONCLUSION: Finding pathogenic mutations in non-coding regions of the SERPINA1 highlight the importance that regulatory regions might have in the disease. Regulatory regions should be seriously considered in discordant cases with severe AAT deficiency where no coding mutations were found.

SUBMITTER: Lara B

PROVIDER: S-EPMC4194419 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Severe alpha-1 antitrypsin deficiency in composite heterozygotes inheriting a new splicing mutation QOMadrid.

Lara Beatriz B Martínez Maria Teresa MT Blanco Ignacio I Hernández-Moro Cristina C Velasco Eladio A EA Ferrarotti Ilaria I Rodriguez-Frias Francisco F Perez Laura L Vazquez Irene I Alonso Javier J Posada Manuel M Martínez-Delgado Beatriz B

Respiratory research 20141007

<h4>Background</h4>Severe Alpha-1 Antitrypsin (AAT) deficiency is a hereditary condition caused by mutations in the SERPINA1 gene, which predisposes to lung emphysema and liver disease. It is usually related to PI*Z alleles, and less frequent to rare and null (QO) alleles. Null-AAT alleles represent the end of a continuum of variants associated with profound AAT deficiency and extremely increased risk of emphysema.<h4>Methods</h4>A family with severe AAT deficiency was analyzed to achieve geneti ...[more]

PMID: 25287719

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Project description:BackgroundPatients with alpha-1 antitrypsin deficiency (AATD) exhibit dysregulated inflammatory responses and a predilection for autoimmunity. While the adverse event (AE) profiles of COVID-19 vaccines in several chronic inflammatory conditions are now available, safety and tolerability data for patients with severe AATD have yet to be described. The feasibility of coadministering vaccines against COVID-19 and influenza in this population is similarly unclear.MethodsWe conducted a prospective study of 170 patients with Pi*ZZ genotype AATD receiving their initial vaccination series with ChAdOx1 nCoV-19 (AstraZeneca). Patients were monitored clinically for AEs over the week that followed their first and second doses. In parallel, we conducted the same assessments in patients with Pi*MM genotype chronic obstructive pulmonary disease (COPD) (n=160) and Pi*MM individuals without lung disease (n=150). The Pi*ZZ cohort was subsequently followed through 2 consecutive mRNA-based booster vaccines (monovalent and bivalent BNT162b2, Pfizer/BioNTech). To assess the safety of combined vaccination against COVID-19 and influenza, the quadrivalent influenza vaccine was administered to participants attending for their second COVID-19 booster vaccination, either on the same day or following a 1-week interval.ResultsPi*ZZ AATD participants did not display increased AEs compared to Pi*MM COPD or Pi*MM non-lung disease controls. Although unexpected and serious vaccine-associated AEs did occur, the majority of AEs experienced across the 3 groups were mild and self-limiting. The AATD demographic at highest risk for AEs (especially systemic and prolonged AEs) was young females. No increase in AE risk was observed in patients with established emphysema, sonographic evidence of liver disease, or in those receiving intravenous augmentation therapy. AE incidence declined sharply following the initial vaccine series. Same-day coadministration of the COVID-19 mRNA bivalent booster vaccine and the annual influenza vaccine did not result in increased AEs compared to sequential vaccines 1 week apart.ConclusionsDespite their pro-inflammatory state, patients with severe AATD are not at increased risk of AEs or serious AEs compared to patients with nonhereditary COPD and patients without lung disease. Same-day coadministration of COVID-19 booster vaccines with the annual influenza vaccine is feasible, safe, and well-tolerated in this population.

Project description:BACKGROUND:Alpha-1-antitrypsin (AAT) deficiency (AATD) of Z, Mmalton, Siiyama type is associated with liver storage of the mutant proteins and liver disease. The Z variant can be diagnosed on isoelectric focusing (IEF) while Mmalton and Siiyama may be missed or misdiagnosed with this technique. Therefore, molecular analysis is mandatory for their characterization. In particular, that holds true for the Mmalton variant as on IEF profile it resembles the wild M2 subtype. METHODS:This is a retrospective analysis involving review of medical records and of liver biopsy specimens from a series of Mmalton, Z and Siiyama Alpha-1-antitrypsin deficiency patients. The review has been implemented by additional histological stains, electron microscopic observations and 3-D modeling studies of the sites of the mutations. RESULTS:Z, Mmalton and Siiyama liver specimen contained characteristic intrahepatocytic PAS-D globules. The globules differed in the three variants as only Mmalton cases showed dark basophilic precipitates within the AAT inclusions. The precipitates were visualized in haematoxylin-eosin (H.E.) stained preparations and corresponded to calcium precipitates as demonstrated by von Kossa staining. On immunohistochemistry, ZAAT inclusions were stained by polyclonal as well as monoclonal noncommercial anti-AAT antibody (AZT11), whilst Mmalton and Siiyama inclusion bodies remained negative with the monoclonal anti-Z antibody. 3-D protein analysis allowed to predict more severe misfolding of the Mmalton molecule as compared to Z and Siiyama that could trigger anomalous interaction with endoplasmic reticulum chaperon proteins, namely calcium binding proteins. CONCLUSIONS:Mmalton AAT inclusion bodies contain calcium precipitates inside them that allow the differential diagnosis with Siiyama and ZAAT inclusions in routine histological sections. The study has confirmed the specificity of the monoclonal AZT11 for the Z mutant. Thus, the combination of these two features is crucial for the distinction between the three variants and for predicting the genotype, whose confirmation would definitely require molecular analysis. Our study provides new data on the pathomorphogenesis of Mmalton inclusion bodies whose mineralization could play a central role in disease pathogenesis of Mmalton that is distinct from the Z and Siiyama variants. Calcium is known to be a major effector of cell death either via the increased intracellular concentration or the alteration of homeostasis.

Project description:Patients with severe alpha-1 antitrypsin deficiency (AATD) are at increased risk for the development of chronic obstructive pulmonary disease (COPD), particularly if they smoke. This, coupled with their predilection for dysregulated inflammation and autoimmunity, makes affected individuals priority candidates for vaccination against coronavirus disease 2019 (COVID-19). To promote vaccine uptake effectively, an understanding of the factors motivating people to proceed with vaccination is essential. The attitudes of patients with AATD towards COVID-19 vaccination have yet to be described. We prospectively studied 170 Pi*ZZ genotype AATD patients, 150 patients with nonhereditary (Pi*MM genotype) COPD and 140 Pi*MM genotype individuals without lung disease receiving first-dose vaccination with ChAdOx1 nCoV-19 (AstraZeneca). Patient attitudes towards vaccination and motivations for getting vaccinated were assessed at the time of the vaccine being offered. Following completion of the 2-dose vaccine series, Pi*ZZ patients were then re-assessed regarding their attitudes towards booster vaccination. The most common primary motivation for accepting vaccination in Pi*ZZ participants ≥50 years old was a fear of illness or death from COVID-19. In contrast, Pi*ZZ patients <50 years most often cited a desire to socialize. The motivation pattern of younger Pi*ZZ AATD patients was similar to that of non-deficient individuals of comparable age, whereas older Pi*ZZ individuals were more closely aligned with Pi*MM COPD and differed from age-matched controls without lung disease. When considering booster vaccination, Pi*ZZ patients were increasingly motivated by a desire to reacquire social freedoms. A desire to reduce the risk of transmission was not a prominent consideration in any of the groups studied. The most commonly cited reason for booster hesitancy was a lack of incentive, given that no additional social freedoms were available to triple-vaccinated individuals compared to those who were double-vaccinated at the time. Taken together, these data may inform policymakers attempting to promote vaccine uptake among patients with AATD.

Project description:Background: Alpha-1 antitrypsin deficiency (A1ATD) is a progressive lung disease caused by inherited pathogenic variants in the SERPINA1 gene. However, their actual role in maintenance of structural and functional characteristics of the corresponding α-1 anti-trypsin (A1AT) protein is not well characterized. Methods: The A1ATD causative SERPINA1 missense variants were initially collected from variant databases, and they were filtered based on their pathogenicity potential. Then, the tertiary protein models were constructed and the impact of individual variants on secondary structure, stability, protein-protein interactions, and molecular dynamic (MD) features of the A1AT protein was studied using diverse computational methods. Results: We identified that A1ATD linked SERPINA1 missense variants like F76S, S77F, L278P, E288V, G216C, and H358R are highly deleterious as per the consensual prediction scores of SIFT, PolyPhen, FATHMM, M-CAP and REVEL computational methods. All these variants were predicted to alter free energy dynamics and destabilize the A1AT protein. These variants were seen to cause minor structural drifts at residue level (RMSD = <2Å) of the protein. Interestingly, S77F and L278P variants subtly alter the size of secondary structural elements like beta pleated sheets and loops. The residue level fluctuations at 100 ns simulation confirm the highly damaging structural consequences of all the six missense variants on the conformation dynamics of the A1AT protein. Moreover, these variants were also predicted to cause functional deformities by negatively impacting the binding energy of A1AT protein with NE ligand molecule. Conclusion: This study adds a new computational biology dimension to interpret the genotype-protein phenotype relationship between SERPINA1 pathogenic variants with its structural plasticity and functional behavior with NE ligand molecule contributing to the Alpha-1-antitrypsin deficiency. Our results support that A1ATD complications correlates with the conformational flexibility and its propensity of A1AT protein polymerization when misfolded.

Dataset Information

Severe alpha-1 antitrypsin deficiency in composite heterozygotes inheriting a new splicing mutation QOMadrid.

Publications

Severe alpha-1 antitrypsin deficiency in composite heterozygotes inheriting a new splicing mutation QOMadrid.

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