SERPING1 Dotaz Zobrazit nápovědu
Mutations in the C1 inhibitor (C1INH) encoding gene, SERPING1, are associated with hereditary angioedema (HAE) which manifests as recurrent submucosal and subcutaneous edema episodes. The major C1INH function is the complement system inhibition, preventing its spontaneous activation. The presented study is focused on SERPING1 exon 3, an alternative and extraordinarily long exon (499 bp). Endogenous expression analysis performed in the HepG2, human liver, and human peripheral blood cells revealed several exon 3 splicing variants alongside exon inclusion: a highly prevalent exon skipping variant and less frequent +38 and -15 variants with alternative 3' splice sites (ss) located 38 and 15 nucleotides downstream and upstream from the authentic 3' ss, respectively. An exon skipping variant introducing a premature stop codon, represented nearly one third of all splicing variants and surprisingly appeared not to be degraded by NMD. The alternative -15 3' ss was used to a small extent, although predicted to be extremely weak. Its use was shown to be independent of its strength and highly sensitive to any changes in the surrounding sequence. -15 3' ss seems to be co-regulated with the authentic 3' ss, whose use is dependent mainly on its strength and less on the presence of intronic regulatory motifs. Subtle SERPING1 exon 3 splicing regulation can contribute to overall C1INH plasma levels and HAE pathogenesis.
- MeSH
- alternativní sestřih genetika MeSH
- buněčné jádro genetika MeSH
- buňky Hep G2 MeSH
- exony genetika MeSH
- inhibiční protein komplementu C1 genetika MeSH
- lidé MeSH
- malá interferující RNA metabolismus MeSH
- místa sestřihu RNA genetika MeSH
- mutace genetika MeSH
- nonsense mediated mRNA decay genetika MeSH
- sekvence nukleotidů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
PURPOSE: Hereditary angioedema (HAE) is a rare autosomal dominant life-threatening disease characterized by low levels of C1 inhibitor (type I HAE) or normal levels of ineffective C1 inhibitor (type II HAE), typically occurring as a consequence of a SERPING1 mutation. In some cases, a causal mutation remains undetected after using a standard molecular genetic analysis. RESULTS: Here we show a long methodological way to the final discovery of c.1029 + 384A > G, a novel deep intronic mutation in intron 6 which is responsible for HAE type I in a large family and has not been identified by a conventional diagnostic approach. This mutation results in de novo donor splice site creation and subsequent pseudoexon inclusion, the mechanism firstly described to occur in SERPING1 in this study. We additionally discovered that the proximal part of intron 6 is a region potentially prone to pseudoexon-activating mutations, since natural alternative exons and additional cryptic sites occur therein. Indeed, we confirmed the existence of at least two different alternative exons in this region not described previously. CONCLUSIONS: In conclusion, our results suggest that detecting aberrant transcripts, which are often low abundant because of nonsense-mediated decay, requires a modified methodological approach. We suggest SERPING1 intron 6 sequencing and/or tailored mRNA analysis to be routinely used in HAE patients with no mutation identified in the coding sequence.
- MeSH
- dítě MeSH
- dospělí MeSH
- exony genetika MeSH
- hereditární angioedém, typy I a II genetika MeSH
- inhibiční protein komplementu C1 genetika MeSH
- introny genetika MeSH
- lidé středního věku MeSH
- lidé MeSH
- místa sestřihu RNA genetika MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mutace genetika MeSH
- mutační analýza DNA metody MeSH
- rodokmen MeSH
- senioři MeSH
- splicing proteinů genetika MeSH
- Check Tag
- dítě MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Hereditary angioedema due to C1 inhibitor deficiency (C1-INH-HAE) is a rare and life-threatening condition characterized by recurrent localized edema. We conducted a systematic screening of SERPING1 defects in a cohort of 207 Czech patients from 85 families with C1-INH-HAE. Our workflow involved a combined strategy of sequencing extended to UTR and deep intronic regions, advanced in silico prediction tools, and mRNA-based functional assays. This approach allowed us to detect a causal variant in all families except one and to identify a total of 56 different variants, including 5 novel variants that are likely to be causal. We further investigated the functional impact of two splicing variants, namely c.550 + 3A > C and c.686-7C > G using minigene assays and RT-PCR mRNA analysis. Notably, our cohort showed a considerably higher proportion of detected splicing variants compared to other central European populations and the LOVD database. Moreover, our findings revealed a significant association between HAE type 1 missense variants and a delayed HAE onset when compared to null variants. We also observed a significant correlation between the presence of the SERPING1 variant c.-21 T > C in the trans position to causal variants and the frequency of attacks per year, disease onset, as well as Clinical severity score. Overall, our study provides new insights into the genetic landscape of C1-INH-HAE in the Czech population, including the identification of novel variants and a better understanding of genotype-phenotype correlations. Our findings also highlight the importance of comprehensive screening strategies and functional analyses in improving the C1-INH-HAE diagnosis and management.
- MeSH
- hereditární angioedémy * diagnóza epidemiologie genetika MeSH
- inhibiční protein komplementu C1 * genetika MeSH
- lidé MeSH
- messenger RNA MeSH
- sestřih RNA MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Hereditary angioedema with C1 Inhibitor deficiency (C1-INH-HAE) is caused by a constellation of variants of the SERPING1 gene (n = 809; 1,494 pedigrees), accounting for 86.8% of HAE families, showing a pronounced mutagenic liability of SERPING1 and pertaining to 5.6% de novo variants. C1-INH is the major control serpin of the kallikrein-kinin system (KKS). In addition, C1-INH controls complement C1 and plasminogen activation, both systems contributing to inflammation. Recognizing the failed control of C1s protease or KKS provides the diagnosis of C1-INH-HAE. SERPING1 variants usually behave in an autosomal-dominant character with an incomplete penetrance and a low prevalence. A great majority of variants (809/893; 90.5%) that were introduced into online database have been considered as pathogenic/likely pathogenic. Haploinsufficiency is a common feature in C1-INH-HAE where a dominant-negative variant product impacts the wild-type allele and renders it inactive. Small (36.2%) and large (8.3%) deletions/duplications are common, with exon 4 as the most affected one. Point substitutions with missense variants (32.2%) are of interest for the serpin structure-function relationship. Canonical splice sites can be affected by variants within introns and exons also (14.3%). For noncanonical sequences, exon skipping has been confirmed by splicing analyses of patients' blood-derived RNAs (n = 25). Exonic variants (n = 6) can affect exon splicing. Rare deep-intron variants (n = 6), putatively acting as pseudo-exon activating mutations, have been characterized as pathogenic. Some variants have been characterized as benign/likely benign/of uncertain significance (n = 74). This category includes some homozygous (n = 10) or compound heterozygous variants (n = 11). They are presenting with minor allele frequency (MAF) below 0.00002 (i.e., lower than C1-INH-HAE frequency), and may be quantitatively unable to cause haploinsufficiency. Rare benign variants could contribute as disease modifiers. Gonadal mosaicism in C1-INH-HAE is rare and must be distinguished from a de novo variant. Situations with paternal or maternal disomy have been recorded (n = 3). Genotypes must be interpreted with biological investigation fitting with C1-INH expression and typing. Any SERPING1 variant reminiscent of the dysfunctional phenotype of serpin with multimerization or latency should be identified as serpinopathy.
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
BACKGROUND: Hereditary angioedema (HAE) is a rare autosomal dominant genetic disease characterised by acute episodes of non-pruritic skin and submucosal swelling caused by increase in vascular permeability. OBJECTIVE: Here we present the first complex analysis of the National HAE Slovakian cohort with the detection of 12 previously un-published genetic variants in SERPING1 gene. METHODS: In patients diagnosed with hereditary angioedema caused by deficiency or dysfunction of C1 inhibitor (C1-INH-HAE) based on clinical manifestation and complement measurements, SERPING1 gene was tested by DNA sequencing (Sanger sequencing/massive parallel sequencing) and/or multiplex ligation-dependent probe amplification for detection of large rearrangements. RESULTS: The Slovakian national cohort consisted of 132 living patients with confirmed HAE. We identified 51 index cases (32 families, 19 sporadic patients/112 adults, 20 children). One hundred seventeen patients had HAE caused by deficiency of C1 inhibitor (C1-INH-HAE-1) and 15 patients had HAE caused by dysfunction of C1 inhibitor (C1-INH-HAE-2). The prevalence of HAE in Slovakia has recently been calculated to 1:41 280 which is higher than average calculated prevalence. The estimated incidence was 1:1360 000. Molecular-genetic testing of the SERPING1 gene found 22 unique causal variants in 26 index cases, including 12 previously undescribed and unreported. CONCLUSION: The first complex report about epidemiology and genetics of the Slovakian national HAE cohort expands the knowledge of the C1-INH-HAE genetics. Twelve novel causal variants were present in the half of the index cases. A higher percentage of inframe variants comparing to other studies was observed. Heterozygous deletion of exon 3 found in a large C1-INH-HAE-1 family probably causes the dysregulation of the splicing isoforms balance and leads to the decrease of full-length C1-INH level.
- Publikační typ
- časopisecké články MeSH
Závěrečná zpráva o řešení grantu Agentury pro zdravotnický výzkum MZ ČR
nestr.
Hereditary angioedema (HAE) is one of bradykinin-associated angioedema characterized by recurrent attacks of swelling. It is characterized by decreased level and/or function of C1 inhibitor (SERPING1), which results in local bradykinin overproduction and subsequent angioedema development. The severity of HAE in terms of frequency and extent of attacks varies from very mild to very serious even in families with the same SERPING1 mutation, but the genetic determination of this heterogeneity remains to be clarified. We would like to elucidate which genetic factors largely contribute to this variability. We will determine genetic background of patients with diverse severity of HAE in 70 genes associated with bradykinin function using targeted DNA-seq. Another explanation labours with disrupted regulation of gene expression. Thus expression of selected genes (incl. SERPING1) in patients' macrophages will be determined using RNA-seq in a defined set of patients. Unique combination of transcriptomic and genomic approaches may improve our knowledge in all bradykinin-mediated angioedema.
Hereditární angioedém (HAE) je charakterizován rekurentími atakami otoků a je spojen se sníženou hladinou a/nebo funkcí C1 inhibitoru (SERPING1), což vede k lokální nadprodukci bradykininu a následnému rozvoji angioedému. I v rodinách se stejnou mutací v SERPING1 se HAE projevuje s různou závažností. Genetická determinace této různorodosti je dosud neobjasněna. Projekt by měl vysvětlit, které genetické faktory přispívají k této variabilitě. S použitím cílené DNA-seq bude charakterizováno celkem 70 genů souvisejících s funkčností bradykininu u pacientů s různou závažností HAE. Další faktory, které mohou způsobovat rozdílnost fenotypu se týkají regulace genové exprese, což nemusí souviset přímo se změnami sekvencí těchto genů, ale spíše se změnami regulačních faktorů, které ovlivňují expresi jednotlivých genů. Proto budeme pomocí cíleného RNA-seq sledovat expresi vybraných genů (včetně SERPING1) v monocytech/makrofázích u vybrané skupiny pacientů. Unikátní kombinace genomických i transkriptomických dat by měla přispět k porozumění mechanismu angioedémů a cílenější medikaci.
- Klíčová slova
- Next generation sequencing, genová exprese, gene expression, hereditary angioedema, hereditární angioedém, bradykinin, C1 inhibitor, SERPING1, asociační studie, sekvenování příští generace, bradykinin, c1 inhibitor, SERPING1, association study,
- NLK Publikační typ
- závěrečné zprávy o řešení grantu AZV MZ ČR
- MeSH
- farmakoterapie metody MeSH
- hereditární angioedémy * diagnóza terapie MeSH
- inhibiční protein komplementu C1 farmakologie terapeutické užití MeSH
- lidé MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH