Identification of new F8 deep intronic variations in patients with haemophilia A.
Haemophilia
; 26(5): 847-854, 2020 Sep.
Article
em En
| MEDLINE
| ID: mdl-32812322
ABSTRACT
INTRODUCTION:
With current molecular diagnosis, about 1 to 5% of haemophilia A (HA) patients remain genetically unresolved. In these cases, deep intronic variation or structural variation disrupting the F8 gene could be causal.AIM:
To identify the causal variation in four genetically unresolved mild-to-severe HA patients using an F8 mRNA analysis approach.METHODS:
Ectopic F8 mRNA analysis was performed in four unrelated HA patients. An in vitro minigene assay was performed in order to confirm the deleterious splicing impact of each variation identified.RESULTS:
In all probands, mRNA analysis revealed an aberrant splicing pattern, and sequencing of the corresponding intronic region found a deep intronic substitution. Two of these were new variations c.2113+601G>A and c.1443+602A>G, while the c.143+1567A>G, found in two patients, has previously been reported. The c.1443+602A>G and the c.143+1567A>G variants both led to the creation of a de novo acceptor or donor splice site, respectively. Moreover, the c.143+1567A>G was found in 3/6 patients with genetically unresolved moderate HA registered in our laboratory. Haplotype analysis performed in all patients carrying the c.143+1567A>G variation suggests that this variation could be a recurrent variation. The c.2113+601G>A led to the exonization of a 122-bp antisense AluY element by increasing the strength of a pre-existing cryptic 5' splice site. For each point variation, in vitro splicing analysis confirmed its deleterious impact on splicing of the F8 transcript.CONCLUSION:
We identified three deep intronic variations, leading to an aberrant mRNA splicing process as HA causing variation.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Íntrons
/
Predisposição Genética para Doença
/
Hemofilia A
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Female
/
Humans
/
Male
Idioma:
En
Revista:
Haemophilia
Assunto da revista:
HEMATOLOGIA
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
França