Minigene Splicing Assays and Long-Read Sequencing to Unravel Pathogenic Deep-Intronic Variants in PAX6 in Congenital Aniridia.
Int J Mol Sci
; 24(2)2023 Jan 13.
Article
en En
| MEDLINE
| ID: mdl-36675087
ABSTRACT
PAX6 haploinsufficiency causes aniridia, a congenital eye disorder that involves the iris, and foveal hypoplasia. Comprehensive screening of the PAX6 locus, including the non-coding regions, by next-generation sequencing revealed four deep-intronic variants with potential effects on pre-RNA splicing. Nevertheless, without a functional analysis, their pathogenicity could not be established. We aimed to decipher their impact on the canonical PAX6 splicing using in vitro minigene splicing assays and nanopore-based long-read sequencing. Two multi-exonic PAX6 constructs were generated, and minigene assays were carried out. An aberrant splicing pattern was observed for two variants in intron 6, c.357+136G>A and c.357+334G>A. In both cases, several exonization events, such as pseudoexon inclusions and partial intronic retention, were observed due to the creation or activation of new/cryptic non-canonical splicing sites, including a shared intronic donor site. In contrast, two variants identified in intron 11, c.1032+170A>T and c.1033-275A>C, seemed not to affect splicing processes. We confirmed the high complexity of alternative splicing of PAX6 exon 6, which also involves unreported cryptic intronic sites. Our study highlights the importance of integrating functional studies into diagnostic algorithms to decipher the potential implication of non-coding variants, usually classified as variants of unknown significance, thus allowing variant reclassification to achieve a conclusive genetic diagnosis.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Aniridia
/
Empalme del ARN
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Int J Mol Sci
Año:
2023
Tipo del documento:
Article
País de afiliación:
España