Splicing analysis of SLC40A1 missense variations and contribution to hemochromatosis type 4 phenotypes.
Blood Cells Mol Dis
; 87: 102527, 2021 03.
Article
in En
| MEDLINE
| ID: mdl-33341511
ABSTRACT
Hemochromatosis type 4, or ferroportin disease, is considered as the second leading cause of primary iron overload after HFE-related hemochromatosis. The disease, which is predominantly associated with missense variations in the SLC40A1 gene, is characterized by wide clinical heterogeneity. We tested the possibility that some of the reported missense mutations, despite their positions within exons, cause splicing defects. Fifty-eight genetic variants were selected from the literature based on two criteria a precise description of the nucleotide change and individual evidence of iron overload. The selected variants were investigated by different in silico prediction tools and prioritized for midigene splicing assays. Of the 15 variations tested in vitro, only two were associated with splicing changes. We confirm that the c.1402G>A transition (p.Gly468Ser) disrupts the exon 7 donor site, leading to the use of an exonic cryptic splicing site and the generation of a truncated reading frame. We observed, for the first time, that the p.Gly468Ser substitution has no effect on the ferroportin iron export function. We demonstrate alternative splicing of exon 5 in different cell lines and show that the c.430A>G (p.Asn144Asp) variant promotes exon 5 inclusion. This could be part of a gain-of-function mechanism. We conclude that splicing mutations rarely contribute to hemochromatosis type 4 phenotypes. An in-depth investigation of exon 5 auxiliary splicing sequences may help to elucidate the mechanism by which splicing regulatory proteins regulate the production of the full length SLC40A1 transcript and to clarify its physiological importance.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Alternative Splicing
/
Mutation, Missense
/
Cation Transport Proteins
/
Hemochromatosis
Type of study:
Prognostic_studies
Limits:
Humans
Language:
En
Journal:
Blood Cells Mol Dis
Journal subject:
HEMATOLOGIA
Year:
2021
Document type:
Article
Affiliation country: