CFTR-France

**Updates for c.1558G>A:**
2025-11-07	Class updated from VUS to likely benign (based on high frequency in the general population and patients data)

Variant details:
Name	NM_000492.4:c.1558G>A
Protein name	NP_000483.3:p.(Val520Ile)
Genomic name (hg19)	chr7:g.117199683G>A UCSC
Genomic name (hg38)	chr7:g.117559629G>A UCSC
#Exon/intron	exon 11
Legacy Name	V520I
Class	likely benign
WT sequence	CTATGATGAATATAGATACAGAAGC G TCATCAAAGCATGCCAACTAGAAGA
Mutant sequence	CTATGATGAATATAGATACAGAAGC A TCATCAAAGCATGCCAACTAGAAGA

Other databases:
	Not found	dbSNP rs77646904

No patient found in CFTR-NGS catalogue

2 patients carrying this variant are reported in CFTR-France:

TOTAL NUMBER OF PATIENTS	2
Asymptomatic compound heterozygote	2

Color code: non disease-causing < likely benign < VUS < likely pathogenic < disease-causing

Detailed genotypes:
Phenotype	Patient ID	Variant status	Additional variants
Asymptomatic compound heterozygote	372	heterozygote	CF-causing - Trans
Asymptomatic compound heterozygote	6556	heterozygote	CF-causing - Trans

Color code: non disease-causing < likely benign < VUS < likely pathogenic < disease-causing

CFTR variants are clustered into five groups (click here for more details about the classification of variants):

CF-causing: when in trans with another CF-causing mutation, will result in CF.
CFTR-RD causing: when in trans with a CF-causing mutation, will result in CFTR-related disorders (CFTR-RD) such as chronic pancreatitis, bronchiectasis, CRS-NP (chronic rhinosinusitis with or without nasal polyposis) or CBAVD (congenital absence of vas deferens), according to Bombieri C et al., 2011.
Varying clinical consequence: when in trans with another CF-causing mutation, can either result in CF or in a CFTR-RD.
Non disease-causing: when in trans with a CF-causing mutation, will not cause CF, nor CFTR-RD.
VUS (Variant of unknown clinical significance): unclassified because of insufficient data.

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