Updates for c.91C>T:
2024-10-14 Class updated from VUS4 to likely benign
2024-10-20 Class updated from likely benign to non disease-causing
2024-12-09 Variant classified as non-disease-causing on the basis of epidemiological data (in particular high frequency in the general population), the number and type of diagnosis for patients reported in CFTR-France and functional data




Variant NM_000492.4:c.91C>T


Variant details:
Name NM_000492.4:c.91C>T
Protein name NP_000483.3:p.(Arg31Cys)
Genomic name (hg19)     chr7:g.117144344C>T    UCSC    
Genomic name (hg38) chr7:g.117504290C>T    UCSC
#Exon/intron exon 2
Legacy Name R31C ; 223C/T
Class non disease-causing
WT sequence AATTTTGAGGAAAGGATACAGACAG C GCCTGGAATTGTCAGACATATACCA
Mutant sequence AATTTTGAGGAAAGGATACAGACAG T GCCTGGAATTGTCAGACATATACCA

Other databases:
860
1001
 dbSNP
rs1800073



Pathogenicity predictors:

Functional studies:


Reference PMID Splicing mRNA level Maturation Localization Channel fonction (Cl-) Bicarbonate
Jurkuvenaite et al, 2006 16339147 ✓ ✓ ✓
Sosnay et al, 2013 23974870 ✓ ✓


« ✓ » indicates the type of analysis performed and not the results



2 individuals carrying this variant are reported in CFTR-NGS catalogue


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

TOTAL NUMBER OF PATIENTS 19
Asymptomatic compound heterozygote 4
CF 2
CFTR-RD12
  • Bronchiectasis  3
  • CBAVD  2
  • Other  1
  • Pancreatitis  6
Pending 1




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

Detailed genotypes:
Phenotype Patient ID Variant status Additional variants
Asymptomatic compound heterozygote 922heterozygote
Asymptomatic compound heterozygote 4579heterozygoteVUS1 - Trans
Asymptomatic compound heterozygote 5525heterozygoteVUS3- Undef
Asymptomatic compound heterozygote 965heterozygoteCFTR-RD-causing - Trans
Pancreatitis 5115heterozygoteVUS3- Undef
Pancreatitis 5894heterozygoteCFTR-RD-causing- Undef
Pancreatitis 5108heterozygoteCF-causing- Undef
Pancreatitis 1851heterozygoteCFTR-RD-causing - Trans
Pancreatitis 1168heterozygote
Pancreatitis 964heterozygoteCFTR-RD-causing - Trans
CF 2546heterozygoteCF-causing- Undef
CF 975heterozygoteCF-causing- Undef
Bronchiectasis 4253heterozygote
Bronchiectasis 2590heterozygoteCF-causing- Undef
Bronchiectasis 5043heterozygoteCF-causing- Undef
CBAVD 2400heterozygote
CBAVD 6175heterozygoteCFTR-RD-causing - Cis
CF-causing - Trans
Pending 3089heterozygote
Other 6157heterozygoteCF-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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