rs1554380828

Variant names:

• chr7-117536676-A-C
• rs1554380828
• NM_000492.4:c.869+3A>C

Your query was ambiguous. Multiple possible variants found:

• chr7-117536676-A-C
• chr7-117536676-A-T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000492.4(CFTR):​c.869+3A>C variant causes a splice region, intron change. The variant allele was found at a frequency of 0.000000686 in 1,457,308 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: CFTR NM_000492.4 splice_region, intron
• Scores: Splicing: ADA: 0.9997
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.83
• Publications: 0 publications found

Genes affected

CFTR (HGNC:1884): (CF transmembrane conductance regulator) This gene encodes a member of the ATP-binding cassette (ABC) transporter superfamily. The encoded protein functions as a chloride channel, making it unique among members of this protein family, and controls ion and water secretion and absorption in epithelial tissues. Channel activation is mediated by cycles of regulatory domain phosphorylation, ATP-binding by the nucleotide-binding domains, and ATP hydrolysis. Mutations in this gene cause cystic fibrosis, the most common lethal genetic disorder in populations of Northern European descent. The most frequently occurring mutation in cystic fibrosis, DeltaF508, results in impaired folding and trafficking of the encoded protein. Multiple pseudogenes have been identified in the human genome. [provided by RefSeq, Aug 2017]

CFTR Gene-Disease associations (from GenCC):

• cystic fibrosis

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, Orphanet
• congenital bilateral absence of vas deferens

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hereditary chronic pancreatitis

  Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CFTR	NM_000492.4	c.869+3A>C		splice_region_variant, intron_variant	Intron 7 of 26	ENST00000003084.11	NP_000483.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CFTR	ENST00000003084.11	c.869+3A>C		splice_region_variant, intron_variant	Intron 7 of 26	1	NM_000492.4	ENSP00000003084.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.86e-7 AC: 1 AN: 1457308 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 725130

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33408

American (AMR) AF: 0.00 AC: 0 AN: 44662

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26042

East Asian (EAS) AF: 0.00 AC: 0 AN: 39522

South Asian (SAS) AF: 0.00 AC: 0 AN: 86114

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51648

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5690

European-Non Finnish (NFE) AF: 9.01e-7 AC: 1 AN: 1109948

Other (OTH) AF: 0.00 AC: 0 AN: 60274

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Mar 29, 2016

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: The c.689+3A>C variant in CFTR gene is an intronic change that alters a conserved nucleotide. 5/5 in silico tools via Alamut predict this variant to affect a normal splicing pattern, however, these predictions have yet to be confirmed by in vitro/in vivo functional studies. Another variant at this position, c.689+3A>T, that was identified in CF pt and pt, presented with hypochloraemic alkalosis, displayed similar in silico pattern and was shown to lead to alternative splicing and complete skipping of exon 7. The variant of interest has not, to our knowledge, been reported in the affected individuals, nor has it been cited by reputable clinical laboratories/diagnostic centers, however was identified in one affected individual in whom presence of F508del was also confirmed. The variant is absent from the large control population dataset of ExAC (0/~114434 chromosomes). Taken together, the variant was classified as VUS-possibly pathogenic and reported by Integrated Genetics as "likely clinically significant" until new information becomes available. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.26
CADD	Benign	20
DANN	Benign	0.97
PhyloP100		4.8

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.92
SpliceAI score (max)		0.80		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.24		Position offset: 24
DS_DL_spliceai		0.80		Position offset: -3

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1554380828; hg19: chr7-117176730;