17-80099525-A-G

Variant names:

• chr17-80099525-A-G
• rs762664261
• NM_017950.4:c.3181-2A>G

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_017950.4(CCDC40):​c.3181-2A>G variant causes a splice acceptor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CCDC40 NM_017950.4 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 5.16

Genes affected

CCDC40 (HGNC:26090): (coiled-coil domain 40 molecular ruler complex subunit) This gene encodes a protein that is necessary for motile cilia function. It functions in correct left-right axis formation by regulating the assembly of the inner dynein arm and the dynein regulatory complexes, which control ciliary beat. Mutations in this gene cause ciliary dyskinesia type 15, a disorder due to defects in cilia motility. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2011]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 3.4, offset of 10, new splice context is: tcctacccggaacctttcAGaga. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-80099525-A-G is Pathogenic according to our data. Variant chr17-80099525-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 219643.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-80099525-A-G is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CCDC40	NM_017950.4	c.3181-2A>G		splice_acceptor_variant, intron_variant	Intron 19 of 19	ENST00000397545.9	NP_060420.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CCDC40	ENST00000397545.9	c.3181-2A>G		splice_acceptor_variant, intron_variant	Intron 19 of 19	5	NM_017950.4	ENSP00000380679.4
CCDC40	ENST00000574799.5	n.2718-2A>G		splice_acceptor_variant, intron_variant	Intron 15 of 15	1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Primary ciliary dyskinesia Pathogenic:1

Jul 28, 2015

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Likely Pathogenic. While this particular variant has not been reported in the literature, truncating variants in CCDC40 are known to be pathogenic (PMID:22693285). This sequence change affects an acceptor splice site in intron 19. It is expected to disrupt mRNA splicing and likely results in a disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	-0.020
CADD	Pathogenic	33
DANN	Uncertain	0.98
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.99	D
GERP RS		4.8

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.84
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.83		Position offset: 12
DS_AL_spliceai		1.0		Position offset: 2

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

Publications

LitVar

Other links and lift over

dbSNP: rs762664261; hg19: chr17-78073324;