4-15473257-T-G

Variant names:

• chr4-15473257-T-G
• rs568331446
• NM_001378615.1:c.-18-2658T>G

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_001080522.2(CC2D2A):​c.-19+2T>G variant causes a splice donor, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000788 in 152,286 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: 𝑓 0.000079 (0 hom., cov: 32)
• Consequence: CC2D2A NM_001080522.2 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.256

Genes affected

CC2D2A (HGNC:29253): (coiled-coil and C2 domain containing 2A) This gene encodes a coiled-coil and calcium binding domain protein that appears to play a critical role in cilia formation. Mutations in this gene cause Meckel syndrome type 6, as well as Joubert syndrome type 9. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Sep 2009]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 7, offset of 4, new splice context is: gaaGTatgt. 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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CC2D2A	NM_001378615.1	c.-18-2658T>G		intron_variant	Intron 1 of 36	ENST00000424120.6	NP_001365544.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CC2D2A	ENST00000424120.6	c.-18-2658T>G		intron_variant	Intron 1 of 36	5	NM_001378615.1	ENSP00000403465.1

Frequencies

GnomAD3 genomes AF: 0.0000789 AC: 12 AN: 152168 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000196

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000132

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 0

GnomAD4 genome AF: 0.0000788 AC: 12 AN: 152286 Hom.: 0 Cov.: 32 AF XY: 0.0000672 AC XY: 5 AN XY: 74458

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.000196

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000132

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000693 Hom.: 0

Bravo AF: 0.0000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

May 13, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis is inconclusive as to whether the variant alters gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown.; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.78
CADD	Benign	6.0
DANN	Benign	0.79

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Benign	0.68
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs568331446; hg19: chr4-15474881;