rs386833760

Positions:

Variant summary

Our verdict is Pathogenic. Variant got 20 ACMG points: 20P and 0B. PVS1PM2PP3_ModeratePP5_Very_Strong

The NM_001378615.1(CC2D2A):c.4179+1del variant causes a frameshift, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000767 in 1,578,048 control chromosomes in the GnomAD database, with no homozygous occurrence. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.00018 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000065 ( 0 hom. )

Consequence

CC2D2A
NM_001378615.1 frameshift, splice_region

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:13

Conservation

PhyloP100: 8.11

Variant links:

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]

CC2D2A links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 20 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

PP5

Variant 4-15587928-AG-A is Pathogenic according to our data. Variant chr4-15587928-AG-A is described in ClinVar as [Pathogenic]. Clinvar id is 56312.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr4-15587928-AG-A is described in Lovd as [Pathogenic]. Variant chr4-15587928-AG-A is described in Lovd as [Likely_pathogenic]. Variant chr4-15587928-AG-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	Effect	#exon/exons	MANE	Protein
CC2D2A	NM_001378615.1 linkuse as main transcript	c.4179+1del	frameshift_variant, splice_region_variant	32/37	ENST00000424120.6	NP_001365544.1
CC2D2A	NM_001080522.2 linkuse as main transcript	c.4179+1del	frameshift_variant, splice_region_variant	33/38		NP_001073991.2
CC2D2A	NM_001378617.1 linkuse as main transcript	c.4032+1del	frameshift_variant, splice_region_variant	30/35		NP_001365546.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CC2D2A	ENST00000424120.6 linkuse as main transcript	c.4179+1del		frameshift_variant, splice_region_variant	32/37	5	NM_001378615.1	ENSP00000403465	P1	Q9P2K1-4

Frequencies

GnomAD3 genomes

AF:

0.000184

AC:

AN:

152138

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00118

Gnomad ASJ

AF:

0.00173

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000931

AC:

AN:

247170

Hom.:

AF XY:

0.0000969

AC XY:

AN XY:

134098

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000294

Gnomad ASJ exome

AF:

0.000902

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000891

Gnomad OTH exome

AF:

0.000503

GnomAD4 exome

AF:

0.0000652

AC:

AN:

1425792

Hom.:

Cov.:

AF XY:

0.0000661

AC XY:

AN XY:

711328

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.000180

Gnomad4 ASJ exome

AF:

0.000929

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000528

Gnomad4 OTH exome

AF:

0.0000677

GnomAD4 genome

AF:

0.000184

AC:

AN:

152256

Hom.:

Cov.:

AF XY:

0.000295

AC XY:

AN XY:

74458

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00118

Gnomad4 ASJ

AF:

0.00173

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000588

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000565

Hom.:

Bravo

AF:

0.000283

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:13

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Meckel syndrome, type 6

Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jan 29, 2024	Variant summary: CC2D2A c.4179+1delG is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Three predict the variant abolishes a canonical 5' splicing donor site, and two predict the variant creates a cryptic 5' donor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 9.3e-05 in 247170 control chromosomes (gnomAD). This frequency is not significantly higher than estimated for a pathogenic variant in CC2D2A causing Meckel Syndrome Type 6 (9.3e-05 vs 0.0011), allowing no conclusion about variant significance. c.4179+1delG has been reported in the literature in individuals affected with Meckel Syndrome or Joubert Syndrome (Mougou-Zerelli_2009, Tallila_2009, Bachmann-Gagescu_2015). These data indicate that the variant is likely to be associated with disease. The following publications have been ascertained in the context of this evaluation (PMID: 19777577, 19466712, 26092869). ClinVar contains an entry for this variant (Variation ID: 56312). Based on the evidence outlined above, the variant was classified as pathogenic. -
Likely pathogenic, no assertion criteria provided	literature only	Juha Muilu Group; Institute for Molecular Medicine Finland (FIMM)	-	- -
Likely pathogenic, no assertion criteria provided	literature only	Juha Muilu Group; Institute for Molecular Medicine Finland (FIMM)	-	- -

not provided

Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Apr 27, 2022	Canonical splice site variant expected to result in aberrant splicing, although in the absence of functional evidence the actual effect of this sequence change is unknown.; This variant is associated with the following publications: (PMID: 31589614, 33486889, 19777577, 26092869, 19466712) -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Mar 14, 2016	- -

Joubert syndrome 9

Pathogenic:2

Pathogenic, criteria provided, single submitter	research	UW Hindbrain Malformation Research Program, University of Washington	Feb 23, 2015	- -
Pathogenic, criteria provided, single submitter	clinical testing	Centre for Mendelian Genomics, University Medical Centre Ljubljana	Jan 01, 2016	This variant was classified as: Pathogenic. The following ACMG criteria were applied in classifying this variant: PVS1,PS1,PM2,PP4. -

Meckel-Gruber syndrome;C0431399:Familial aplasia of the vermis

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 22, 2024

This sequence change affects a splice site in intron 33 of the CC2D2A gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in CC2D2A are known to be pathogenic (PMID: 19777577). This variant is present in population databases (rs386833761, gnomAD 0.09%). Disruption of this splice site has been observed in individual(s) with Joubert and/or Meckel-Gruber syndrome (PMID: 19777577, 26092869). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is also known as c.4179del. ClinVar contains an entry for this variant (Variation ID: 56312). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Joubert syndrome 9;C2676790:Meckel syndrome, type 6;C5436837:COACH syndrome 2;C5676970:Retinitis pigmentosa 93

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Feb 14, 2022

- -

Inborn genetic diseases

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 16, 2021

The c.4179+1delG variant results from a deletion of one nucleotide at position c.4179+1 and involves the canonical splice donor site after coding exon 31 of the CC2D2A gene. Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. Based on data from gnomAD, the - allele has an overall frequency of 0.01% (23/247170) total alleles studied. The highest observed frequency was 0.09% (9/9980) of Ashkenazi Jewish alleles. This mutation has been identified in 2 compound heterozygous individuals with Joubert syndrome as well as 2 compound heterozygous fetuses with Meckel syndrome (Mougou-Zerelli, 2009; Tallila, 2009; Bachmann-Gagescu, 2015). Based on the available evidence, this alteration is classified as pathogenic. -

Clubfoot;C0022680:Polycystic kidney disease;C0079924:Oligohydramnios;C0426790:Narrow chest;C4282400:Polydactyly, postaxial, type A1;C4551563:Microcephaly;C4551722:Encephalocele

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Centre for Mendelian Genomics, University Medical Centre Ljubljana

Jan 01, 2017

- -

Meckel-Gruber syndrome

Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Genetic Services Laboratory, University of Chicago

Sep 22, 2014

- -

Anencephaly;C0152427:Polydactyly;C3887499:Renal cyst

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Genetics Institute, Tel Aviv Sourasky Medical Center

May 12, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.83

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.83

Position offset: 1

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over