rs386833758

Positions:

• chr4-15580089-T-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_001378615.1(CC2D2A):​c.3893T>A​(p.Val1298Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,638 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: CC2D2A NM_001378615.1 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 7.73

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 Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.911

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CC2D2A	NM_001378615.1	c.3893T>A	p.Val1298Asp	missense_variant	30/37	ENST00000424120.6
CC2D2A	NM_001080522.2	c.3893T>A	p.Val1298Asp	missense_variant	31/38
CC2D2A	NM_001378617.1	c.3746T>A	p.Val1249Asp	missense_variant	28/35

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CC2D2A	ENST00000424120.6	c.3893T>A	p.Val1298Asp	missense_variant	30/37	5	NM_001378615.1	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461638 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727106

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Meckel syndrome, type 6 Pathogenic:1

Likely pathogenic, no assertion criteria provided

literature only

Juha Muilu Group; Institute for Molecular Medicine Finland (FIMM)

-

- -

Meckel-Gruber syndrome;C0431399:Familial aplasia of the vermis Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 15, 2021

This variant is not present in population databases (ExAC no frequency). This sequence change replaces valine with aspartic acid at codon 1298 of the CC2D2A protein (p.Val1298Asp). The valine residue is highly conserved and there is a large physicochemical difference between valine and aspartic acid. This missense change has been observed in individual(s) with clinical features of Meckel-Gruber syndrome (PMID: 21068128, 23351400). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt CC2D2A protein function. ClinVar contains an entry for this variant (Variation ID: 56310). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.79
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.77	D;D
Eigen	Uncertain	0.66
Eigen_PC	Uncertain	0.58
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.97	D;.
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.91	D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.2	M;M
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.64	T
PROVEAN	Pathogenic	-5.5	D;D
REVEL	Pathogenic	0.89
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.96
MutPred		0.57		Loss of sheet (P = 0.0037);Loss of sheet (P = 0.0037);
MVP		0.86
MPC		0.34
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.92
gMVP		0.93

Splicing

Name	Calibrated prediction	Score	Prediction
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: rs386833758; hg19: chr4-15581712;