Genetic Variant CCDC88C:p.Tyr38* (chr14-91416785-G-C) – ACMG Classification: Pathogenic (10 pts)

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1PM2

The NM_001080414.4(CCDC88C):c.114C>G(p.Tyr38*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000658 in 152,056 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. Y38Y) has been classified as Benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Consequence

CCDC88C
NM_001080414.4 stop_gained

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 0.461

Publications

15 publications found

Variant links:

Genes affected

CCDC88C (HGNC:19967): (coiled-coil domain containing 88C) This gene encodes a ubiquitously expressed coiled-coil domain-containing protein that interacts with the dishevelled protein and is a negative regulator of the Wnt signalling pathway. The protein encoded by this gene has a PDZ-domain binding motif in its C-terminus with which it interacts with the dishevelled protein. Dishevelled is a scaffold protein involved in the regulation of the Wnt signaling pathway. The Wnt signaling pathway plays an important role in embryonic development, tissue maintenance, and cancer progression. Mutations in this gene cause autosomal recessive, primary non-syndromic congenital hydrocephalus; a condition characterized by excessive accumulation of cerebrospinal fluid in the ventricles of the brain. [provided by RefSeq, Jan 2013]

CCDC88C Gene-Disease associations (from GenCC):

hydrocephalus, nonsyndromic, autosomal recessive 1
Inheritance: AR Classification: STRONG, MODERATE Submitted by: Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
spinocerebellar ataxia type 40
Inheritance: AD Classification: MODERATE, SUPPORTIVE, LIMITED Submitted by: Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Orphanet

CCDC88C links:

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ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 10 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;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CCDC88C	NM_001080414.4 link	c.114C>G	p.Tyr38*	stop_gained	Exon 2 of 30	ENST00000389857.11	NP_001073883.2	Q9P219-1B4DZB8
CCDC88C	XM_011536796.3 link	c.6C>G	p.Tyr2*	stop_gained	Exon 2 of 30		XP_011535098.1
CCDC88C	NR_189158.1 link	n.244C>G		non_coding_transcript_exon_variant	Exon 2 of 31
CCDC88C	NR_189159.1 link	n.244C>G		non_coding_transcript_exon_variant	Exon 2 of 31

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CCDC88C	ENST00000389857.11 link	c.114C>G	p.Tyr38*	stop_gained	Exon 2 of 30	5	NM_001080414.4	ENSP00000374507.6		Q9P219-1

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152056

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

Cov.:

GnomAD4 genome

AF:

0.00000658

AC:

AN:

152056

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74256

show subpopulations

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

African (AFR)

AF:

0.0000242

AC:

AN:

41384

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10584

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68008

Other (OTH)

AF:

0.00

AC:

AN:

2086

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

3042

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.51

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

Eigen

Uncertain

0.41

Eigen_PC

Benign

0.21

FATHMM_MKL

Benign

0.75

PhyloP100

0.46

Vest4

0.50

GERP RS

-0.035

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Mutation Taster

=3/197

disease causing (fs/PTC)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over