chr11-2885300-C-CCCAGCTGGAA

Position:

• chr11-2885300-C-CCCAGCTGGAA

Variant summary

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

The NM_001122630.2(CDKN1C):​c.156_157insTTCCAGCTGG​(p.Asp53PhefsTer64) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. Y52Y) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: CDKN1C NM_001122630.2 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 1.91

Genes affected

CDKN1C (HGNC:1786): (cyclin dependent kinase inhibitor 1C) This gene is imprinted, with preferential expression of the maternal allele. The encoded protein is a tight-binding, strong inhibitor of several G1 cyclin/Cdk complexes and a negative regulator of cell proliferation. Mutations in this gene are implicated in sporadic cancers and Beckwith-Wiedemann syndorome, suggesting that this gene is a tumor suppressor candidate. Three transcript variants encoding two different isoforms have been found for this gene. [provided by RefSeq, Oct 2010]

ACMG classification

Verdict is Pathogenic. Variant got 12 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
• PP5: Variant 11-2885300-C-CCCAGCTGGAA is Pathogenic according to our data. Variant chr11-2885300-C-CCCAGCTGGAA is described in ClinVar as [Pathogenic]. Clinvar id is 524696.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CDKN1C	NM_001122630.2	c.156_157insTTCCAGCTGG	p.Asp53PhefsTer64	frameshift_variant	2/4	ENST00000440480.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CDKN1C	ENST00000440480.8	c.156_157insTTCCAGCTGG	p.Asp53PhefsTer64	frameshift_variant	2/4	1	NM_001122630.2	A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Beckwith-Wiedemann syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 18, 2021

For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has not been reported in the literature in individuals with CDKN1C-related conditions. ClinVar contains an entry for this variant (Variation ID: 524696). This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Asp64Phefs*64) in the CDKN1C gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in CDKN1C are known to be pathogenic (PMID: 20503313). -

Computational scores

Source: dbNSFP v4.3

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs1554938197; hg19: chr11-2906530;