chr16-88805870-G-A

Position:

• chr16-88805870-G-A

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_030928.4(CDT1):​c.832+1G>A variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: CDT1 NM_030928.4 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 9.06

Genes affected

CDT1 (HGNC:24576): (chromatin licensing and DNA replication factor 1) The protein encoded by this gene is involved in the formation of the pre-replication complex that is necessary for DNA replication. The encoded protein can bind geminin, which prevents replication and may function to prevent this protein from initiating replication at inappropriate origins. Phosphorylation of this protein by cyclin A-dependent kinases results in degradation of the protein. [provided by RefSeq, Mar 2011]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 3.5, offset of 11, new splice context is: tggGTgcgg. 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
• PP5: Variant 16-88805870-G-A is Pathogenic according to our data. Variant chr16-88805870-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 128664.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CDT1	NM_030928.4	c.832+1G>A		splice_donor_variant		ENST00000301019.9	NP_112190.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CDT1	ENST00000301019.9	c.832+1G>A		splice_donor_variant		1	NM_030928.4	ENSP00000301019	P1
CDT1	ENST00000569140.1	c.102+1G>A		splice_donor_variant		3		ENSP00000456926
CDT1	ENST00000562747.1	n.538+1G>A		splice_donor_variant, non_coding_transcript_variant		2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1460512 Hom.: 0 Cov.: 39 AF XY: 0.00 AC XY: 0 AN XY: 726508

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 30, 2019

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Donor and acceptor splice site variants typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in CDT1 are known to be pathogenic (PMID: 21358632, 22333897). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus 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 CDT1-related disease. ClinVar contains an entry for this variant (Variation ID: 128664). This variant is not present in population databases (ExAC no frequency). This sequence change affects a donor splice site in intron 5 of the CDT1 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. -

Meier-Gorlin syndrome 4 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Genetic Services Laboratory, University of Chicago

Mar 28, 2013

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	-0.080
CADD	Pathogenic	36
DANN	Uncertain	0.99
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Pathogenic	0.99	D
MutationTaster	Benign	1.0	D
GERP RS		3.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.79
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.92		Position offset: 35
DS_DL_spliceai		1.0		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs587780305; hg19: chr16-88872278;