1-207761248-G-A

Position:

• chr1-207761248-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PVS1_Strong PM2 PP5

The NM_172351.3(CD46):​c.476-1G>A variant causes a splice acceptor change. 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 Pathogenic (no stars).

• Frequency: Genomes: not found (cov: 33)
• Consequence: CD46 NM_172351.3 splice_acceptor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 4.62

Genes affected

CD46 (HGNC:6953): (CD46 molecule) The protein encoded by this gene is a type I membrane protein and is a regulatory part of the complement system. The encoded protein has cofactor activity for inactivation of complement components C3b and C4b by serum factor I, which protects the host cell from damage by complement. In addition, the encoded protein can act as a receptor for the Edmonston strain of measles virus, human herpesvirus-6, and type IV pili of pathogenic Neisseria. Finally, the protein encoded by this gene may be involved in the fusion of the spermatozoa with the oocyte during fertilization. Mutations at this locus have been associated with susceptibility to hemolytic uremic syndrome. Alternatively spliced transcript variants encoding different isoforms have been described. [provided by RefSeq, Jun 2010]

MIR29B2CHG (HGNC:32018): (MIR29B2 and MIR29C host gene)

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.17372134 fraction of the gene. Cryptic splice site detected, with MaxEntScore 9.1, offset of 2, new splice context is: tttttcttcatttttaaaAGgtt. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-207761248-G-A is Pathogenic according to our data. Variant chr1-207761248-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 988245.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CD46	NM_172351.3	c.476-1G>A		splice_acceptor_variant		ENST00000367042.6	NP_758861.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CD46	ENST00000367042.6	c.476-1G>A		splice_acceptor_variant		1	NM_172351.3	ENSP00000356009	A2
MIR29B2CHG	ENST00000710901.1	n.2403C>T		non_coding_transcript_exon_variant	6/6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 28

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Atypical hemolytic-uremic syndrome Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Sydney Genome Diagnostics, Children's Hospital Westmead

Aug 28, 2018

This patient is heterozygous for the c.476-1G>A variant in intron 4 of the CD46 gene. To our knowledge, this variant has not been previously reported and no frequency data is available. In silico analysis (Alamut Visual v2.7.2) predicts that this variant abolishes the consensus splice acceptor site at c.476, resulting in the skipping of exon 5, and is likely to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Benign	-0.14
CADD	Uncertain	24
DANN	Uncertain	0.99
Eigen	Pathogenic	0.88
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Uncertain	0.94	D
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D;D;D
GERP RS		4.6

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.90
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.42		Position offset: 3
DS_AL_spliceai		0.99		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: rs1441390681; hg19: chr1-207934593;