Genetic Variant NM_001891.4:c.165C>G (chr4-69957784-G-C) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_001891.4(CSN2):c.165C>G(p.Ile55Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000192 in 1,612,918 control chromosomes in the GnomAD database, with no homozygous occurrence. 13/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000020 ( 0 hom. )

Consequence

CSN2
NM_001891.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.287

Variant links:

Genes affected

CSN2 (HGNC:2447): (casein beta) This gene is a member of the beta casein family. There are two types of casein protein, beta (encoded by this gene) and kappa, both of which are secreted in human milk. Beta casein is the principal protein in human milk and the primary source of essential amino acids for a suckling infant. Beta and kappa casein proteins acting together form spherical micelles which bind within them important dietary minerals, such as calcium and phosphorous. In addition, the C-terminal 14 aa of the protein has antimicrobial activity, especially in preterm milk, displaying antibacterial activity against S. aureus and Y. enterocolitica. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2020]

CSN2 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CSN2	NM_001891.4 link	c.165C>G	p.Ile55Met	missense_variant	Exon 6 of 8	ENST00000353151.4	NP_001882.1	P05814W5RWE1
CSN2	NM_001302770.2 link	c.162C>G	p.Ile54Met	missense_variant	Exon 6 of 8		NP_001289699.1	P05814
CSN2	NM_001385731.1 link	c.120C>G	p.Ile40Met	missense_variant	Exon 5 of 7		NP_001372660.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CSN2	ENST00000353151.4 link	c.165C>G	p.Ile55Met	missense_variant	Exon 6 of 8	1	NM_001891.4	ENSP00000341030.3		P05814

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

152070

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000561

AC:

AN:

249568

Hom.:

AF XY:

0.0000741

AC XY:

AN XY:

134910

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000232

Gnomad ASJ exome

AF:

0.0000997

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000267

Gnomad OTH exome

AF:

0.000329

GnomAD4 exome

AF:

0.0000199

AC:

AN:

1460848

Hom.:

Cov.:

AF XY:

0.0000248

AC XY:

AN XY:

726542

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.000269

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000720

Gnomad4 OTH exome

AF:

0.0000994

GnomAD4 genome

AF:

0.0000132

AC:

AN:

152070

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74264

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000434

Hom.:

Bravo

AF:

0.0000264

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Jun 27, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.165C>G (p.I55M) alteration is located in exon 5 (coding exon 5) of the CSN2 gene. This alteration results from a C to G substitution at nucleotide position 165, causing the isoleucine (I) at amino acid position 55 to be replaced by a methionine (M). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Benign

-0.28

BayesDel_noAF

Benign

-0.36

CADD

Benign

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.57

Eigen

Benign

-0.39

Eigen_PC

Benign

-0.59

FATHMM_MKL

Benign

0.17

M_CAP

Benign

0.0049

MetaRNN

Uncertain

0.48

MetaSVM

Benign

-0.97

MutationAssessor

Benign

1.9

PrimateAI

Benign

0.44

PROVEAN

Benign

-1.6

REVEL

Benign

0.10

Sift

Uncertain

0.0020

Sift4G

Uncertain

0.043

Polyphen

0.96

Vest4

0.39

MutPred

0.48

Gain of glycosylation at Y56 (P = 0.0158);

MVP

0.24

MPC

0.0032

ClinPred

0.091

GERP RS

1.7

Varity_R

0.10

gMVP

0.16

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over