Genetic Variant NM_000651.6:c.6830C>T (chr1-207616743-C-T) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_000651.6(CR1):c.6830C>T(p.Pro2277Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,712 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/20 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P2277R) has been classified as Benign.

Frequency

Genomes: not found (cov: 30)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

CR1
NM_000651.6 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -0.827

Publications

0 publications found

Variant links:

Genes affected

CR1 (HGNC:2334): (complement C3b/C4b receptor 1 (Knops blood group)) This gene is a member of the receptors of complement activation (RCA) family and is located in the 'cluster RCA' region of chromosome 1. The genome is polymorphic at this locus with allele-specific splice variants encoding different isoforms, based on the presence/absence of long homologous repeats (LHRs). The gene encodes a monomeric single-pass type I membrane glycoprotein found on erythrocytes, leukocytes, glomerular podocytes, and splenic follicular dendritic cells. The Knops blood group system is a system of antigens located on this protein. The protein mediates cellular binding to particles and immune complexes that have activated complement. Decreases in expression of this protein and/or mutations in this gene have been associated with gallbladder carcinomas, mesangiocapillary glomerulonephritis, systemic lupus erythematosus, sarcoidosis and Alzheimer's disease. Mutations in this gene have also been associated with a reduction in Plasmodium falciparum rosetting, conferring protection against severe malaria. [provided by RefSeq, May 2020]

CR1 links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.058918744).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CR1	NM_000651.6 link	c.6830C>T	p.Pro2277Leu	missense_variant	Exon 41 of 47	ENST00000367049.9	NP_000642.3	P17927E9PDY4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CR1	ENST00000367049.9 link	c.6830C>T	p.Pro2277Leu	missense_variant	Exon 41 of 47	5	NM_000651.6	ENSP00000356016.4		E9PDY4

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461712

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727138

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53402

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111870

Other (OTH)

AF:

0.00

AC:

AN:

60374

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), 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

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.074

BayesDel_addAF

Benign

-0.22

BayesDel_noAF

Benign

-0.56

CADD

Benign

0.98

(source)

DANN

Benign

0.42

Eigen

Benign

-1.9

Eigen_PC

Benign

-2.0

FATHMM_MKL

Benign

0.0073

LIST_S2

Benign

0.28

.;.;.;T;T

M_CAP

Benign

0.0035

MetaRNN

Benign

0.059

T;T;T;T;T

MetaSVM

Benign

-0.98

PhyloP100

-0.83

PrimateAI

Benign

0.23

PROVEAN

Benign

-1.5

N;N;N;N;N

REVEL

Benign

0.067

Sift

Benign

0.33

T;T;T;T;T

Sift4G

Benign

0.086

T;T;T;T;T

Polyphen

0.0

.;.;.;.;B

Vest4

0.10

MutPred

0.56

.;.;.;.;Loss of disorder (P = 0.021);

MVP

0.23

MPC

0.11

ClinPred

0.040

GERP RS

-5.6

gMVP

0.23

Mutation Taster

=100/0

polymorphism

(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