NM_004183.4:c.652C>G

Variant names:

• chr11-61957402-C-G
• rs281865238
• NM_004183.4:c.652C>G

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_004183.4(BEST1):​c.652C>G​(p.Arg218Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R218C) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BEST1 NM_004183.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 2.29
• Publications: 2 publications found

Genes affected

BEST1 (HGNC:12703): (bestrophin 1) This gene encodes a member of the bestrophin gene family. This small gene family is characterized by proteins with a highly conserved N-terminus with four to six transmembrane domains. Bestrophins may form chloride ion channels or may regulate voltage-gated L-type calcium-ion channels. Bestrophins are generally believed to form calcium-activated chloride-ion channels in epithelial cells but they have also been shown to be highly permeable to bicarbonate ion transport in retinal tissue. Mutations in this gene are responsible for juvenile-onset vitelliform macular dystrophy (VMD2), also known as Best macular dystrophy, in addition to adult-onset vitelliform macular dystrophy (AVMD) and other retinopathies. Alternative splicing results in multiple variants encoding distinct isoforms.[provided by RefSeq, Nov 2008]

BEST1 Gene-Disease associations (from GenCC):

• autosomal dominant vitreoretinochoroidopathy

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet, Labcorp Genetics (formerly Invitae), PanelApp Australia, G2P
• inherited retinal dystrophy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• retinitis pigmentosa

  Inheritance: AD, AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, G2P
• vitelliform macular dystrophy 2

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae), Orphanet
• autosomal recessive bestrophinopathy

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P
• retinitis pigmentosa 50

  Inheritance: AD Classification: STRONG, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
• adult-onset foveomacular vitelliform dystrophy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• MRCS syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• nanophthalmia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

LOC107984334 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 13 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_004183.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr11-61957402-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 99735.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 209 curated pathogenic missense variants (we use a threshold of 10). The gene has 23 curated benign missense variants. Gene score misZ: 0.61695 (below the threshold of 3.09). Trascript score misZ: 0.88358 (below the threshold of 3.09). GenCC associations: The gene is linked to vitelliform macular dystrophy 2, MRCS syndrome, autosomal recessive bestrophinopathy, autosomal dominant vitreoretinochoroidopathy, retinitis pigmentosa, retinitis pigmentosa 50, inherited retinal dystrophy, adult-onset foveomacular vitelliform dystrophy, nanophthalmia.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993
• PP5: Variant 11-61957402-C-G is Pathogenic according to our data. Variant chr11-61957402-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 1070185.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BEST1	NM_004183.4	c.652C>G	p.Arg218Gly	missense_variant	Exon 6 of 11	ENST00000378043.9	NP_004174.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BEST1	ENST00000378043.9	c.652C>G	p.Arg218Gly	missense_variant	Exon 6 of 11	1	NM_004183.4	ENSP00000367282.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Jul 29, 2020

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine with glycine at codon 218 of the BEST1 protein (p.Arg218Gly). The arginine residue is highly conserved and there is a moderate physicochemical difference between arginine and glycine. For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Arg218 amino acid residue in BEST1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 28687848, 29781975). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt BEST1 protein function. This variant has been observed in individual(s) with autosomal dominant Best vitelliform macular dystrophy (PMID: 23213274, 17646752). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (ExAC no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.53
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D;.;D
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.41
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.89	D;D;D
M_CAP	Pathogenic	0.59	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.9	H;.;.
PhyloP100		2.3
PrimateAI	Uncertain	0.49	T
PROVEAN	Pathogenic	-7.0	D;D;D
REVEL	Pathogenic	0.91
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	D;D;D
Vest4		0.92
MutPred		0.99		Loss of catalytic residue at R218 (P = 0.2575);.;.;
MVP		0.99
MPC		1.1
ClinPred		1.0	D
GERP RS		4.5
Varity_R		0.96
gMVP		0.94
Mutation Taster		=1/99	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs281865238; hg19: chr11-61724874;