11-61951823-C-G

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PS1_Moderate PM1 PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_004183.4(BEST1):c.17C>G(p.Thr6Arg) variant causes a missense change. 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 Likely pathogenic (★★). Another nucleotide change resulting in same amino acid change has been previously reported as Likely pathogenicin UniProt. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T6P) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BEST1 NM_004183.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2 O:1
• Conservation: PhyloP100: 5.98

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]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PS1: Transcript NM_004183.4 (BEST1) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in UniProt
• PM1: In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 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 chr11-61951822-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 858577.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.91
• PP5: Variant 11-61951823-C-G is Pathogenic according to our data. Variant chr11-61951823-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 99689.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-61951823-C-G is described in Lovd as [Pathogenic]. Variant chr11-61951823-C-G is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BEST1	NM_004183.4	c.17C>G	p.Thr6Arg	missense_variant	2/11	ENST00000378043.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BEST1	ENST00000378043.9	c.17C>G	p.Thr6Arg	missense_variant	2/11	1	NM_004183.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2 Other:1

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Mar 22, 2023	For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Thr6 amino acid residue in BEST1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 16769844). 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. ClinVar contains an entry for this variant (Variation ID: 99689). This missense change has been observed in individuals with autosomal dominant Best vitelliform macular dystrophy (PMID: 17477921, 17591911; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces threonine, which is neutral and polar, with arginine, which is basic and polar, at codon 6 of the BEST1 protein (p.Thr6Arg). -
not provided, no classification provided	literature only	Retina International	-	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Nov 10, 2023	Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 23633665, 17477921, 17591911, 17460247, 10798642, 32278767) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
Cadd	Uncertain	25
Dann	Uncertain	0.99
DEOGEN2	Uncertain	0.77	D
Eigen	Pathogenic	0.75
Eigen_PC	Pathogenic	0.66
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D
M_CAP	Pathogenic	0.36	D
MetaRNN	Pathogenic	0.91	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.2	M
MutationTaster	Benign	1.0	D;D;D;D;D;D
PROVEAN	Uncertain	-3.9	D
REVEL	Pathogenic	0.83
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0050	D
Polyphen		0.94	P
Vest4		0.44
MutPred		0.86		Gain of MoRF binding (P = 0.0245);
MVP		1.0
ClinPred		0.98	D
GERP RS		5.6
Varity_R		0.80

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

Other links and lift over

dbSNP: rs281865204; hg19: chr11-61719295;