rs28941469

Positions:

• chr11-61957429-T-A

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_004183.4(BEST1):​c.679T>A​(p.Tyr227Asn) variant causes a missense change involving the alteration of a 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. Y227C) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: BEST1 NM_004183.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:8 O:1
• Conservation: PhyloP100: 7.82

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]

LOC107984334 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PM1: In a hotspot region, there are 9 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 chr11-61957430-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2749.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992
• PP5: Variant 11-61957429-T-A is Pathogenic according to our data. Variant chr11-61957429-T-A is described in ClinVar as [Pathogenic]. Clinvar id is 2731.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-61957429-T-A is described in Lovd as [Pathogenic]. Variant chr11-61957429-T-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
BEST1	NM_004183.4	c.679T>A	p.Tyr227Asn	missense_variant	6/11	ENST00000378043.9
LOC107984334	XR_001748245.2	n.1265A>T		non_coding_transcript_exon_variant	2/2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
BEST1	ENST00000378043.9	c.679T>A	p.Tyr227Asn	missense_variant	6/11	1	NM_004183.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:8 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:6 Other:1

Pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jul 03, 2023	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. For these reasons, this variant has been classified as Pathogenic. This variant disrupts the p.Tyr227 amino acid residue in BEST1. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 9700209, 26418331, 28559085, 30582078). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Experimental studies have shown that this missense change affects BEST1 function (PMID: 21878505, 23880862). ClinVar contains an entry for this variant (Variation ID: 2731). This missense change has been observed in individuals with autosomal dominant Best disease (PMID: 9662395, 28559085). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces tyrosine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 227 of the BEST1 protein (p.Tyr227Asn). -
Pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -
not provided, no classification provided	literature only	Retina International	-	- -
Pathogenic, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, Amsterdam University Medical Center	-	- -
Pathogenic, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Aug 01, 2023	Published functional studies demonstrate a damaging effect due to altered cellular localization, a severe trafficking defect, and increased lysosomal degradation of the mislocalized protein (Milenkovic et al., 2011; Milenkovic el al., 2018); 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: 33154968, 17898294, 20381869, 23880862, 21878505, 29668979, 31201163, 14205432, 24560797, 28687848, 23633665, 27193166, 17591911, 17065513, 17460247, 19398034, 17477921, 21498618, 28559085, 9662395, 16286623, 19357557) -

Vitelliform macular dystrophy 2 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Nov 01, 2005

- -

Retinal dystrophy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Blueprint Genetics

Dec 21, 2018

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.72
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.98	D;.;D
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D;D
M_CAP	Pathogenic	0.83	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.0	D
MutationTaster	Benign	1.0	A;A;A;A;A;A;A
PrimateAI	Uncertain	0.65	T
PROVEAN	Pathogenic	-8.3	D;D;D
REVEL	Pathogenic	0.98
Sift	Uncertain	0.0020	D;D;D
Sift4G	Uncertain	0.0030	D;D;D
Polyphen		1.0	D;D;D
Vest4		0.97
MutPred		0.92		Loss of stability (P = 0.0125);.;.;
MVP		0.99
MPC		1.3
ClinPred		1.0	D
GERP RS		5.4
Varity_R		0.94
gMVP		0.97

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

LitVar

Other links and lift over

dbSNP: rs28941469; hg19: chr11-61724901;