rs28941469

Variant names:

• chr11-61957429-T-A
• rs28941469
• NM_004183.4:c.679T>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 topological_domain Extracellular (size 28) in uniprot entity BEST1_HUMAN there are 50 pathogenic changes around while only 1 benign (98%) 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 Lovd as [Likely_pathogenic].
• 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 rank	MANE	Protein	UniProt
BEST1	NM_004183.4	c.679T>A	p.Tyr227Asn	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.679T>A	p.Tyr227Asn	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:8 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:6 Other:1

Aug 01, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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) -

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Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

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Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

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Jul 03, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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). This variant is not present in population databases (gnomAD no frequency). 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. ClinVar contains an entry for this variant (Variation ID: 2731). 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. Experimental studies have shown that this missense change affects BEST1 function (PMID: 21878505, 23880862). 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. For these reasons, this variant has been classified as Pathogenic. -

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Genome Diagnostics Laboratory, Amsterdam University Medical Center

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

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Clinical Genetics, Academic Medical Center

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

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Retina International

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

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Vitelliform macular dystrophy 2 Pathogenic:1

Nov 01, 2005

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

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Retinal dystrophy Pathogenic:1

Dec 21, 2018

Blueprint Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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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
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;