chr11-61951822-A-G

Position:

• chr11-61951822-A-G

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.16A>G​(p.Thr6Ala) 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T6R) has been classified as Likely 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
• Conservation: PhyloP100: 3.09

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.

• PM1: In a helix (size 3) in uniprot entity BEST1_HUMAN there are 15 pathogenic changes around while only 0 benign (100%) 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 chrnull-null-null-null is described in UniProt as null.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.959
• PP5: Variant 11-61951822-A-G is Pathogenic according to our data. 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. Variant chr11-61951822-A-G is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BEST1	NM_004183.4	c.16A>G	p.Thr6Ala	missense_variant	2/11	ENST00000378043.9	NP_004174.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BEST1	ENST00000378043.9	c.16A>G	p.Thr6Ala	missense_variant	2/11	1	NM_004183.4	ENSP00000367282	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 27, 2023

This sequence change replaces threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 6 of the BEST1 protein (p.Thr6Ala). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with autosomal dominant Best macular dystrophy (PMID: 16769844). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 858577). 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 with a positive predictive value of 95%. This variant disrupts the p.Thr6 amino acid residue in BEST1. Other variant(s) that disrupt this residue have been observed in individuals with BEST1-related conditions (PMID: 9662395, 28687848), which suggests that this may be a clinically significant amino acid residue. For these reasons, this variant has been classified as Pathogenic. -

Retinal dystrophy Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Blueprint Genetics

Aug 16, 2019

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.31
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.18
CADD	Benign	19
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.53	D
Eigen	Benign	-0.046
Eigen_PC	Benign	-0.15
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.91	D
M_CAP	Pathogenic	0.31	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Pathogenic	0.89	D
MutationAssessor	Uncertain	2.2	M
MutationTaster	Benign	0.99	D;D;D;D;D;D
PROVEAN	Uncertain	-2.5	D
REVEL	Pathogenic	0.75
Sift	Uncertain	0.024	D
Sift4G	Uncertain	0.019	D
Polyphen		0.49	P
Vest4		0.70
MutPred		0.86		Loss of disorder (P = 0.1613);
MVP		0.97
ClinPred		0.91	D
GERP RS		-1.6
Varity_R		0.24

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: rs28940275; hg19: chr11-61719294;