rs121918290

Positions:

• chr11-61958146-G-A
• chr11-61958146-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2 PP3_Strong PP5_Moderate

The NM_001363593.2(BEST1):​c.-461G>A variant causes a 5 prime UTR premature start codon gain 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 Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 0)
• Consequence: BEST1 NM_001363593.2 5_prime_UTR_premature_start_codon_gain
• Scores: Splicing: ADA: 0.9679
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 9.74

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 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.975
• PP5: Variant 11-61958146-G-A is Pathogenic according to our data. Variant chr11-61958146-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2745.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr11-61958146-G-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BEST1	NM_004183.4	c.715G>A	p.Val239Met	missense_variant, splice_region_variant	7/11	ENST00000378043.9	NP_004174.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BEST1	ENST00000378043.9	c.715G>A	p.Val239Met	missense_variant, splice_region_variant	7/11	1	NM_004183.4	ENSP00000367282.4

Frequencies

GnomAD3 genomes Cov.: 0

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 0

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Microcornea, rod-cone dystrophy, cataract, and posterior staphyloma 2 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Oct 01, 2004

- -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Mar 15, 2022

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; An in vitro splicing assay suggested that V239M causes skipping of exons 6 and 7 and results in the production of bestrophin-1 isoforms containing in-frame deletions, possibly due to the disruption of an exonic splice enhancer. However, in vivo studies have not been performed to validate these findings (Yardley et al., 2004); This variant is associated with the following publications: (PMID: 15452077, 18611979, 24560797, 17065513, 26771239, 21473666, 30222024, 22454052, 24328569, 20362068, 19375515, 18391176, 30945270, 34746433, 27653836) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D;.;D
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Pathogenic	0.64	D
MetaRNN	Pathogenic	0.98	D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.8	H;.;.
PrimateAI	Uncertain	0.61	T
PROVEAN	Uncertain	-2.9	D;D;D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	D;D;D
Vest4		0.93
MutPred		0.86		Loss of catalytic residue at V239 (P = 0.0979);.;.;
MVP		0.99
MPC		1.0
ClinPred		1.0	D
GERP RS		5.0
Varity_R		0.90
gMVP		0.80

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.97
dbscSNV1_RF	Benign	0.65
SpliceAI score (max)		0.060		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: rs121918290; hg19: chr11-61725618;