NM_000350.3:c.768G>T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PP3_StrongPP5_Very_Strong

The NM_000350.3(ABCA4):c.768G>T(p.Val256Val) variant causes a splice region, synonymous change. The variant allele was found at a frequency of 0.0000793 in 1,614,042 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.000059 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000081 ( 0 hom. )

Consequence

ABCA4
NM_000350.3 splice_region, synonymous

Scores

Splicing: ADA: 1.000

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:20O:1

Conservation

PhyloP100: 5.74

Publications

57 publications found

Variant links:

Genes affected

ABCA4 (HGNC:34): (ATP binding cassette subfamily A member 4) The membrane-associated protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intracellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the ABC1 subfamily. Members of the ABC1 subfamily comprise the only major ABC subfamily found exclusively in multicellular eukaryotes. This protein is a retina-specific ABC transporter with N-retinylidene-PE as a substrate. It is expressed exclusively in retina photoreceptor cells, and the gene product mediates transport of an essental molecule, all-trans-retinal aldehyde (atRAL), across the photoreceptor cell membrane. Mutations in this gene are found in patients diagnosed with Stargardt disease, a form of juvenile-onset macular degeneration. Mutations in this gene are also associated with retinitis pigmentosa-19, cone-rod dystrophy type 3, early-onset severe retinal dystrophy, fundus flavimaculatus, and macular degeneration age-related 2. [provided by RefSeq, Sep 2019]

ABCA4 Gene-Disease associations (from GenCC):

ABCA4-related retinopathy
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
cone-rod dystrophy 3
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
severe early-childhood-onset retinal dystrophy
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae), Ambry Genetics
retinitis pigmentosa 19
Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
cone-rod dystrophy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
retinitis pigmentosa
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Stargardt disease
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ABCA4 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 12 ACMG points.

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

PP5

Variant 1-94098794-C-A is Pathogenic according to our data. Variant chr1-94098794-C-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 99505.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ABCA4	NM_000350.3 link	c.768G>T	p.Val256Val	splice_region_variant, synonymous_variant	Exon 6 of 50	ENST00000370225.4	NP_000341.2	P78363Q6AI28
ABCA4	NM_001425324.1 link	c.768G>T	p.Val256Val	splice_region_variant, synonymous_variant	Exon 6 of 49		NP_001412253.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ABCA4	ENST00000370225.4 link	c.768G>T	p.Val256Val	splice_region_variant, synonymous_variant	Exon 6 of 50	1	NM_000350.3	ENSP00000359245.3		P78363
ABCA4	ENST00000649773.1 link	c.768G>T	p.Val256Val	splice_region_variant, synonymous_variant	Exon 6 of 19			ENSP00000496882.1		A0A3B3IRV8

Frequencies

GnomAD3 genomes

AF:

0.0000591

AC:

AN:

152216

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000132

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000875

AC:

AN:

251394

AF XY:

0.0000589

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000193

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000814

AC:

119

AN:

1461826

Hom.:

Cov.:

AF XY:

0.0000756

AC XY:

AN XY:

727212

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53370

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.000103

AC:

115

AN:

1112000

Other (OTH)

AF:

0.0000662

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.478

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000591

AC:

AN:

152216

Hom.:

Cov.:

AF XY:

0.0000672

AC XY:

AN XY:

74366

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41448

American (AMR)

AF:

0.00

AC:

AN:

15286

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000132

AC:

AN:

68038

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.469

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000725

Hom.:

Bravo

AF:

0.0000491

EpiCase

AF:

0.000164

EpiControl

AF:

0.000178

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:20Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:8Other:1

Jun 14, 2022

Revvity Omics, Revvity

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

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

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Retina International

Significance:not provided

Review Status:no classification provided

Collection Method:literature only

- -

Mar 01, 2024

CeGaT Center for Human Genetics Tuebingen

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

ABCA4: PM3:Very Strong, PM2, PP3, PS3:Supporting -

Dec 29, 2022

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Published functional studies demonstrate a damaging effect, specifically, the c.768 G>T variant results in low or absent mRNA expression (Maugeri et al., 1999); In silico analysis is inconclusive as to whether the variant alters gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown.; This variant is associated with the following publications: (PMID: 26261413, 15161829, 23695285, 28118664, 31429209, 32531858, 31522899, 33706644, 22968130, 19074458, 24453473, 22264887, 10090887, 23891399, 28771251, 29310964, 31618761, 30903310, 32581362, 32810830, 33851411, 31573552, 31589614, 29555955, 30718709, 29162642, 20647261, 35119454, 35112029, 22328824, 29925512) -

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

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Sep 15, 2021

Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 16, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change affects codon 256 of the ABCA4 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the ABCA4 protein. RNA analysis indicates that this variant induces altered splicing and may result in an absent or altered protein product. This variant is present in population databases (rs62645944, gnomAD 0.02%). This variant has been observed in individual(s) with Stargardt disease (PMID: 10090887, 11726554, 15161829, 23695285). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 99505). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant results in activation of a cryptic splice site, and produces a non-functional protein and/or introduces a premature termination codon (PMID: 10090887, 29162642). For these reasons, this variant has been classified as Pathogenic. -

Dec 09, 2016

Eurofins Ntd Llc (ga)

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Severe early-childhood-onset retinal dystrophy

Pathogenic:3

Jan 01, 2016

Institute of Human Genetics, Univ. Regensburg, Univ. Regensburg

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 01, 2015

NIHR Bioresource Rare Diseases, University of Cambridge

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:research

- -

Jan 30, 2021

Institute of Medical Molecular Genetics, University of Zurich

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Retinal dystrophy

Pathogenic:2

Jan 01, 2023

Institute of Human Genetics, Univ. Regensburg, Univ. Regensburg

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Aug 06, 2019

Blueprint Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

ABCA4-related disorder

Pathogenic:1

Aug 11, 2023

PreventionGenetics, part of Exact Sciences

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The ABCA4 c.768G>T variant is not predicted to result in an amino acid change (p.=). However, this variant is predicted to impact splicing (Alamut Visual v.2.11). This variant has been reported many times in the compound heterozygous state to be causative for severe autosomal recessive retinal disorders (see for examples Maugeri et al. 1999. PubMed ID: 10090887; Table S2 in Schulz et al. 2017. PubMed ID: 28118664; Table S1 in Birtel et al. 2018. PubMed ID: 29555955; Table S4 in Jespersgaard et al. 2019. PubMed ID: 30718709). Functional analysis using RT-PCR confirmed that this variant affects splicing and results in an abnormal splicing product (Sangermano et al. 2018. PubMed ID: 29162642). This variant is reported in 0.019% of alleles in individuals of European (Non-Finnish) descent in gnomAD (http://gnomad.broadinstitute.org/variant/1-94564350-C-A). Given the evidence, we interpret c.768G>T (p.=) as pathogenic. -

Macular dystrophy

Pathogenic:1

Apr 01, 2018

Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:research

- -

Retinitis pigmentosa 19

Pathogenic:1

Sep 01, 2016

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

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Cone-rod dystrophy 3

Pathogenic:1

Mar 28, 2023

Institute of Human Genetics, University of Leipzig Medical Center

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Criteria applied: PS3,PM3_STR,PM2_SUP,PP3 -

Severe early-childhood-onset retinal dystrophy;C1858806:Cone-rod dystrophy 3;C1866422:Retinitis pigmentosa 19;C3495438:Age related macular degeneration 2

Pathogenic:1

May 09, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Retinitis pigmentosa

Pathogenic:1

Apr 01, 2018

Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet

Significance:Likely pathogenic

Review Status:no assertion criteria provided

Collection Method:research

- -

Stargardt disease

Pathogenic:1

Mar 30, 2023

Molecular Genetics, Royal Melbourne Hospital

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change is a synonymous (silent) variant in exon 6 of ABCA4 that is predicted to impact splicing (SpliceAI, MaxEntScan, NNSplice). This prediction is confirmed by RT-PCR analysis of patient RNA and midi-gene generated from bacterial artificial chromosome. The assays demonstrated that the variant impacts splicing by cryptic donor site activiation in intron 6 producing a 35 bp frame-shift insertion (p.Leu257Valfs*17; PMID: 10090887, 29162642). The highest population minor allele frequency in gnomAD v2.1 is 0.02% (24/129,168 alleles) in the European (non-Finnish) population, which is consistent with recessive disease. This variant has been detected homozygous and compound heterozygous with a second pathogenic variant in multiple invidivuals with various retinal disorders, including retinitis pimentosa, Stargardt disease, and unscpeficied macular dystrophy (PMID: 10090887, 11726554, 28118664, 30718709, 33546218). Based on the classification scheme RMH Modified ACMG Guidelines v1.5.1, this variant is classified as PATHOGENIC. Following criteria are met: PS3, PM3_VeryStrong, PM2_Supporting, PP3. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.24

CADD

Benign

(source)

DANN

Benign

0.91

PhyloP100

5.7

Mutation Taster

=0/100

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.95

SpliceAI score (max)

0.71

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.71

Position offset: -35

DS_DL_spliceai

0.42

Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over