rs61748538

Variant names:

• chr1-94098904-G-A
• rs61748538
• NM_000350.3:c.658C>T

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1 PP2 PP5_Very_Strong

The NM_000350.3(ABCA4):​c.658C>T​(p.Arg220Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000868 in 1,613,824 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. R220R) has been classified as Likely benign. The gene ABCA4 is included in the ClinGen Criteria Specification Registry.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: ABCA4 NM_000350.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7 O:1
• Conservation: PhyloP100: 0.376
• Publications: 11 publications found

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
• age related macular degeneration 2

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Specifications for ABCA4 are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Our verdict: Pathogenic. The variant received 11 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 13 uncertain in NM_000350.3
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 578 curated pathogenic missense variants (we use a threshold of 10). The gene has 28 curated benign missense variants. Gene score misZ: -0.65813 (below the threshold of 3.09). Trascript score misZ: 1.3628 (below the threshold of 3.09). GenCC associations: The gene is linked to severe early-childhood-onset retinal dystrophy, retinitis pigmentosa, age related macular degeneration 2, retinitis pigmentosa 19, cone-rod dystrophy 3, ABCA4-related retinopathy, Stargardt disease, cone-rod dystrophy.
• PP5: Variant 1-94098904-G-A is Pathogenic according to our data. Variant chr1-94098904-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 99471.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000350.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ABCA4	NM_000350.3	MANE Select	c.658C>T	p.Arg220Cys	missense	Exon 6 of 50	NP_000341.2	P78363
	ABCA4	NM_001425324.1		c.658C>T	p.Arg220Cys	missense	Exon 6 of 49	NP_001412253.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ABCA4	ENST00000370225.4	TSL:1 MANE Select	c.658C>T	p.Arg220Cys	missense	Exon 6 of 50	ENSP00000359245.3	P78363
	ABCA4	ENST00000649773.1		c.658C>T	p.Arg220Cys	missense	Exon 6 of 19	ENSP00000496882.1	A0A3B3IRV8

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152208 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000797 AC: 2 AN: 251044 AF XY: 0.0000147

Gnomad AFR exome AF: 0.0000615

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000821 AC: 12 AN: 1461616 Hom.: 0 Cov.: 31 AF XY: 0.00000963 AC XY: 7 AN XY: 727084

African (AFR) AF: 0.0000299 AC: 1 AN: 33480

American (AMR) AF: 0.0000224 AC: 1 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53150

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000809 AC: 9 AN: 1112008

Other (OTH) AF: 0.0000166 AC: 1 AN: 60394

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152208 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74364

African (AFR) AF: 0.0000241 AC: 1 AN: 41460

American (AMR) AF: 0.00 AC: 0 AN: 15276

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5196

South Asian (SAS) AF: 0.00 AC: 0 AN: 4824

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10624

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68040

Other (OTH) AF: 0.00 AC: 0 AN: 2088

Alfa AF: 0.0000214 Hom.: 0

Bravo AF: 0.0000151

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
2	-	-	not provided (3)
2	-	-	Retinal dystrophy (2)
2	-	-	Severe early-childhood-onset retinal dystrophy;C1858806:Cone-rod dystrophy 3;C1866422:Retinitis pigmentosa 19;C3495438:Age related macular degeneration 2 (2)
1	-	-	Severe early-childhood-onset retinal dystrophy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Uncertain	0.15	D
BayesDel_noAF	Pathogenic	0.15
CADD	Benign	20
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.57	D
Eigen	Benign	-0.25
Eigen_PC	Benign	-0.42
FATHMM_MKL	Benign	0.086	N
LIST_S2	Benign	0.85	T
M_CAP	Uncertain	0.14	D
MetaRNN	Uncertain	0.71	D
MetaSVM	Benign	-0.38	T
MutationAssessor	Uncertain	2.1	M
PhyloP100		0.38
PrimateAI	Benign	0.23	T
PROVEAN	Benign	-1.6	N
REVEL	Uncertain	0.57
Sift	Benign	0.14	T
Sift4G	Uncertain	0.060	T
Polyphen		0.95	P
Vest4		0.59
MutPred		0.80		Loss of MoRF binding (P = 0.0299)
MVP		0.91
MPC		0.37
ClinPred		0.47	T
GERP RS		1.4
Varity_R		0.090
gMVP		0.61
Mutation Taster		=86/14	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs61748538; hg19: chr1-94564460; COSMIC: COSV64671902;