1-94024978-G-C

Variant names:

• chr1-94024978-G-C
• rs62642575
• NM_000350.3:c.4610C>G

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate

The NM_000350.3(ABCA4):​c.4610C>G​(p.Thr1537Arg) 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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T1537M) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: ABCA4 NM_000350.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.96
• Publications: 0 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

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_000350.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-94024978-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 99306.
• 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 cone-rod dystrophy 3, retinitis pigmentosa 19, ABCA4-related retinopathy, severe early-childhood-onset retinal dystrophy, cone-rod dystrophy, Stargardt disease, retinitis pigmentosa.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.923

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ABCA4	NM_000350.3	c.4610C>G	p.Thr1537Arg	missense_variant	Exon 31 of 50	ENST00000370225.4	NP_000341.2
ABCA4	NM_001425324.1	c.4388C>G	p.Thr1463Arg	missense_variant	Exon 30 of 49		NP_001412253.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ABCA4	ENST00000370225.4	c.4610C>G	p.Thr1537Arg	missense_variant	Exon 31 of 50	1	NM_000350.3	ENSP00000359245.3
ABCA4	ENST00000460514.1	n.104C>G		non_coding_transcript_exon_variant	Exon 2 of 7	5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.40
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Benign	0.37	T;D
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.78	D
MetaRNN	Pathogenic	0.92	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.0	.;M
PhyloP100		8.0
PrimateAI	Uncertain	0.72	T
PROVEAN	Pathogenic	-5.3	.;D
REVEL	Pathogenic	0.92
Sift	Pathogenic	0.0	.;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	.;D
Vest4		0.96
MutPred		0.67		.;Loss of sheet (P = 0.0054);
MVP		1.0
MPC		0.50
ClinPred		1.0	D
GERP RS		5.1
Varity_R		0.89
gMVP		0.95
Mutation Taster		=2/98	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.32		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.32		Position offset: 0

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

Other links and lift over

dbSNP: rs62642575; hg19: chr1-94490534;