Genetic Variant CNGA1:c.288-26G>A (chr4-47943438-C-T) – ACMG Classification: Likely_benign (-4 pts)

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_Strong

The NM_001379270.1(CNGA1):c.288-26G>A variant causes a intron change involving the alteration of a non-conserved nucleotide. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. There are indicators that this mutation may affect the branch point..

Frequency

Genomes: 𝑓 0.0 ( 0 hom., cov: 29)

Exomes 𝑓: 8.5e-7 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

CNGA1
NM_001379270.1 intron

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 0.157

Publications

9 publications found

Variant links:

Genes affected

CNGA1 (HGNC:2148): (cyclic nucleotide gated channel subunit alpha 1) The protein encoded by this gene is involved in phototransduction. Along with another protein, the encoded protein forms a cGMP-gated cation channel in the plasma membrane, allowing depolarization of rod photoreceptors. This represents the last step in the phototransduction pathway. Defects in this gene are a cause of retinitis pigmentosa autosomal recessive (ARRP) disease. Multiple transcript variants have been found for this gene. [provided by RefSeq, Oct 2019]

CNGA1 links:

NIPAL1 (HGNC:27194): (NIPA like domain containing 1) Predicted to enable magnesium ion transmembrane transporter activity. Predicted to be involved in magnesium ion transport. Predicted to be integral component of membrane. Predicted to be active in membrane. [provided by Alliance of Genome Resources, Apr 2022]

NIPAL1 links:

LOC101927157 (HGNC:):

LOC101927157 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -4 ACMG points.

BP4

This position, referring to a specific DNA site, is a probable branch point but is likely benign (scored 3 / 10, using the threshold of <=3). The score ranges from 0 to 10, with values ≤3 considered benign and >5 classified as pathogenic. Computational evidence support a benign effect (BayesDel_noAF=-0.74).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CNGA1	NM_001379270.1 link	c.288-26G>A		intron_variant	Intron 6 of 10	ENST00000514170.7	NP_001366199.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CNGA1	ENST00000514170.7 link	c.288-26G>A		intron_variant	Intron 6 of 10	5	NM_001379270.1	ENSP00000426862.3

Frequencies

GnomAD3 genomes

AF:

0.00

AC:

AN:

151732

Hom.:

Cov.:

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

8.49e-7

AC:

AN:

1177474

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

588692

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

25156

American (AMR)

AF:

0.00

AC:

AN:

22282

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

22056

East Asian (EAS)

AF:

0.00

AC:

AN:

34180

South Asian (SAS)

AF:

0.0000150

AC:

AN:

66458

European-Finnish (FIN)

AF:

0.00

AC:

AN:

47942

Middle Eastern (MID)

AF:

0.00

AC:

AN:

3780

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

905724

Other (OTH)

AF:

0.00

AC:

AN:

49896

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.225

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

151732

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74072

African (AFR)

AF:

0.00

AC:

AN:

41284

American (AMR)

AF:

0.00

AC:

AN:

15236

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5192

South Asian (SAS)

AF:

0.00

AC:

AN:

4810

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10482

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67958

Other (OTH)

AF:

0.00

AC:

AN:

2076

Alfa

AF:

0.00

Hom.:

8486

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.74

CADD

Benign

8.6

(source)

DANN

Benign

0.35

PhyloP100

0.16

BranchPoint Hunter

3.0

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over