Genetic Variant NM_000883.4:c.1575G>T (chr7-128394575-C-A) – ACMG Classification: Likely_benign (-3 pts)

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 1P and 4B. PP3BS2

The NM_000883.4(IMPDH1):c.1575G>T(p.Ala525Ala) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,613,436 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. A525A) has been classified as Benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 31)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

IMPDH1
NM_000883.4 synonymous

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -2.88

Publications

30 publications found

Variant links:

Genes affected

IMPDH1 (HGNC:6052): (inosine monophosphate dehydrogenase 1) The protein encoded by this gene acts as a homotetramer to regulate cell growth. The encoded protein is an enzyme that catalyzes the synthesis of xanthine monophosphate (XMP) from inosine-5'-monophosphate (IMP). This is the rate-limiting step in the de novo synthesis of guanine nucleotides. Defects in this gene are a cause of retinitis pigmentosa type 10 (RP10). Several transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Dec 2008]

IMPDH1 Gene-Disease associations (from GenCC):

inherited retinal dystrophy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
Leber congenital amaurosis 11
Inheritance: AD Classification: DEFINITIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), G2P
retinitis pigmentosa 10
Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae)
Leber congenital amaurosis
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
retinitis pigmentosa
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

IMPDH1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -3 ACMG points.

PP3

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

BS2

High AC in GnomAdExome4 at 5 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IMPDH1	NM_000883.4 link	c.1575G>T	p.Ala525Ala	synonymous_variant	Exon 15 of 17	ENST00000338791.11	NP_000874.2	P20839-6B3KRZ3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IMPDH1	ENST00000338791.11 link	c.1575G>T	p.Ala525Ala	synonymous_variant	Exon 15 of 17	2	NM_000883.4	ENSP00000345096.6		P20839-6

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

151874

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000342

AC:

AN:

1461562

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727084

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44720

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:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53180

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5736

European-Non Finnish (NFE)

AF:

0.00000450

AC:

AN:

1111970

Other (OTH)

AF:

0.00

AC:

AN:

60388

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000658

AC:

AN:

151874

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74146

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

41330

American (AMR)

AF:

0.00

AC:

AN:

15270

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5150

South Asian (SAS)

AF:

0.00

AC:

AN:

4816

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10574

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

67948

Other (OTH)

AF:

0.00

AC:

AN:

2090

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

3739

Bravo

AF:

0.00000756

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.68

CADD

Benign

7.1

(source)

DANN

Benign

0.48

PhyloP100

-2.9

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.54

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.54

Position offset: -25

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