chr7-128392870-C-G

Position:

• chr7-128392870-C-G

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_Strong BS1_Supporting BS2

The NM_000883.4(IMPDH1):​c.*137G>C variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000458 in 837,850 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.00029 (1 hom., cov: 33)
  • Exomes 𝑓: 0.00050 (2 hom.)
• Consequence: IMPDH1 NM_000883.4 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: 2.24

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]

ACMG classification

Verdict is Benign. Variant got -9 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.79).
• BS1: Variant frequency is greater than expected in population sas. gnomad4 allele frequency = 0.000289 (44/152234) while in subpopulation SAS AF= 0.00332 (16/4826). AF 95% confidence interval is 0.00208. There are 1 homozygotes in gnomad4. There are 23 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAd4 at 44 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IMPDH1	NM_000883.4	c.*137G>C		3_prime_UTR_variant	17/17	ENST00000338791.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IMPDH1	ENST00000338791.11	c.*137G>C		3_prime_UTR_variant	17/17	2	NM_000883.4

Frequencies

GnomAD3 genomes AF: 0.000289 AC: 44 AN: 152116 Hom.: 1 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00288

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00331

Gnomad FIN AF: 0.0000942

Gnomad MID AF: 0.00316

Gnomad NFE AF: 0.000221

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.000496 AC: 340 AN: 685616 Hom.: 2 Cov.: 9 AF XY: 0.000627 AC XY: 226 AN XY: 360484

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000166

Gnomad4 ASJ exome AF: 0.00268

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00266

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000216

Gnomad4 OTH exome AF: 0.000497

GnomAD4 genome AF: 0.000289 AC: 44 AN: 152234 Hom.: 1 Cov.: 33 AF XY: 0.000309 AC XY: 23 AN XY: 74426

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00288

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00332

Gnomad4 FIN AF: 0.0000942

Gnomad4 NFE AF: 0.000221

Gnomad4 OTH AF: 0.00

Bravo AF: 0.000264

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

Leber congenital amaurosis 11 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 27, 2017

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

Retinitis pigmentosa Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 27, 2017

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.79
CADD	Benign	11
DANN	Benign	0.72
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

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

LitVar

Other links and lift over

dbSNP: rs72624973; hg19: chr7-128032924;