chr7-128392784-G-C

Position:

• chr7-128392784-G-C

Variant summary

Our verdict is Benign. Variant got -13 ACMG points: 0P and 13B. BP4_Strong BP6 BS1 BS2

The NM_000883.4(IMPDH1):​c.*223C>G variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000671 in 561,464 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.00093 (0 hom., cov: 33)
  • Exomes 𝑓: 0.00058 (1 hom.)
• Consequence: IMPDH1 NM_000883.4 3_prime_UTR
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: 0.519

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 -13 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.87).
• BP6: Variant 7-128392784-G-C is Benign according to our data. Variant chr7-128392784-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 358868.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=1}.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.000926 (141/152228) while in subpopulation AFR AF= 0.00233 (97/41556). AF 95% confidence interval is 0.00196. There are 0 homozygotes in gnomad4. There are 68 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.
• BS2: High AC in GnomAd4 at 141 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
IMPDH1	NM_000883.4	c.*223C>G		3_prime_UTR_variant	17/17	ENST00000338791.11	NP_000874.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
IMPDH1	ENST00000338791.11	c.*223C>G		3_prime_UTR_variant	17/17	2	NM_000883.4	ENSP00000345096

Frequencies

GnomAD3 genomes AF: 0.000927 AC: 141 AN: 152110 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00234

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000327

Gnomad ASJ AF: 0.00202

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000828

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000353

Gnomad OTH AF: 0.00191

GnomAD4 exome AF: 0.000577 AC: 236 AN: 409236 Hom.: 1 Cov.: 4 AF XY: 0.000673 AC XY: 145 AN XY: 215394

Gnomad4 AFR exome AF: 0.00230

Gnomad4 AMR exome AF: 0.000232

Gnomad4 ASJ exome AF: 0.00199

Gnomad4 EAS exome AF: 0.0000700

Gnomad4 SAS exome AF: 0.00149

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000415

Gnomad4 OTH exome AF: 0.000592

GnomAD4 genome AF: 0.000926 AC: 141 AN: 152228 Hom.: 0 Cov.: 33 AF XY: 0.000914 AC XY: 68 AN XY: 74432

Gnomad4 AFR AF: 0.00233

Gnomad4 AMR AF: 0.000327

Gnomad4 ASJ AF: 0.00202

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000829

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000353

Gnomad4 OTH AF: 0.00189

Alfa AF: 0.000106 Hom.: 0

Bravo AF: 0.00102

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Leber congenital amaurosis 11 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Retinitis pigmentosa Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.87
CADD	Benign	0.59
DANN	Benign	0.54

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs543042380; hg19: chr7-128032838;