chr6-131583862-G-A

Variant names:

• chr6-131583862-G-A
• rs377280518
• NM_000045.4:c.923G>A

Variant summary

Our verdict is Pathogenic. The variant received 14 ACMG points: 14P and 0B. PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_000045.4(ARG1):​c.923G>A​(p.Arg308Gln) variant causes a missense change. The variant allele was found at a frequency of 0.00000867 in 1,613,980 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R308W) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000075 (0 hom.)
• Consequence: ARG1 NM_000045.4 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4 U:1
• Conservation: PhyloP100: 6.08
• Publications: 8 publications found

Genes affected

ARG1 (HGNC:663): (arginase 1) Arginase catalyzes the hydrolysis of arginine to ornithine and urea. At least two isoforms of mammalian arginase exist (types I and II) which differ in their tissue distribution, subcellular localization, immunologic crossreactivity and physiologic function. The type I isoform encoded by this gene, is a cytosolic enzyme and expressed predominantly in the liver as a component of the urea cycle. Inherited deficiency of this enzyme results in argininemia, an autosomal recessive disorder characterized by hyperammonemia. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Sep 2011]

MED23 (HGNC:2372): (mediator complex subunit 23) The activation of gene transcription is a multistep process that is triggered by factors that recognize transcriptional enhancer sites in DNA. These factors work with co-activators to direct transcriptional initiation by the RNA polymerase II apparatus. The protein encoded by this gene is a subunit of the CRSP (cofactor required for SP1 activation) complex, which, along with TFIID, is required for efficient activation by SP1. This protein is also a component of other multisubunit complexes e.g. thyroid hormone receptor-(TR-) associated proteins which interact with TR and facilitate TR function on DNA templates in conjunction with initiation factors and cofactors. This protein also acts as a metastasis suppressor. Several alternatively spliced transcript variants encoding different isoforms have been described for this gene. [provided by RefSeq, Jul 2012]

MED23 Gene-Disease associations (from GenCC):

• intellectual disability, autosomal recessive 18

  Inheritance: AR Classification: STRONG, MODERATE, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P
• syndromic intellectual disability

  Inheritance: AR Classification: MODERATE Submitted by: ClinGen
• autosomal recessive non-syndromic intellectual disability

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr6-131583861-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 1012110.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.869
• PP5: Variant 6-131583862-G-A is Pathogenic according to our data. Variant chr6-131583862-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 550679.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ARG1	NM_000045.4	c.923G>A	p.Arg308Gln	missense_variant	Exon 8 of 8	ENST00000368087.8	NP_000036.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ARG1	ENST00000368087.8	c.923G>A	p.Arg308Gln	missense_variant	Exon 8 of 8	1	NM_000045.4	ENSP00000357066.3

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152168 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000724

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

GnomAD2 exomes AF: 0.00000797 AC: 2 AN: 251066 AF XY: 0.00000737

Gnomad AFR exome AF: 0.0000615

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.0000462

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000752 AC: 11 AN: 1461812 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 727202

African (AFR) AF: 0.0000896 AC: 3 AN: 33476

American (AMR) AF: 0.0000224 AC: 1 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39680

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53406

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000450 AC: 5 AN: 1111980

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152168 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74328

African (AFR) AF: 0.0000724 AC: 3 AN: 41440

American (AMR) AF: 0.00 AC: 0 AN: 15282

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5192

South Asian (SAS) AF: 0.00 AC: 0 AN: 4836

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10604

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68024

Other (OTH) AF: 0.00 AC: 0 AN: 2094

Alfa AF: 0.0000453 Hom.: 0

Bravo AF: 0.0000227

ESP6500AA AF: 0.000227 AC: 1

ESP6500EA AF: 0.00 AC: 0

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4 Uncertain:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Arginase deficiency Pathogenic:4 Uncertain:1

Aug 03, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: ARG1 c.923G>A (p.Arg308Gln) results in a conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 251066 control chromosomes. c.923G>A has been reported in the literature in multiple homozygous and compound heterozygous individuals affected with Arginase Deficiency (e.g., Carvalho_2012, Bakirtzis_2021). These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 34419780, 22959135). Three submitters have cited clinical-significance assessments for this variant to ClinVar after 2014; two submitters classified the variant as pathogenic and one classified it as a variant of uncertain signficance. Based on the evidence outlined above, the variant was classified as pathogenic.

Mar 26, 2024

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

May 28, 2019

Mendelics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Feb 08, 2017

Counsyl

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com.

May 04, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 308 of the ARG1 protein (p.Arg308Gln). This variant is present in population databases (rs377280518, gnomAD 0.008%). This missense change has been observed in individual(s) with argininemia (PMID: 22959135). ClinVar contains an entry for this variant (Variation ID: 550679). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. For these reasons, this variant has been classified as Pathogenic.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.77
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.72	D;.;.
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.96	D;D;D
M_CAP	Uncertain	0.25	D
MetaRNN	Pathogenic	0.87	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.7	M;.;.
PhyloP100		6.1
PrimateAI	Benign	0.39	T
PROVEAN	Uncertain	-2.6	D;D;.
REVEL	Pathogenic	0.82
Sift	Uncertain	0.0030	D;D;.
Sift4G	Uncertain	0.0060	D;D;.
Vest4		0.72
ClinPred		0.97	D
GERP RS		6.0
Varity_R		0.92
gMVP		0.79
Mutation Taster		=10/90	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs377280518; hg19: chr6-131905002;