4-1003120-C-G

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PS3_SupportingPP4_ModeratePM2_SupportingPP3PM3_Strong

This summary comes from the ClinGen Evidence Repository: The NM_000203.5:c.1487C>G variant in IDUA is a missense variant predicted to cause substitution of Proline by Arginine at amino acid 496 p.(Pro496Arg). At least 8 patients are compound heterozygous for the variant and another variant in IDUA that has been classified as pathogenic or likely pathogenic by the ClinGen LD VCEP including c.793G>C (p.Gly265Arg) (ClinVar Variation ID: 638074) (PMID:21394825, LP, 0.25), c.152G>A (p.Gly51Asp) (ClinVar Variation ID: 193061) (PMID:21394825, P, 2 x 0.5), c.208C>T (p.Gln70Ter) (ClinVar Variation ID: 11909) (PMID:21394825, P, 4 patients, max 2 x 0.5), and c.1598C>G (p.Pro533Arg) (PMID:34408967, P, 0.5 points). One individual is homozygous for the variant (PMID:34408967, 0.5 points). This variant has also been reported in compound heterozygosity with p.Arg89Trp (PMID:21394825), c.1727+1G>A (PMID:21394825), c.1854C>A (p.Tyr618Ter) (PMID:27520059) and c.878_889dup (PMID 28752568). The allelic data from these patients will be used in the subsequent classification of then second variant and is not included here to avoid circular logic. Total 3.25 points (PM3_Strong). In one report (PMID:27520059), there was evidence of decreased IDUA enzyme activity, increased urine glycosaminoglycans and a specific clinical phenotype, allowing for application of PP4_Moderate. The highest population minor allele frequency in gnomAD v4.1.0. is 0.000003515 (4/1137936 alleles) in the European (non-Finnish) population, which is lower than the ClinGen Lysosomal Diseases VCEP’s threshold for PM2_Supporting (<0.00025), meeting this criterion (PM2_Supporting). and has some experimental evidence suggesting absence of IDUA activity when the variant is expressed in Cos-7 cells (PMID:11735025) (PS3_Supporting). Computational predictor tools (REVEL score 0.72) suggest that this variant may be deleterious to IDUA function (PP3). A different missense variant, c.1487C>G (p.Pro496Leu) [ClinVar Variation ID 551675] in the same codon has been classified as likely pathogenic for MPS I by the ClinGen VCEP, however PM5 was not assigned to avoid circular logic. There is a ClinVar entry for this variant (Variation ID: 496861). In summary, this variant meets the criteria to be classified as likely pathogenic for MPS I based on the ACMG/AMP criteria applied, as specified by the ClinGen Lysosomal Diseases Variant Curation Expert panel: PM3_Strong, PP4_Moderate. PS3_Supporting, PM2_Supporting, PP3.(Classification approved by the ClinGen Lysosomal Diseases Variant Curation Expert Panel on December 5, 2024) LINK:https://erepo.genome.network/evrepo/ui/classification/CA2802275/MONDO:0001586/091

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000022 ( 0 hom. )

Consequence

IDUA
NM_000203.5 missense

Scores

Clinical Significance

Likely pathogenic reviewed by expert panel P:10

Conservation

PhyloP100: 2.63

Publications

10 publications found

Variant links:

Genes affected

IDUA (HGNC:5391): (alpha-L-iduronidase) This gene encodes an enzyme that hydrolyzes the terminal alpha-L-iduronic acid residues of two glycosaminoglycans, dermatan sulfate and heparan sulfate. This hydrolysis is required for the lysosomal degradation of these glycosaminoglycans. Mutations in this gene that result in enzymatic deficiency lead to the autosomal recessive disease mucopolysaccharidosis type I (MPS I). [provided by RefSeq, Jul 2008]

IDUA Gene-Disease associations (from GenCC):

mucopolysaccharidosis type 1
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen, Myriad Women’s Health
Scheie syndrome
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae), Orphanet
Hurler syndrome
Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, PanelApp Australia
Hurler-Scheie syndrome
Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet

IDUA links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

PS3

For more information check the summary or visit ClinGen Evidence Repository.

PM2

For more information check the summary or visit ClinGen Evidence Repository.

PM3

For more information check the summary or visit ClinGen Evidence Repository.

PP3

For more information check the summary or visit ClinGen Evidence Repository.

PP4

For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IDUA	NM_000203.5 link	c.1487C>G	p.Pro496Arg	missense_variant	Exon 10 of 14	ENST00000514224.2	NP_000194.2	P35475-1
IDUA	NM_001363576.1 link	c.1091C>G	p.Pro364Arg	missense_variant	Exon 9 of 13		NP_001350505.1
IDUA	XM_047415650.1 link	c.1487C>G	p.Pro496Arg	missense_variant	Exon 10 of 12		XP_047271606.1
IDUA	NR_110313.1 link	n.1575C>G		non_coding_transcript_exon_variant	Exon 10 of 14

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IDUA	ENST00000514224.2 link	c.1487C>G	p.Pro496Arg	missense_variant	Exon 10 of 14	2	NM_000203.5	ENSP00000425081.2		P35475-1

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

151960

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

GnomAD2 exomes

AF:

0.0000139

AC:

AN:

143870

AF XY:

0.0000241

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000299

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000221

AC:

AN:

1359134

Hom.:

Cov.:

AF XY:

0.00000148

AC XY:

AN XY:

674164

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

28350

American (AMR)

AF:

0.00

AC:

AN:

33442

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

23802

East Asian (EAS)

AF:

0.00

AC:

AN:

31192

South Asian (SAS)

AF:

0.00

AC:

AN:

75728

European-Finnish (FIN)

AF:

0.00

AC:

AN:

35184

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5362

European-Non Finnish (NFE)

AF:

0.00000280

AC:

AN:

1069986

Other (OTH)

AF:

0.00

AC:

AN:

56088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.442

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000658

AC:

AN:

151960

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74216

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41414

American (AMR)

AF:

0.00

AC:

AN:

15266

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5170

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10542

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

67950

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ExAC

AF:

0.0000263

AC:

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:10

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

Mucopolysaccharidosis type 1

Pathogenic:6

Sep 16, 2020

Natera, Inc.

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Apr 24, 2018

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

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: IDUA c.1487C>G (p.Pro496Arg) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was observed with an allele frequency of 1.4e-05 in 145584 control chromosomes (gnomAD). This frequency is not significantly higher than expected for a pathogenic variant in IDUA causing Mucopolysaccharidosis Type 1 (1.4e-05 vs 0.0027), allowing no conclusion about variant significance. The variant, c.1487C>G, has been reported in the literature in multiple individuals affected with Mucopolysaccharidosis Type 1 (Beesley_2001, Bertola_2011). These data indicate that the variant is very likely to be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in <10% of normal activity. A ClinVar submission from a clinical diagnostic laboratory (evaluation after 2014) cites the variant as "pathogenic."Based on the evidence outlined above, the variant was classified as pathogenic. -

Jan 11, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces proline, which is neutral and non-polar, with arginine, which is basic and polar, at codon 496 of the IDUA protein (p.Pro496Arg). This variant is present in population databases (rs772416503, gnomAD 0.003%). This missense change has been observed in individual(s) with Hurler syndrome (PMID: 21394825, 27520059). ClinVar contains an entry for this variant (Variation ID: 496861). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt IDUA protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects IDUA function (PMID: 11735025). For these reasons, this variant has been classified as Pathogenic. -

Jan 13, 2020

Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:curation

The p.Pro496Arg variant in IDUA has been reported in at least 13 individuals with mucopolysaccharidosis (MPS) (PMID: 21394825, 28752568, 27520059) and has been identified in 0.003% (2/66872) of European (non-Finnish) chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs772416503). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. This variant has also been reported in ClinVar (VariationID: 496861) as pathogenic by Counsyl, EGL Genetic Diagnostics, and Integrated Genetics. In vitro functional studies provide some evidence that the p.Pro496Arg variant may impact protein function (PMID: 11735025). However, these types of assays may not accurately represent biological function. Computational prediction tools and conservation analyses suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. The presence of this variant in combination with reported pathogenic variants and in at least 8 individuals with MPS increases the likelihood that the p.Pro496Arg variant is pathogenic (VariationID: 193061, 11909, 11908; PMID: 21394825, 28752568). One additional likely pathogenic variant, resulting in a different amino acid change at the same position, p.Pro496Leu, has been reported in association with disease in the literature and ClinVar, slightly supporting that a change at this position may not be tolerated (PMID: 7550232; Variation ID: 551675). In summary, this variant meets criteria to be classified as pathogenic for MPS in an autosomal recessive manner based on its presence in combination with other pathogenic variants in individuals with MPS and functional studies. ACMG/AMP Criteria applied: PM3_very-strong, PM2, PS3_moderate, PP3 (Richards 2015). -

Dec 05, 2024

ClinGen Lysosomal Storage Disorder Variant Curation Expert Panel

Significance:Likely pathogenic

Review Status:reviewed by expert panel

Collection Method:curation

The NM_000203.5:c.1487C>G variant in IDUA is a missense variant predicted to cause substitution of Proline by Arginine at amino acid 496 p.(Pro496Arg). At least 8 patients are compound heterozygous for the variant and another variant in IDUA that has been classified as pathogenic or likely pathogenic by the ClinGen LD VCEP including c.793G>C (p.Gly265Arg) (ClinVar Variation ID: 638074) (PMID: 21394825, LP, 0.25), c.152G>A (p.Gly51Asp) (ClinVar Variation ID: 193061) (PMID: 21394825, P, 2 x 0.5), c.208C>T (p.Gln70Ter) (ClinVar Variation ID: 11909) (PMID: 21394825, P, 4 patients, max 2 x 0.5), and c.1598C>G (p.Pro533Arg) (PMID: 34408967, P, 0.5 points). One individual is homozygous for the variant (PMID: 34408967, 0.5 points). This variant has also been reported in compound heterozygosity with p.Arg89Trp (PMID: 21394825), c.1727+1G>A (PMID: 21394825), c.1854C>A (p.Tyr618Ter) (PMID: 27520059) and c.878_889dup (PMID 28752568). The allelic data from these patients will be used in the subsequent classification of then second variant and is not included here to avoid circular logic. Total 3.25 points (PM3_Strong). In one report (PMID: 27520059), there was evidence of decreased IDUA enzyme activity, increased urine glycosaminoglycans and a specific clinical phenotype, allowing for application of PP4_Moderate. The highest population minor allele frequency in gnomAD v4.1.0. is 0.000003515 (4/1137936 alleles) in the European (non-Finnish) population, which is lower than the ClinGen Lysosomal Diseases VCEP’s threshold for PM2_Supporting (<0.00025), meeting this criterion (PM2_Supporting). and has some experimental evidence suggesting absence of IDUA activity when the variant is expressed in Cos-7 cells (PMID: 11735025) (PS3_Supporting). Computational predictor tools (REVEL score 0.72) suggest that this variant may be deleterious to IDUA function (PP3). A different missense variant, c.1487C>G (p.Pro496Leu) [ClinVar Variation ID 551675] in the same codon has been classified as likely pathogenic for MPS I by the ClinGen VCEP, however PM5 was not assigned to avoid circular logic. There is a ClinVar entry for this variant (Variation ID: 496861). In summary, this variant meets the criteria to be classified as likely pathogenic for MPS I based on the ACMG/AMP criteria applied, as specified by the ClinGen Lysosomal Diseases Variant Curation Expert panel: PM3_Strong, PP4_Moderate. PS3_Supporting, PM2_Supporting, PP3. (Classification approved by the ClinGen Lysosomal Diseases Variant Curation Expert Panel on December 5, 2024) -

Jan 01, 2019

Laboratory of Diagnosis and Therapy of Lysosomal Disorders, University of Padova

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:literature only

PS3: Low in vitro enzymatic activity. PM2: Very low frequency in ExAC. PP3: Multiple lines of computational evidence supporting a deleterious effect -

not provided

Pathogenic:2

Jul 15, 2022

Revvity Omics, Revvity

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 30, 2017

Eurofins Ntd Llc (ga)

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Hurler syndrome

Pathogenic:1

Mar 21, 2017

Counsyl

Significance:Pathogenic

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. -

Mucopolysaccharidosis, MPS-I-S;C0086431:Mucopolysaccharidosis, MPS-I-H/S;C0086795:Hurler syndrome

Pathogenic:1

May 06, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.90

BayesDel_addAF

Pathogenic

0.28

BayesDel_noAF

Pathogenic

0.25

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.97

D;.

Eigen

Uncertain

0.47

Eigen_PC

Uncertain

0.32

FATHMM_MKL

Uncertain

0.84

LIST_S2

Uncertain

0.88

D;.

M_CAP

Pathogenic

0.85

MetaRNN

Pathogenic

0.97

D;D

MetaSVM

Pathogenic

0.99

MutationAssessor

Uncertain

2.7

M;.

PhyloP100

2.6

PrimateAI

Pathogenic

0.88

PROVEAN

Pathogenic

-7.6

D;D

REVEL

Pathogenic

0.72

Sift

Uncertain

0.0020

D;D

Sift4G

Pathogenic

0.0

D;D

Polyphen

1.0

D;.

Vest4

0.85

MVP

0.99

MPC

0.75

ClinPred

0.99

GERP RS

3.9

Varity_R

0.93

gMVP

0.94

Mutation Taster

=3/97

disease causing (ClinVar)

(source)

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

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over