4-1002945-G-A

Position:

• chr4-1002945-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM3 PM2_Supporting PP4 PVS1_Strong

This summary comes from the ClinGen Evidence Repository: The NM_000203.5:c.1402+1G>A variant in IDUA occurs within the canonical splice donor site of intron 9. While the effect of this change has not been proven experimentally, it is predicted to cause skipping of biologically-relevant-exon 9 out of 14 total exons, resulting in an in-frame deletion of amino acids 397-467 which represents >10% of the protein (PVS1_Strong). This variant has been detected in at least two individuals with MPS I. Of those individuals, one was compound heterozygous for the variant and c.502G>T p.(Gly168Ter), which is classified as pathogenic by the ClinGen Lysosomal Diseases VCEP; it is unknown if these variants were confirmed in trans (PMID:33301762). The other individual was homozygous for the variant (PMID:27146977) (PM3). These two patients had documented IDUA deficiency within the affected range in leukocytes and clinical features specific to MPS I including coarse facies, hepatosplenomegaly, corneal opacity, recurrent infections, intellectual disability, hernia, and/or cardiomegaly, cardiomyopathy, and dysostosis multiplex (PP4)(PMIDs: 33301762, 27146977). This variant is absent in gnomAD v4.0. (PM2_Supporting). There is a ClinVar entry for this variant (Variation ID: 555490). In summary, this variant meets the criteria to be classified as likely pathogenic for MPS I based on the IDUA-specific ACMG/AMP criteria applied, as specified by the ClinGen Lysosomal Diseases Variant Curation Expert Panel (Specifications Version 1.0.0): (PVS1_Strong, PM3, PP4, PM2_Supporting).(Classification approved by the ClinGen Lysosomal Diseases Variant Curation Expert Panel on December 5, 2024). LINK:https://erepo.genome.network/evrepo/ui/classification/CA355964379/MONDO:0001586/091

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: IDUA NM_000203.5 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 3.51

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PVS1: 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.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
IDUA	NM_000203.5	c.1402+1G>A		splice_donor_variant, intron_variant		ENST00000514224.2	NP_000194.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
IDUA	ENST00000514224.2	c.1402+1G>A		splice_donor_variant, intron_variant		2	NM_000203.5	ENSP00000425081.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1209636 Hom.: 0 Cov.: 36 AF XY: 0.00 AC XY: 0 AN XY: 586794

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hurler syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Counsyl

Dec 06, 2017

- -

Mucopolysaccharidosis, MPS-I-S;C0086431:Mucopolysaccharidosis, MPS-I-H/S;C0086795:Hurler syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Mar 24, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Benign	-0.18
CADD	Pathogenic	27
DANN	Uncertain	0.98
Eigen	Pathogenic	0.71
Eigen_PC	Uncertain	0.45
FATHMM_MKL	Benign	0.58	D
GERP RS		4.3

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_spliceai		1.0		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs398123254; hg19: chr4-996733;