NM_000203.5:c.265C>T

Variant names:

• chr4-987915-C-T
• rs754966840
• NM_000203.5:c.265C>T

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2 PP3_Strong PP5_Very_Strong

The NM_000203.5(IDUA):​c.265C>T​(p.Arg89Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000103 in 1,450,156 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 (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000010 (0 hom.)
• Consequence: IDUA NM_000203.5 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 0.936

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]

SLC26A1 (HGNC:10993): (solute carrier family 26 member 1) This gene is a member of a family of sulfate/anion transporter genes. Family members are well conserved in their genomic (number and size of exons) and protein (aa length among species) structures, but have markedly different tissue expression patterns. This gene is primarily expressed in the liver, pancreas, and brain. Three splice variants that encode different isoforms have been identified. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992
• PP5: Variant 4-987915-C-T is Pathogenic according to our data. Variant chr4-987915-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 580286.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
IDUA	NM_000203.5	c.265C>T	p.Arg89Trp	missense_variant	Exon 2 of 14	ENST00000514224.2	NP_000194.2
SLC26A1	NM_022042.4	c.*918G>A		3_prime_UTR_variant	Exon 3 of 3	ENST00000398516.3	NP_071325.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IDUA	ENST00000514224.2	c.265C>T	p.Arg89Trp	missense_variant	Exon 2 of 14	2	NM_000203.5	ENSP00000425081.2
SLC26A1	ENST00000398516	c.*918G>A		3_prime_UTR_variant	Exon 3 of 3	1	NM_022042.4	ENSP00000381528.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000136 AC: 3 AN: 221242 Hom.: 0 AF XY: 0.0000166 AC XY: 2 AN XY: 120434

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000308

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000352

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000104

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000103 AC: 15 AN: 1450156 Hom.: 0 Cov.: 30 AF XY: 0.00000972 AC XY: 7 AN XY: 720470

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000231

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000354

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000723

Gnomad4 OTH exome AF: 0.0000500

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ExAC AF: 0.00000831 AC: 1

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Mucopolysaccharidosis type 1 Pathogenic:3

Jul 13, 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 tryptophan, which is neutral and slightly polar, at codon 89 of the IDUA protein (p.Arg89Trp). This variant is present in population databases (rs754966840, gnomAD 0.007%). This missense change has been observed in individuals with MPS I (PMID: 7550242, 14559116, 21394825, 22306676, 24368159, 27896125). ClinVar contains an entry for this variant (Variation ID: 580286). 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: 14559116). This variant disrupts the p.Arg89 amino acid residue in IDUA. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 8664897, 12559846, 14559116). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Nov 14, 2020

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Apr 30, 2019

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.265C>T (p.Arg89Trp) 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 allele was found at a frequency of 1.4e-05 in 221338 control chromosomes (gnomAD and publication data) and has been reported in the literature in multiple individuals affected with Mucopolysaccharidosis Type 1 (e.g. Bunge_1995, Bertola_2011, Ahmed_2014, Pineda 2014) and most of the cases presented with an attenuated- (Scheie syndrome) or intermediate phenotype (Hurler-Scheie syndrome). These data indicate that the variant is very likely to be associated with disease. Functional characterization demonstrated the variant protein was present in a similar- or increased amount in cell lines from patients compared to controls, but had a severely reduced enzymatic activity in both patient derived cell lines and transfected Chinese hamster ovary cells (Bunge_1998, Hein_2003); since some residual activity was preserved, it is consistent with the less severe clinical presentation of the reported patients (Hein_2003). One submitter has provided clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation, and classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

not provided Pathogenic:1

Dec 02, 2021

Revvity Omics, Revvity

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

Mar 22, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.84
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.48
CADD	Pathogenic	34
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D
Eigen	Uncertain	0.35
Eigen_PC	Benign	0.20
FATHMM_MKL	Benign	0.23	N
LIST_S2	Uncertain	0.96	D
M_CAP	Pathogenic	0.84	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.7	M
PrimateAI	Uncertain	0.71	T
PROVEAN	Pathogenic	-6.2	D
REVEL	Pathogenic	0.89
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.96
MutPred		0.95		Loss of glycosylation at K86 (P = 0.0815);
MVP		1.0
MPC		0.77
ClinPred		0.98	D
GERP RS		2.5
Varity_R		0.87
gMVP		0.97

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.080		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: rs754966840; hg19: chr4-981703;