4-987086-T-C

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1 PS1_Moderate PM2 PP5_Moderate

The NM_000203.5(IDUA):c.2T>C(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000151 in 1,327,024 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: 0.0000015 (0 hom.)
• Consequence: IDUA NM_000203.5 start_lost
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: -0.260

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.

• PVS1: Start lost variant, no new inframe start found.
• PS1: Another start lost variant in NM_000203.5 (IDUA) was described as [Likely_pathogenic] in ClinVar as 557150
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-987086-T-C is Pathogenic according to our data. Variant chr4-987086-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 639529.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IDUA	NM_000203.5	c.2T>C	p.Met1?	start_lost	1/14	ENST00000514224.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IDUA	ENST00000514224.2	c.2T>C	p.Met1?	start_lost	1/14	2	NM_000203.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000151 AC: 2 AN: 1327024 Hom.: 0 Cov.: 30 AF XY: 0.00000152 AC XY: 1 AN XY: 656556

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: 0.00000190

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ExAC AF: 0.0000197 AC: 2

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Mucopolysaccharidosis type 1 Pathogenic:2

Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Jul 16, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Aug 31, 2023	This sequence change affects the initiator methionine of the IDUA mRNA. The next in-frame methionine is located at codon 133. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. Disruption of the initiator codon has been observed in individuals with mucopolysaccharidosis type I (PMID: 21480867). ClinVar contains an entry for this variant (Variation ID: 639529). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.30
Cadd	Benign	13
Dann	Benign	0.75
DEOGEN2	Benign	0.22	T;.
Eigen	Benign	-0.77
Eigen_PC	Benign	-0.83
FATHMM_MKL	Benign	0.16	N
LIST_S2	Uncertain	0.90	D;D
M_CAP	Pathogenic	0.99	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Uncertain	0.27	D
MutationTaster	Benign	1.0	D;D;D
PROVEAN	Benign	-1.1	N;N
REVEL	Uncertain	0.55
Sift	Pathogenic	0.0	D;D
Sift4G	Uncertain	0.0070	D;D
Polyphen		0.024	B;.
Vest4		0.51
MutPred		0.99		Loss of glycosylation at P6 (P = 0.0238);Loss of glycosylation at P6 (P = 0.0238);
MVP		0.94
ClinPred		0.32	T
GERP RS		3.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.77
gMVP		0.76

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

LitVar

Other links and lift over

dbSNP: rs753767675; hg19: chr4-980874;