4-987085-A-C

Variant names:

• chr4-987085-A-C
• rs1553914737
• NM_000203.5:c.1A>C

Variant summary

Our verdict is Pathogenic. Variant got 20 ACMG points: 20P and 0B. PVS1 PS1_Moderate PM2 PP5_Very_Strong

The NM_000203.5(IDUA):​c.1A>C​(p.Met1?) variant causes a initiator codon change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,136 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: 𝑓 0.0000066 (0 hom., cov: 33)
• Consequence: IDUA NM_000203.5 initiator_codon
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: -1.98

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]

DGKQ (HGNC:2856): (diacylglycerol kinase theta) The protein encoded by this gene contains three cysteine-rich domains, a proline-rich region, and a pleckstrin homology domain with an overlapping Ras-associating domain. It is localized in the speckle domains of the nucleus, and mediates the regeneration of phosphatidylinositol (PI) from diacylglycerol in the PI-cycle during cell signal transduction. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 20 ACMG points.

• PVS1: Start lost variant, next in-frame start position is after 9 pathogenic variants. Next in-frame start position is after 133 codons. Genomic position: 1000893. Lost 0.202 part of the original CDS.
• PS1: Another start lost variant in NM_000203.5 (IDUA) was described as [Pathogenic] in Lovd
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-987085-A-C is Pathogenic according to our data. Variant chr4-987085-A-C is described in ClinVar as [Pathogenic]. Clinvar id is 550458.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.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 14	ENST00000514224.2	NP_000194.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IDUA	ENST00000514224.2	c.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 14	2	NM_000203.5	ENSP00000425081.2

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152028 Hom.: 0 Cov.: 33

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

GnomAD4 exome Cov.: 30

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152136 Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1 AN XY: 74396

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Mucopolysaccharidosis type 1 Pathogenic:2

Jul 14, 2020

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Mar 14, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 550458). Disruption of the initiator codon has been observed in individual(s) with mucopolysaccharidosis type I (PMID: 21394825, 31236806). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. This variant is not present in population databases (gnomAD no frequency). This sequence change affects the initiator methionine of the IDUA mRNA. The next in-frame methionine is located at codon 133. -

Hurler syndrome Pathogenic:1

Jan 19, 2017

Counsyl

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.080
CADD	Benign	12
DANN	Benign	0.66
DEOGEN2	Benign	0.19	T;.
Eigen	Benign	-1.0
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.12	N
LIST_S2	Uncertain	0.90	D;D
M_CAP	Pathogenic	0.99	D
MetaRNN	Pathogenic	0.96	D;D
MetaSVM	Benign	-0.33	T
PROVEAN	Benign	-0.63	N;N
REVEL	Uncertain	0.48
Sift	Pathogenic	0.0	D;D
Sift4G	Benign	0.19	T;D
Polyphen		0.0	B;.
Vest4		0.61
MutPred		0.98		Loss of glycosylation at P6 (P = 0.0238);Loss of glycosylation at P6 (P = 0.0238);
MVP		0.87
ClinPred		0.54	D
GERP RS		-2.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.76
gMVP		0.63

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: rs1553914737; hg19: chr4-980873;