chrX-149490313-C-A

Position:

• chrX-149490313-C-A

Variant summary

Our verdict is Pathogenic. Variant got 22 ACMG points: 22P and 0B. PVS1 PM2 PP3_Strong PP5_Very_Strong

The NM_000202.8(IDS):​c.1006+1G>T variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency: Genomes: not found (cov: 23)
• Consequence: IDS NM_000202.8 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.31

Genes affected

IDS (HGNC:5389): (iduronate 2-sulfatase) This gene encodes a member of the sulfatase family of proteins. The encoded preproprotein is proteolytically processed to generate two polypeptide chains. This enzyme is involved in the lysosomal degradation of heparan sulfate and dermatan sulfate. Mutations in this gene are associated with the X-linked lysosomal storage disease mucopolysaccharidosis type II, also known as Hunter syndrome. Alternative splicing results in multiple transcript variants, at least one of which encodes a preproprotein that is proteolytically processed. [provided by RefSeq, Jan 2016]

ACMG classification

Verdict is Pathogenic. Variant got 22 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 10, offset of 22, new splice context is: ctgGTgagt. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant X-149490313-C-A is Pathogenic according to our data. Variant chrX-149490313-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 221978.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chrX-149490313-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
IDS	NM_000202.8	c.1006+1G>T		splice_donor_variant		ENST00000340855.11
IDS	NM_001166550.4	c.736+1G>T		splice_donor_variant
IDS	NM_006123.5	c.1006+1G>T		splice_donor_variant
IDS	NR_104128.2	n.1305+1G>T		splice_donor_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IDS	ENST00000340855.11	c.1006+1G>T		splice_donor_variant		1	NM_000202.8	P1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Mucopolysaccharidosis, MPS-II Pathogenic:2

Pathogenic, criteria provided, single submitter	research	MOLECULAR BIOLOGY LABORATORY, INSTITUTO NACIONAL DE PEDIATRIA	Oct 18, 2015	Pathogenic variation identified in a Hunter syndrome male patient with I2S deficiency. He presents mental retardation, but no seizures, nor hydrocephaly. -
Pathogenic, criteria provided, single submitter	literature only	Laboratory of Diagnosis and Therapy of Lysosomal Disorders, University of Padova	Jun 07, 2024	Null variant (PVS1_VeryStrong), Absent from controls (or at low frequency) in gnomAD database (PM2_Moderate), Patient’s phenotype or family history highly specific for the disease (PP4_Strong) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.74	D
BayesDel_noAF	Pathogenic	0.18
CADD	Pathogenic	35
DANN	Uncertain	1.0
FATHMM_MKL	Pathogenic	0.98	D
MutationTaster	Benign	1.0	D;D;D;D
GERP RS		4.7

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_DG_spliceai		0.99		Position offset: -21
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: rs869025308; hg19: chrX-148571844;