rs1553757628

Positions:

• chr3-4814509-G-A
• chr3-4814509-G-C

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1 PM2 PP2 PP3_Moderate

The NM_001378452.1(ITPR1):​c.7648G>A​(p.Gly2550Arg) variant causes a missense 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. 13/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in same amino acid change has been previously reported as Uncertain significancein ClinVar.

• Frequency:
  • Genomes: not found (cov: 29)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: ITPR1 NM_001378452.1 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:4
• Conservation: PhyloP100: 9.52

Genes affected

ITPR1 (HGNC:6180): (inositol 1,4,5-trisphosphate receptor type 1) This gene encodes an intracellular receptor for inositol 1,4,5-trisphosphate. Upon stimulation by inositol 1,4,5-trisphosphate, this receptor mediates calcium release from the endoplasmic reticulum. Mutations in this gene cause spinocerebellar ataxia type 15, a disease associated with an heterogeneous group of cerebellar disorders. Multiple transcript variants have been identified for this gene. [provided by RefSeq, Nov 2009]

(HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_001378452.1
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, ITPR1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.93

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ITPR1	NM_001378452.1	c.7648G>A	p.Gly2550Arg	missense_variant	58/62	ENST00000649015.2
LOC124906209	XR_007095795.1	n.725-78C>T		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ITPR1	ENST00000649015.2	c.7648G>A	p.Gly2550Arg	missense_variant	58/62		NM_001378452.1
	ENST00000693140.1	n.581+11237C>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1461626 Hom.: 0 Cov.: 38 AF XY: 0.00 AC XY: 0 AN XY: 727082

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.: 29

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:4

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Apr 12, 2023	This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 2487 of the ITPR1 protein (p.Gly2487Arg). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. 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 ITPR1 protein function. ClinVar contains an entry for this variant (Variation ID: 520945). This variant has not been reported in the literature in individuals affected with ITPR1-related conditions. This variant is not present in population databases (gnomAD no frequency). -
Likely pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Dec 20, 2022	Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 34758253) -
Uncertain significance, criteria provided, single submitter	clinical testing	Athena Diagnostics	Sep 11, 2019	- -

Spinocerebellar ataxia type 29 Pathogenic:1

Likely pathogenic, no assertion criteria provided

clinical testing

Genomics England Pilot Project, Genomics England

-

- -

Gillespie syndrome;C1847725:Spinocerebellar ataxia type 15/16;C1861732:Spinocerebellar ataxia type 29 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 15, 2016

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	33
DANN	Pathogenic	1.0
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.90
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	1.0	D;D;D;D;D;D;D;D;D;.;D
M_CAP	Pathogenic	0.85	D
MetaRNN	Pathogenic	0.93	D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-7.8	D;D;.;D;.;D;.;.;.;D;.
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;D;.;D;.;D;.;.;.;D;.
Sift4G	Pathogenic	0.0010	D;D;.;D;.;D;.;.;.;D;.
Polyphen		1.0	.;.;.;.;.;D;.;D;.;.;.
Vest4		0.97
MutPred		0.72		.;.;.;.;.;.;.;Gain of MoRF binding (P = 0.0508);.;.;.;
MVP		0.99
MPC		2.2
ClinPred		1.0	D
GERP RS		4.9
Varity_R		0.93
gMVP		1.0

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: rs1553757628; hg19: chr3-4856193;