13-48233403-G-A

Position:

• chr13-48233403-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_021999.5(ITM2B):​c.43G>A​(p.Ala15Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000708 in 1,411,496 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another nucleotide change resulting in same amino acid change has been previously reported as Likely benignin UniProt.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 7.1e-7 (0 hom.)
• Consequence: ITM2B NM_021999.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.64

Genes affected

ITM2B (HGNC:6174): (integral membrane protein 2B) Amyloid precursor proteins are processed by beta-secretase and gamma-secretase to produce beta-amyloid peptides which form the characteristic plaques of Alzheimer disease. This gene encodes a transmembrane protein which is processed at the C-terminus by furin or furin-like proteases to produce a small secreted peptide which inhibits the deposition of beta-amyloid. Mutations which result in extension of the C-terminal end of the encoded protein, thereby increasing the size of the secreted peptide, are associated with two neurogenerative diseases, familial British dementia and familial Danish dementia. [provided by RefSeq, Oct 2009]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.14478719).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ITM2B	NM_021999.5	c.43G>A	p.Ala15Thr	missense_variant	1/6	ENST00000647800.2	NP_068839.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ITM2B	ENST00000647800.2	c.43G>A	p.Ala15Thr	missense_variant	1/6		NM_021999.5	ENSP00000497221.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 7.08e-7 AC: 1 AN: 1411496 Hom.: 0 Cov.: 30 AF XY: 0.00000143 AC XY: 1 AN XY: 699422

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: 9.18e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 13, 2023

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 15 of the ITM2B protein (p.Ala15Thr). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with ITM2B-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Not Available"; PolyPhen-2: "Benign"; Align-GVGD: "Not Available". The threonine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.079
BayesDel_addAF	Benign	-0.17	T
BayesDel_noAF	Benign	-0.48
CADD	Benign	18
DANN	Uncertain	0.99
DEOGEN2	Benign	0.18	T;.;T
Eigen	Benign	-0.28
Eigen_PC	Benign	-0.16
FATHMM_MKL	Uncertain	0.79	D
LIST_S2	Benign	0.75	.;T;T
M_CAP	Benign	0.052	D
MetaRNN	Benign	0.14	T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.7	L;L;L
PrimateAI	Uncertain	0.77	T
PROVEAN	Benign	-1.1	N;N;.
REVEL	Benign	0.012
Sift	Benign	0.38	T;T;.
Sift4G	Benign	0.57	T;T;.
Polyphen		0.26	B;.;B
Vest4		0.17
MutPred		0.23		Gain of phosphorylation at A15 (P = 0.0119);Gain of phosphorylation at A15 (P = 0.0119);Gain of phosphorylation at A15 (P = 0.0119);
MVP		0.37
MPC		0.43
ClinPred		0.35	T
GERP RS		3.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6
Varity_R		0.085
gMVP		0.27

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: rs11556905; hg19: chr13-48807539;