17-75752189-T-C

Position:

• chr17-75752189-T-C

Variant summary

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

The NM_000213.5(ITGB4):​c.3809T>C​(p.Met1270Thr) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,622 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M1270I) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ITGB4 NM_000213.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.86

Genes affected

ITGB4 (HGNC:6158): (integrin subunit beta 4) Integrins are heterodimers comprised of alpha and beta subunits, that are noncovalently associated transmembrane glycoprotein receptors. Different combinations of alpha and beta polypeptides form complexes that vary in their ligand-binding specificities. Integrins mediate cell-matrix or cell-cell adhesion, and transduced signals that regulate gene expression and cell growth. This gene encodes the integrin beta 4 subunit, a receptor for the laminins. This subunit tends to associate with alpha 6 subunit and is likely to play a pivotal role in the biology of invasive carcinoma. Mutations in this gene are associated with epidermolysis bullosa with pyloric atresia. Multiple alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

GALK1 (HGNC:4118): (galactokinase 1) Galactokinase is a major enzyme for the metabolism of galactose and its deficiency causes congenital cataracts during infancy and presenile cataracts in the adult population. [provided by RefSeq, Jul 2008]

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=0.22613189).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ITGB4	NM_000213.5	c.3809T>C	p.Met1270Thr	missense_variant	31/40	ENST00000200181.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ITGB4	ENST00000200181.8	c.3809T>C	p.Met1270Thr	missense_variant	31/40	1	NM_000213.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461622 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727106

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Junctional epidermolysis bullosa with pyloric atresia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.23
BayesDel_addAF	Benign	-0.067	T
BayesDel_noAF	Benign	-0.33
CADD	Benign	21
DANN	Benign	0.90
Eigen	Benign	-0.21
Eigen_PC	Benign	0.015
FATHMM_MKL	Uncertain	0.80	D
M_CAP	Benign	0.020	T
MetaRNN	Benign	0.23	T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	-0.27	N;N;N;N
MutationTaster	Benign	1.0	D;D;D;D;D;D
PrimateAI	Uncertain	0.54	T
Sift4G	Benign	0.37	T;T;T;T
Polyphen		0.012, 0.0030	.;B;.;B
Vest4		0.28
MutPred		0.54		Gain of glycosylation at M1270 (P = 0.0309);Gain of glycosylation at M1270 (P = 0.0309);Gain of glycosylation at M1270 (P = 0.0309);Gain of glycosylation at M1270 (P = 0.0309);
MVP		0.73
MPC		1.5
ClinPred		0.83	D
GERP RS		5.1
Varity_R		0.47
gMVP		0.39

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: rs886053413; hg19: chr17-73748270;