rs1553342963

Positions:

• chr1-235455602-T-A

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_152490.5(B3GALNT2):​c.1108A>T​(p.Ile370Phe) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: B3GALNT2 NM_152490.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.69

Genes affected

B3GALNT2 (HGNC:28596): (beta-1,3-N-acetylgalactosaminyltransferase 2) This gene encodes a member of the glycosyltransferase 31 family. The encoded protein synthesizes GalNAc:beta-1,3GlcNAc, a novel carbohydrate structure, on N- and O-glycans. Alternatively spliced transcript variants that encode different isoforms have been described. [provided by RefSeq, Mar 2013]

B3GALNT2 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.913

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
B3GALNT2	NM_152490.5	c.1108A>T	p.Ile370Phe	missense_variant	9/12	ENST00000366600.8	NP_689703.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
B3GALNT2	ENST00000366600.8	c.1108A>T	p.Ile370Phe	missense_variant	9/12	1	NM_152490.5	ENSP00000355559.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type a, 11 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 17, 2017

In summary, this variant has uncertain impact on B3GALNT2 function. The available evidence is currently insufficient to determine its role in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with a B3GALNT2-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces isoleucine with phenylalanine at codon 370 of the B3GALNT2 protein (p.Ile370Phe). The isoleucine residue is moderately conserved and there is a small physicochemical difference between isoleucine and phenylalanine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.22
BayesDel_addAF	Uncertain	0.051	T
BayesDel_noAF	Benign	-0.17
CADD	Pathogenic	28
DANN	Uncertain	0.98
DEOGEN2	Benign	0.078	T
Eigen	Uncertain	0.26
Eigen_PC	Uncertain	0.30
FATHMM_MKL	Pathogenic	0.97	D
M_CAP	Benign	0.017	T
MetaRNN	Pathogenic	0.91	D
MetaSVM	Benign	-0.89	T
MutationAssessor	Benign	1.8	L
PrimateAI	Uncertain	0.60	T
PROVEAN	Benign	-1.9	N
REVEL	Benign	0.21
Sift	Uncertain	0.0080	D
Sift4G	Benign	0.21	T
Polyphen		0.73	P
Vest4		0.82
MutPred		0.77		Loss of catalytic residue at L375 (P = 0.0588);
MVP		0.44
MPC		0.52
ClinPred		0.74	D
GERP RS		5.6
Varity_R		0.12
gMVP		0.82

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.94		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.94		Position offset: 2
DS_DL_spliceai		0.40		Position offset: -43

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1553342963; hg19: chr1-235618914;