1-43981204-C-T

Position:

• chr1-43981204-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_003780.5(B4GALT2):​c.44C>T​(p.Ala15Val) variant causes a missense change. The variant allele was found at a frequency of 0.000000689 in 1,450,724 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: B4GALT2 NM_003780.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.53

Genes affected

B4GALT2 (HGNC:925): (beta-1,4-galactosyltransferase 2) This gene is one of seven beta-1,4-galactosyltransferase (beta4GalT) genes. They encode type II membrane-bound glycoproteins that appear to have exclusive specificity for the donor substrate UDP-galactose; all transfer galactose in a beta1,4 linkage to similar acceptor sugars: GlcNAc, Glc, and Xyl. Each beta4GalT has a distinct function in the biosynthesis of different glycoconjugates and saccharide structures. As type II membrane proteins, they have an N-terminal hydrophobic signal sequence that directs the protein to the Golgi apparatus and which then remains uncleaved to function as a transmembrane anchor. By sequence similarity, the beta4GalTs form four groups: beta4GalT1 and beta4GalT2, beta4GalT3 and beta4GalT4, beta4GalT5 and beta4GalT6, and beta4GalT7. The enzyme encoded by this gene synthesizes N-acetyllactosamine in glycolipids and glycoproteins. Its substrate specificity is affected by alpha-lactalbumin but it is not expressed in lactating mammary tissue. Three transcript variants encoding two different isoforms have been found for this gene. [provided by RefSeq, Jul 2011]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.31628916).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
B4GALT2	NM_003780.5	c.44C>T	p.Ala15Val	missense_variant	2/7	ENST00000372324.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
B4GALT2	ENST00000372324.6	c.44C>T	p.Ala15Val	missense_variant	2/7	1	NM_003780.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.89e-7 AC: 1 AN: 1450724 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 722174

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

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

May 14, 2024

The c.131C>T (p.A44V) alteration is located in exon 2 (coding exon 2) of the B4GALT2 gene. This alteration results from a C to T substitution at nucleotide position 131, causing the alanine (A) at amino acid position 44 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.19
BayesDel_addAF	Benign	-0.11	T
BayesDel_noAF	Benign	-0.39
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.034	T;T;.
Eigen	Uncertain	0.31
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Uncertain	0.91	D;.;D
M_CAP	Benign	0.013	T
MetaRNN	Benign	0.32	T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.69	N;N;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Benign	0.29	N;N;N
REVEL	Benign	0.060
Sift	Benign	0.16	T;T;T
Sift4G	Benign	0.43	T;T;T
Polyphen		0.85	P;P;.
Vest4		0.57
MutPred		0.35		Loss of ubiquitination at K14 (P = 0.1172);Loss of ubiquitination at K14 (P = 0.1172);.;
MVP		0.47
MPC		1.1
ClinPred		0.65	D
GERP RS		5.0
Varity_R		0.089
gMVP		0.72

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs894020408; hg19: chr1-44446876; COSMIC: COSV52544174; COSMIC: COSV52544174;