2-167869409-C-T

Variant summary

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

The NM_020981.4(B3GALT1):c.370C>T(p.Pro124Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,874 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 (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: B3GALT1 NM_020981.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.02

Genes affected

B3GALT1 (HGNC:916): (beta-1,3-galactosyltransferase 1) This gene is a member of the beta-1,3-galactosyltransferase (beta3GalT) gene family. This family encodes type II membrane-bound glycoproteins with diverse enzymatic functions using different donor substrates (UDP-galactose and UDP-N-acetylglucosamine) and different acceptor sugars (N-acetylglucosamine, galactose, N-acetylgalactosamine). The beta3GalT genes are distantly related to the Drosophila Brainiac gene and have the protein coding sequence contained in a single exon. The beta3GalT proteins also contain conserved sequences not found in the beta4GalT or alpha3GalT proteins. The carbohydrate chains synthesized by these enzymes are designated as type 1, whereas beta4GalT enzymes synthesize type 2 carbohydrate chains. The ratio of type 1:type 2 chains changes during embryogenesis. By sequence similarity, the beta3GalT genes fall into at least two groups: beta3GalT4 and 4 other beta3GalT genes (beta3GalT1-3, beta3GalT5). This gene is expressed exclusively in the brain. The encoded protein shows strict donor substrate specificity for UDP-galactose. [provided by RefSeq, Jul 2008]

B3GALT1-AS1 (HGNC:40089): (B3GALT1 antisense RNA 1)

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=0.15950388).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
B3GALT1	NM_020981.4	c.370C>T	p.Pro124Ser	missense_variant	5/5	ENST00000392690.4
B3GALT1-AS1	NR_131227.1	n.328+331G>A		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
B3GALT1	ENST00000392690.4	c.370C>T	p.Pro124Ser	missense_variant	5/5		NM_020981.4	P1
B3GALT1-AS1	ENST00000430546.2	n.362+331G>A		intron_variant, non_coding_transcript_variant		3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461874 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727230

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

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

Jan 26, 2023

The c.370C>T (p.P124S) alteration is located in exon 2 (coding exon 1) of the B3GALT1 gene. This alteration results from a C to T substitution at nucleotide position 370, causing the proline (P) at amino acid position 124 to be replaced by a serine (S). 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	0.082
BayesDel_addAF	Benign	-0.20	T
BayesDel_noAF	Benign	-0.52
Cadd	Benign	21
Dann	Benign	0.95
DEOGEN2	Benign	0.044	T
Eigen	Benign	-0.015
Eigen_PC	Benign	0.19
FATHMM_MKL	Uncertain	0.77	D
LIST_S2	Uncertain	0.88	D
M_CAP	Benign	0.0069	T
MetaRNN	Benign	0.16	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.49	N
MutationTaster	Benign	0.99	D;D
PrimateAI	Uncertain	0.67	T
PROVEAN	Benign	-0.76	N
REVEL	Benign	0.062
Sift	Benign	0.69	T
Sift4G	Benign	0.75	T
Polyphen		0.24	B
Vest4		0.11
MutPred		0.30		Gain of helix (P = 0.0696);
MVP		0.57
MPC		0.48
ClinPred		0.56	D
GERP RS		5.3
Varity_R		0.097
gMVP		0.43

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: rs762733734; hg19: chr2-168725919;