NM_006876.3:c.170A>C

Variant names:

• chr11-66347376-T-G
• rs1555016653
• NM_006876.3:c.170A>C

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_006876.3(B4GAT1):​c.170A>C​(p.Asp57Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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)
• Consequence: B4GAT1 NM_006876.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.677
• Publications: 0 publications found

Genes affected

B4GAT1 (HGNC:15685): (beta-1,4-glucuronyltransferase 1) This gene encodes a member of the beta-1,3-N-acetylglucosaminyltransferase family. This enzyme is a type II transmembrane protein. It is essential for the synthesis of poly-N-acetyllactosamine, a determinant for the blood group i antigen. [provided by RefSeq, Jul 2008]

B4GAT1 Gene-Disease associations (from GenCC):

• muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type A13

  Inheritance: AR Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), ClinGen
• muscular dystrophy-dystroglycanopathy, type A

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.086601764).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
B4GAT1	NM_006876.3	c.170A>C	p.Asp57Ala	missense_variant	Exon 1 of 2	ENST00000311181.5	NP_006867.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
B4GAT1	ENST00000311181.5	c.170A>C	p.Asp57Ala	missense_variant	Exon 1 of 2	1	NM_006876.3	ENSP00000309096.4

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 A13 Uncertain:1

Jan 08, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces aspartic acid, which is acidic and polar, with alanine, which is neutral and non-polar, at codon 57 of the B4GAT1 protein (p.Asp57Ala). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with B4GAT1-related conditions. ClinVar contains an entry for this variant (Variation ID: 541279). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt B4GAT1 protein function with a negative predictive value of 80%. 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	0.12
BayesDel_addAF	Benign	-0.19	T
BayesDel_noAF	Benign	-0.52
CADD	Benign	20
DANN	Uncertain	0.98
DEOGEN2	Benign	0.13	T
Eigen	Benign	-0.55
Eigen_PC	Benign	-0.40
FATHMM_MKL	Benign	0.30	N
LIST_S2	Benign	0.67	T
M_CAP	Benign	0.026	D
MetaRNN	Benign	0.087	T
MetaSVM	Benign	-0.97	T
PhyloP100		0.68
PrimateAI	Uncertain	0.64	T
PROVEAN	Benign	-0.76	N
REVEL	Benign	0.046
Sift	Uncertain	0.012	D
Sift4G	Benign	0.099	T
Polyphen		0.0	B
Vest4		0.16
MutPred		0.29		Loss of loop (P = 0.0073);
MVP		0.14
MPC		1.0
ClinPred		0.16	T
GERP RS		2.7
PromoterAI		0.068	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.21
gMVP		0.79
Mutation Taster		=80/20	polymorphism

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

Other links and lift over

dbSNP: rs1555016653; hg19: chr11-66114847;