3-49532000-C-G

Position:

• chr3-49532000-C-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_004393.6(DAG1):​c.1489C>G​(p.Pro497Ala) variant causes a missense change involving the alteration of a conserved nucleotide. 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: DAG1 NM_004393.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.91

Genes affected

DAG1 (HGNC:2666): (dystroglycan 1) This gene encodes dystroglycan, a central component of dystrophin-glycoprotein complex that links the extracellular matrix and the cytoskeleton in the skeletal muscle. The encoded preproprotein undergoes O- and N-glycosylation, and proteolytic processing to generate alpha and beta subunits. Certain mutations in this gene are known to cause distinct forms of muscular dystrophy. Alternative splicing results in multiple transcript variants, all encoding the same protein. [provided by RefSeq, Nov 2015]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.95

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
DAG1	NM_004393.6	c.1489C>G	p.Pro497Ala	missense_variant	3/3	ENST00000308775.7	NP_004384.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
DAG1	ENST00000308775.7	c.1489C>G	p.Pro497Ala	missense_variant	3/3	1	NM_004393.6	ENSP00000312435.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

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 A9;C4511963:Autosomal recessive limb-girdle muscular dystrophy type 2P Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 08, 2017

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. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has been observed on the opposite chromosome (in trans) from another pathogenic variant in an individual affected with neuromuscular disease (Invitae). This finding is consistent with autosomal recessive inheritance, and suggests that this variant contributes to disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces proline with alanine at codon 497 of the DAG1 protein (p.Pro497Ala). The proline residue is highly conserved and there is a small physicochemical difference between proline and alanine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.55
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.96	D;D;D;D;D;D
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.86
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.93	D;.;.;.;.;.
M_CAP	Pathogenic	0.40	D
MetaRNN	Pathogenic	0.95	D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	2.9	M;M;M;M;M;M
PrimateAI	Uncertain	0.54	T
PROVEAN	Pathogenic	-6.4	D;D;D;D;D;D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;D;D;D;D;D
Sift4G	Uncertain	0.0050	D;D;D;D;D;D
Polyphen		1.0	D;D;D;D;D;D
Vest4		0.85
MutPred		0.73		Loss of loop (P = 0.0128);Loss of loop (P = 0.0128);Loss of loop (P = 0.0128);Loss of loop (P = 0.0128);Loss of loop (P = 0.0128);Loss of loop (P = 0.0128);
MVP		0.97
MPC		0.94
ClinPred		0.99	D
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.78
gMVP		0.92

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: rs376508721; hg19: chr3-49569433;