rs761823344

Variant names:

• chr6-129393042-C-G
• rs761823344
• NM_000426.4:c.5235-3C>G

Your query was ambiguous. Multiple possible variants found:

• chr6-129393042-C-G
• chr6-129393042-C-T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_000426.4(LAMA2):​c.5235-3C>G variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,158 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: LAMA2 NM_000426.4 splice_region, intron
• Scores: Splicing: ADA: 0.9987
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.536
• Publications: 0 publications found

Genes affected

LAMA2 (HGNC:6482): (laminin subunit alpha 2) Laminin, an extracellular protein, is a major component of the basement membrane. It is thought to mediate the attachment, migration, and organization of cells into tissues during embryonic development by interacting with other extracellular matrix components. It is composed of three subunits, alpha, beta, and gamma, which are bound to each other by disulfide bonds into a cross-shaped molecule. This gene encodes the alpha 2 chain, which constitutes one of the subunits of laminin 2 (merosin) and laminin 4 (s-merosin). Mutations in this gene have been identified as the cause of congenital merosin-deficient muscular dystrophy. Two transcript variants encoding different proteins have been found for this gene. [provided by RefSeq, Jul 2008]

LAMA2 Gene-Disease associations (from GenCC):

• congenital merosin-deficient muscular dystrophy 1A

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), Myriad Women’s Health, G2P
• LAMA2-related muscular dystrophy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• muscular dystrophy, limb-girdle, autosomal recessive 23

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMA2	NM_000426.4	c.5235-3C>G		splice_region_variant, intron_variant	Intron 36 of 64	ENST00000421865.3	NP_000417.3
LAMA2	NM_001079823.2	c.5235-3C>G		splice_region_variant, intron_variant	Intron 36 of 63		NP_001073291.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LAMA2	ENST00000421865.3	c.5235-3C>G		splice_region_variant, intron_variant	Intron 36 of 64	5	NM_000426.4	ENSP00000400365.2
LAMA2	ENST00000618192.5	c.5499-3C>G		splice_region_variant, intron_variant	Intron 37 of 65	5		ENSP00000480802.2
LAMA2	ENST00000617695.5	c.5235-3C>G		splice_region_variant, intron_variant	Intron 36 of 63	5		ENSP00000481744.2
LAMA2	ENST00000687590.1	n.1655-3C>G		splice_region_variant, intron_variant	Intron 4 of 4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460158 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 726492

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33452

American (AMR) AF: 0.00 AC: 0 AN: 44696

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26128

East Asian (EAS) AF: 0.00 AC: 0 AN: 39688

South Asian (SAS) AF: 0.00 AC: 0 AN: 86242

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52564

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5722

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111304

Other (OTH) AF: 0.00 AC: 0 AN: 60362

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

LAMA2-related muscular dystrophy Uncertain:1

Oct 23, 2016

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 36 of the LAMA2 gene. It does not directly change the encoded amino acid sequence of the LAMA2 protein. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a LAMA2-related disease. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may alter RNA splicing, but this prediction has not been confirmed by published transcriptional studies. In summary, this is a novel intronic change with uncertain impact on splicing. It has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.64
CADD	Benign	22
DANN	Benign	0.53
PhyloP100		0.54

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.77
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.99		Position offset: 1
DS_AL_spliceai		0.97		Position offset: 3

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

Other links and lift over

dbSNP: rs761823344; hg19: chr6-129714187;