6-129454287-A-T

Variant names:

• chr6-129454287-A-T
• rs886038293
• NM_000426.4:c.6706A>T

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP3_Moderate

The NM_000426.4(LAMA2):​c.6706A>T​(p.Arg2236*) variant causes a stop gained, splice region change. The variant allele was found at a frequency of 0.000000686 in 1,457,874 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. R2236R) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: LAMA2 NM_000426.4 stop_gained, splice_region
• Scores: Splicing: ADA: 0.9998
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 5.30
• 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: Labcorp Genetics (formerly Invitae), Orphanet, G2P, Myriad Women’s Health
• 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)

ENSG00000226149 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• 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.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000426.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	LAMA2	NM_000426.4	MANE Select	c.6706A>T	p.Arg2236*	stop_gained splice_region	Exon 47 of 65	NP_000417.3
	LAMA2	NM_001079823.2		c.6706A>T	p.Arg2236*	stop_gained splice_region	Exon 47 of 64	NP_001073291.2	A0A087WYF1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	LAMA2	ENST00000421865.3	TSL:5 MANE Select	c.6706A>T	p.Arg2236*	stop_gained splice_region	Exon 47 of 65	ENSP00000400365.2	P24043
	LAMA2	ENST00000618192.5	TSL:5	c.6970A>T	p.Arg2324*	stop_gained splice_region	Exon 48 of 66	ENSP00000480802.2	A0A087WX80
	LAMA2	ENST00000617695.5	TSL:5	c.6706A>T	p.Arg2236*	stop_gained splice_region	Exon 47 of 64	ENSP00000481744.2	A0A087WYF1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000400 AC: 1 AN: 250254 AF XY: 0.00000739

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.86e-7 AC: 1 AN: 1457874 Hom.: 0 Cov.: 28 AF XY: 0.00000138 AC XY: 1 AN XY: 725450

African (AFR) AF: 0.00 AC: 0 AN: 33376

American (AMR) AF: 0.00 AC: 0 AN: 44614

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26066

East Asian (EAS) AF: 0.00 AC: 0 AN: 39576

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86120

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53334

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5752

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1108820

Other (OTH) AF: 0.00 AC: 0 AN: 60216

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	56
DANN	Uncertain	1.0
Eigen	Pathogenic	0.95
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Uncertain	0.89	D
PhyloP100		5.3
Vest4		0.95
GERP RS		5.8
Mutation Taster		=3/197	disease causing (fs/PTC)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.98
SpliceAI score (max)		0.58		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.58		Position offset: -20
DS_DL_spliceai		0.29		Position offset: 1

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

Other links and lift over

dbSNP: rs886038293; hg19: chr6-129775432;