rs139665175

Variant names:

• chr6-129143936-C-A
• rs139665175
• NM_000426.4:c.675C>A

Your query was ambiguous. Multiple possible variants found:

• chr6-129143936-C-A
• chr6-129143936-C-T

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP7

The NM_000426.4(LAMA2):​c.675C>A​(p.Ala225Ala) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,458,930 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. A225A) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: LAMA2 NM_000426.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.857
• 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: Likely_benign. The variant received -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.29).
• BP7: Synonymous conserved (PhyloP=-0.857 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMA2	NM_000426.4	c.675C>A	p.Ala225Ala	synonymous_variant	Exon 5 of 65	ENST00000421865.3	NP_000417.3
LAMA2	NM_001079823.2	c.675C>A	p.Ala225Ala	synonymous_variant	Exon 5 of 64		NP_001073291.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LAMA2	ENST00000421865.3	c.675C>A	p.Ala225Ala	synonymous_variant	Exon 5 of 65	5	NM_000426.4	ENSP00000400365.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1458930 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 725902

⚠️ 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: 33328

American (AMR) AF: 0.00 AC: 0 AN: 44584

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26056

East Asian (EAS) AF: 0.00 AC: 0 AN: 39662

South Asian (SAS) AF: 0.00 AC: 0 AN: 86180

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53394

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5758

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1109724

Other (OTH) AF: 0.00 AC: 0 AN: 60244

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.044843), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.29
CADD	Benign	1.3
DANN	Benign	0.80
PhyloP100		-0.86

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: rs139665175; hg19: chr6-129465081;