Genetic Variant LAMA1:p.Cys739Phe (chr18-7032124-C-A) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2PP3_Strong

The NM_005559.4(LAMA1):c.2216G>T(p.Cys739Phe) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,870 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C739Y) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

LAMA1
NM_005559.4 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 7.57

Publications

0 publications found

Variant links:

Genes affected

LAMA1 (HGNC:6481): (laminin subunit alpha 1) This gene encodes one of the alpha 1 subunits of laminin. The laminins are a family of extracellular matrix glycoproteins that have a heterotrimeric structure consisting of an alpha, beta and gamma chain. These proteins make up a major component of the basement membrane and have been implicated in a wide variety of biological processes including cell adhesion, differentiation, migration, signaling, neurite outgrowth and metastasis. Mutations in this gene may be associated with Poretti-Boltshauser syndrome. [provided by RefSeq, Sep 2014]

LAMA1 Gene-Disease associations (from GenCC):

ataxia - intellectual disability - oculomotor apraxia - cerebellar cysts syndrome
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Labcorp Genetics (formerly Invitae)

LAMA1 links:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.991

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LAMA1	NM_005559.4 link	c.2216G>T	p.Cys739Phe	missense_variant	Exon 16 of 63	ENST00000389658.4	NP_005550.2	P25391

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LAMA1	ENST00000389658.4 link	c.2216G>T	p.Cys739Phe	missense_variant	Exon 16 of 63	1	NM_005559.4	ENSP00000374309.3		P25391
LAMA1	ENST00000579014.5 link	n.3231G>T		non_coding_transcript_exon_variant	Exon 15 of 62	2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461870

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727238

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1112000

Other (OTH)

AF:

0.00

AC:

AN:

60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.97

BayesDel_addAF

Pathogenic

0.39

BayesDel_noAF

Pathogenic

0.33

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.65

Eigen

Pathogenic

0.95

Eigen_PC

Pathogenic

0.86

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.92

M_CAP

Uncertain

0.19

MetaRNN

Pathogenic

0.99

MetaSVM

Uncertain

0.57

MutationAssessor

Pathogenic

3.6

PhyloP100

7.6

PrimateAI

Uncertain

0.64

PROVEAN

Pathogenic

-9.3

REVEL

Pathogenic

0.79

Sift

Pathogenic

0.0

Sift4G

Uncertain

0.0050

Polyphen

1.0

Vest4

0.96

MutPred

0.93

Loss of catalytic residue at C742 (P = 0.4357);

MVP

0.87

MPC

0.65

ClinPred

1.0

GERP RS

5.4

Varity_R

0.96

gMVP

0.94

Mutation Taster

=18/82

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over