rs778824655

chr3-69119325-G-A

Variant summary

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

The NM_198271.5(LMOD3):c.1030C>T(p.Arg344Trp) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,698 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R344Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: LMOD3 NM_198271.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.53

Genes affected

LMOD3 (HGNC:6649): (leiomodin 3) The protein encoded by this gene is a member of the leiomodin family of proteins. This protein contains three actin-binding domains, a tropomyosin domain, a leucine-rich repeat domain, and a Wiskott-Aldrich syndrome protein homology 2 domain (WH2). Localization of this protein to the pointed ends of thin filaments has been observed, and there is evidence that this protein acts as a catalyst of actin nucleation, and is important to the organization of sarcomeric thin filaments in skeletal muscles. Mutations in this gene have been associated as one cause of Nemaline myopathy, as other genes have also been linked to this disorder. Nemaline myopathy is a disorder characterized by nonprogressive generalized muscle weakness and protein inclusions (nemaline bodies) in skeletal myofibers. Patients with mutations in this gene often present with a severe congenital form of the disorder. [provided by RefSeq, Jan 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, 0.951

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
LMOD3	NM_198271.5	c.1030C>T	p.Arg344Trp	missense_variant	2/3	ENST00000420581.7
LMOD3	NM_001304418.3	c.1030C>T	p.Arg344Trp	missense_variant	3/4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
LMOD3	ENST00000420581.7	c.1030C>T	p.Arg344Trp	missense_variant	2/3	1	NM_198271.5	P1
LMOD3	ENST00000475434.1	c.1030C>T	p.Arg344Trp	missense_variant	3/4	5		P1
LMOD3	ENST00000489031.5	c.1030C>T	p.Arg344Trp	missense_variant	3/4	2		P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD3 exomes AF: 0.00000402 AC: 1 AN: 248812 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 134940

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000888

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461698 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727126

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

Alfa AF: 0.0000329 Hom.: 0

Bravo AF: 0.00000378

ExAC AF: 0.00000827 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Nemaline myopathy 10 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 13, 2018

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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with LMOD3-related disease. ClinVar contains an entry for this variant (Variation ID: 475294). This variant is present in population databases (rs778824655, ExAC 0.001%). This sequence change replaces arginine with tryptophan at codon 344 of the LMOD3 protein (p.Arg344Trp). The arginine residue is highly conserved and there is a moderate physicochemical difference between arginine and tryptophan. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.83
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.41
Cadd	Pathogenic	30
Dann	Pathogenic	1.0
DEOGEN2	Benign	0.15	T;T;T
Eigen	Pathogenic	0.82
Eigen_PC	Pathogenic	0.80
FATHMM_MKL	Uncertain	0.93	D
M_CAP	Pathogenic	0.31	D
MetaRNN	Pathogenic	0.95	D;D;D
MetaSVM	Pathogenic	0.94	D
MutationAssessor	Uncertain	2.4	M;M;M
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-7.7	D;D;D
REVEL	Pathogenic	0.87
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0	D;D;D
Vest4		0.95
MVP		0.97
MPC		0.17
ClinPred		1.0	D
GERP RS		5.8
Varity_R		0.86
gMVP		0.75

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: rs778824655; hg19: chr3-69168476; COSMIC: COSV70456816;