rs1553687898

Positions:

• chr3-69119576-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP3_Strong PP5

The NM_198271.5(LMOD3):​c.779T>C​(p.Leu260Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 13/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. L260L) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 31)
• Consequence: LMOD3 NM_198271.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 9.32

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 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.963
• PP5: Variant 3-69119576-A-G is Pathogenic according to our data. Variant chr3-69119576-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 432042.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
LMOD3	NM_198271.5	c.779T>C	p.Leu260Pro	missense_variant	2/3	ENST00000420581.7
LMOD3	NM_001304418.3	c.779T>C	p.Leu260Pro	missense_variant	3/4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
LMOD3	ENST00000420581.7	c.779T>C	p.Leu260Pro	missense_variant	2/3	1	NM_198271.5	P1
LMOD3	ENST00000475434.1	c.779T>C	p.Leu260Pro	missense_variant	3/4	5		P1
LMOD3	ENST00000489031.5	c.779T>C	p.Leu260Pro	missense_variant	3/4	2		P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 31

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Dec 10, 2015

The L260P variant in the LMOD3 gene has not been reported previously as a pathogenic variant, nor as a benign variant, to our knowledge. The L260P variant was not observed in approximately 6000 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The L260P variant is a semi-conservative amino acid substitution, which may impact secondary protein structure as these residues differ in some properties. This substitution occurs at a position that is conserved across species and in silico analysis predicts this variant is probably damaging to the protein structure/function. The L260P variant is a strong candidate for a pathogenic variant, however the possibility it may be a rare benign variant cannot be excluded. -

Nemaline myopathy 10 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 10, 2017

This sequence change replaces leucine with proline at codon 260 of the LMOD3 protein (p.Leu260Pro). The leucine residue is highly conserved and there is a moderate physicochemical difference between leucine and proline. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with LMOD3-related disease. 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. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.18
CADD	Pathogenic	28
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.36	T;T;T
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.91	.;.;D
M_CAP	Uncertain	0.11	D
MetaRNN	Pathogenic	0.96	D;D;D
MetaSVM	Benign	-0.33	T
MutationAssessor	Pathogenic	3.4	M;M;M
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-5.1	D;D;D
REVEL	Pathogenic	0.74
Sift	Pathogenic	0.0	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		1.0	D;D;D
Vest4		0.98
MutPred		0.88		Loss of stability (P = 0.0189);Loss of stability (P = 0.0189);Loss of stability (P = 0.0189);
MVP		0.76
MPC		0.19
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.91
gMVP		0.92

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: rs1553687898; hg19: chr3-69168727;