22-20993967-G-T

Position:

• chr22-20993967-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM5 PP3_Moderate

The NM_006767.4(LZTR1):​c.1397G>T​(p.Arg466Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000411 in 1,460,352 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R466W) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: LZTR1 NM_006767.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:3
• Conservation: PhyloP100: 7.76

Genes affected

LZTR1 (HGNC:6742): (leucine zipper like post translational regulator 1) This gene encodes a member of the BTB-kelch superfamily. Initially described as a putative transcriptional regulator based on weak homology to members of the basic leucine zipper-like family, the encoded protein subsequently has been shown to localize exclusively to the Golgi network where it may help stabilize the Gogli complex. Deletion of this gene may be associated with DiGeorge syndrome. [provided by RefSeq, Jul 2008]

ENSG00000285314 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM5: Other missense variant is known to change same aminoacid residue: Variant chr22-20993966-C-T is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.92

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
LZTR1	NM_006767.4	c.1397G>T	p.Arg466Leu	missense_variant	13/21	ENST00000646124.2	NP_006758.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
LZTR1	ENST00000646124.2	c.1397G>T	p.Arg466Leu	missense_variant	13/21		NM_006767.4	ENSP00000496779.1

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1460352 Hom.: 0 Cov.: 34 AF XY: 0.00000551 AC XY: 4 AN XY: 726434

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: 0.00000540

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 34

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Mar 05, 2020	Not observed in large population cohorts (Lek 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jul 16, 2022	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. ClinVar contains an entry for this variant (Variation ID: 1312561). This variant has not been reported in the literature in individuals affected with LZTR1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 466 of the LZTR1 protein (p.Arg466Leu). -

Hereditary cancer-predisposing syndrome;CN230736:Cardiovascular phenotype Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 16, 2023

The p.R466L variant (also known as c.1397G>T), located in coding exon 13 of the LZTR1 gene, results from a G to T substitution at nucleotide position 1397. The arginine at codon 466 is replaced by leucine, an amino acid with dissimilar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the supporting evidence, this variant is likely pathogenic for an increased risk of LZTR1-related schwannomatosis (SWN) and would be expected to cause autosomal recessive Noonan syndrome when present along with a second pathogenic variant on the other allele. -

LZTR1-related schwannomatosis Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genetics and Molecular Pathology, SA Pathology

Jun 07, 2023

The LZTR1 c.1397G>T variant is classified as a VUS (PM2, PP3, PM5) The LZTR1 c.1397G>T variant is a single nucleotide change in exon 13/21 of the LZTR1 gene, which is predicted to change the amino acid arginine at position 466 in the protein to leucine. This variant is absent from population databases (PM2). Computational predictions support a deleterious effect on the gene or gene product (PP3). This variant is a novel missense change at an amino acid residue where a different missense change has been seen before as both heterozygous and compound heterozygous in association with schwannomatosis and Noonan syndrome; p.Arg466Gln (PMID: 24362817, 31130284, 31219622) (PM5). A third missense change at this codon has also been reported but its clinical significance is uncertain; p.Arg466Trp (PMID: 31475041, 29409008, 29384852). Steklov et al. 2018 (PMID: 30442762) reported both the p.Arg466Gln and p.Arg466Trp variants in a total of 5 individuals with schwannomatosis. They demonstrated reduced binding of both LZTR1 mutated proteins to CUL3 using immunoblotting. The p.(Arg466Leu) variant has been reported as Uncertain significance by other diagnostic laboratories (ClinVar Variation ID: 1312561). It has not been reported in dbSNP, HGMD 2023.1 or the scientific literature to date. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.28
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.73	D;D
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	0.97	.;D
M_CAP	Pathogenic	0.81	D
MetaRNN	Pathogenic	0.92	D;D
MetaSVM	Uncertain	0.13	D
MutationAssessor	Uncertain	2.7	M;M
PrimateAI	Uncertain	0.67	T
PROVEAN	Pathogenic	-6.0	D;.
REVEL	Pathogenic	0.85
Sift	Uncertain	0.0040	D;.
Sift4G	Uncertain	0.013	D;.
Polyphen		1.0	D;D
Vest4		0.95
MutPred		0.55		Loss of disorder (P = 0.0713);Loss of disorder (P = 0.0713);
MVP		0.83
MPC		0.39
ClinPred		1.0	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.64
gMVP		0.89

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr22-21348256;