2-29297035-C-A

Position:

• chr2-29297035-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_004304.5(ALK):​c.1670G>T​(p.Arg557Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,860 control chromosomes in the GnomAD database, with no homozygous occurrence. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ALK NM_004304.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.515

Genes affected

ALK (HGNC:427): (ALK receptor tyrosine kinase) This gene encodes a receptor tyrosine kinase, which belongs to the insulin receptor superfamily. This protein comprises an extracellular domain, an hydrophobic stretch corresponding to a single pass transmembrane region, and an intracellular kinase domain. It plays an important role in the development of the brain and exerts its effects on specific neurons in the nervous system. This gene has been found to be rearranged, mutated, or amplified in a series of tumours including anaplastic large cell lymphomas, neuroblastoma, and non-small cell lung cancer. The chromosomal rearrangements are the most common genetic alterations in this gene, which result in creation of multiple fusion genes in tumourigenesis, including ALK (chromosome 2)/EML4 (chromosome 2), ALK/RANBP2 (chromosome 2), ALK/ATIC (chromosome 2), ALK/TFG (chromosome 3), ALK/NPM1 (chromosome 5), ALK/SQSTM1 (chromosome 5), ALK/KIF5B (chromosome 10), ALK/CLTC (chromosome 17), ALK/TPM4 (chromosome 19), and ALK/MSN (chromosome X).[provided by RefSeq, Jan 2011]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ALK	NM_004304.5	c.1670G>T	p.Arg557Leu	missense_variant	9/29	ENST00000389048.8	NP_004295.2
ALK	XR_001738688.3	n.2597G>T		non_coding_transcript_exon_variant	9/18

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ALK	ENST00000389048.8	c.1670G>T	p.Arg557Leu	missense_variant	9/29	1	NM_004304.5	ENSP00000373700	P1
ALK	ENST00000618119.4	c.539G>T	p.Arg180Leu	missense_variant	8/28	5		ENSP00000482733
ALK	ENST00000498037.1	n.225G>T		non_coding_transcript_exon_variant	3/5	4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461860 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727232

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: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neuroblastoma, susceptibility to, 3 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 22, 2019

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 are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C35"). This variant has not been reported in the literature in individuals with ALK-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces arginine with leucine at codon 557 of the ALK protein (p.Arg557Leu). The arginine residue is moderately conserved and there is a moderate physicochemical difference between arginine and leucine. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

May 13, 2022

The p.R557L variant (also known as c.1670G>T), located in coding exon 9 of the ALK gene, results from a G to T substitution at nucleotide position 1670. The arginine at codon 557 is replaced by leucine, an amino acid with dissimilar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Benign	-0.17	T
BayesDel_noAF	Benign	-0.48
CADD	Benign	15
DANN	Uncertain	0.99
DEOGEN2	Benign	0.091	T;.
Eigen	Benign	-0.14
Eigen_PC	Benign	-0.085
FATHMM_MKL	Benign	0.62	D
LIST_S2	Benign	0.72	T;T
M_CAP	Benign	0.026	D
MetaRNN	Uncertain	0.46	T;T
MetaSVM	Benign	-0.57	T
MutationAssessor	Benign	2.0	M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Benign	0.23	T
PROVEAN	Benign	-1.1	N;.
REVEL	Benign	0.11
Sift	Benign	0.48	T;.
Sift4G	Benign	0.55	T;T
Polyphen		0.74	P;.
Vest4		0.42
MutPred		0.72		Loss of MoRF binding (P = 0.0085);.;
MVP		0.55
MPC		0.22
ClinPred		0.78	D
GERP RS		2.0
Varity_R		0.16
gMVP		0.75

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs200468507; hg19: chr2-29519901;