2-201727742-G-T

Variant names:

• chr2-201727742-G-T
• rs1553506293
• NM_020919.4:c.2875C>A

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_020919.4(ALS2):​c.2875C>A​(p.Leu959Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000214 in 1,399,426 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. L959P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: ALS2 NM_020919.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.56
• Publications: 0 publications found

Genes affected

ALS2 (HGNC:443): (alsin Rho guanine nucleotide exchange factor ALS2) The protein encoded by this gene contains an ATS1/RCC1-like domain, a RhoGEF domain, and a vacuolar protein sorting 9 (VPS9) domain, all of which are guanine-nucleotide exchange factors that activate members of the Ras superfamily of GTPases. The protein functions as a guanine nucleotide exchange factor for the small GTPase RAB5. The protein localizes with RAB5 on early endosomal compartments, and functions as a modulator for endosomal dynamics. Mutations in this gene result in several forms of juvenile lateral sclerosis and infantile-onset ascending spastic paralysis. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2008]

ALS2 Gene-Disease associations (from GenCC):

• ALS2-related motor neuron disease

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• amyotrophic lateral sclerosis type 2, juvenile

  Inheritance: AR Classification: STRONG Submitted by: Genomics England PanelApp
• infantile-onset ascending hereditary spastic paralysis

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Orphanet
• juvenile primary lateral sclerosis

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Orphanet
• juvenile amyotrophic lateral sclerosis

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ALS2	NM_020919.4	c.2875C>A	p.Leu959Met	missense_variant	Exon 16 of 34	ENST00000264276.11	NP_065970.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ALS2	ENST00000264276.11	c.2875C>A	p.Leu959Met	missense_variant	Exon 16 of 34	1	NM_020919.4	ENSP00000264276.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000214 AC: 3 AN: 1399426 Hom.: 0 Cov.: 33 AF XY: 0.00000290 AC XY: 2 AN XY: 690230

African (AFR) AF: 0.00 AC: 0 AN: 31602

American (AMR) AF: 0.00 AC: 0 AN: 35712

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25182

East Asian (EAS) AF: 0.00 AC: 0 AN: 35738

South Asian (SAS) AF: 0.00 AC: 0 AN: 79236

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 49278

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5694

European-Non Finnish (NFE) AF: 0.00000278 AC: 3 AN: 1078980

Other (OTH) AF: 0.00 AC: 0 AN: 58004

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Infantile-onset ascending hereditary spastic paralysis Uncertain:1

Apr 27, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces leucine with methionine at codon 959 of the ALS2 protein (p.Leu959Met). The leucine residue is highly conserved and there is a small physicochemical difference between leucine and methionine. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a ALS2-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.26
BayesDel_addAF	Uncertain	0.031	T
BayesDel_noAF	Benign	-0.19
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Benign	0.15	T
Eigen	Uncertain	0.65
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.92	D
M_CAP	Benign	0.014	T
MetaRNN	Uncertain	0.44	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Uncertain	2.4	M
PhyloP100		2.6
PrimateAI	Uncertain	0.62	T
PROVEAN	Benign	-1.1	N
REVEL	Benign	0.19
Sift	Uncertain	0.0060	D
Sift4G	Uncertain	0.011	D
Vest4		0.40
ClinPred		0.93	D
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.24
gMVP		0.48
Mutation Taster		=68/32	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs1553506293; hg19: chr2-202592465;