chr2-201726868-T-C

Variant names:

• chr2-201726868-T-C
• rs386134184
• NM_020919.4:c.2980-2A>G

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PVS1 PM2 PP5

The NM_020919.4(ALS2):​c.2980-2A>G variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,266 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: ALS2 NM_020919.4 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic no assertion criteria provided P:2
• Conservation: PhyloP100: 7.61
• Publications: 5 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: Pathogenic. The variant received 11 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-201726868-T-C is Pathogenic according to our data. Variant chr2-201726868-T-C is described in ClinVar as Pathogenic. ClinVar VariationId is 4416.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ALS2	NM_020919.4	c.2980-2A>G		splice_acceptor_variant, intron_variant	Intron 17 of 33	ENST00000264276.11	NP_065970.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ALS2	ENST00000264276.11	c.2980-2A>G		splice_acceptor_variant, intron_variant	Intron 17 of 33	1	NM_020919.4	ENSP00000264276.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461266 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 726914

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.00 AC: 0 AN: 44666

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39692

South Asian (SAS) AF: 0.00 AC: 0 AN: 86134

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53364

Middle Eastern (MID) AF: 0.000176 AC: 1 AN: 5694

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111748

Other (OTH) AF: 0.00 AC: 0 AN: 60366

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00000000770867), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: no assertion criteria provided

Submissions by phenotype

Juvenile primary lateral sclerosis Pathogenic:2

Feb 10, 2011

GeneReviews

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: curation

- -

Jan 06, 2009

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.35
CADD	Pathogenic	33
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.99
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		7.6
GERP RS		5.5
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.83		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.29		Position offset: -8
DS_AL_spliceai		0.83		Position offset: -2

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

Other links and lift over

dbSNP: rs386134184; hg19: chr2-202591591;