1-220202376-T-G

Variant names:

• chr1-220202376-T-G
• rs797045103
• NM_012414.4:c.713-2A>C

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_Moderate PM2 PP5_Moderate

The NM_012414.4(RAB3GAP2):​c.713-2A>C variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,459,672 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 Likely pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: RAB3GAP2 NM_012414.4 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.46
• Publications: 0 publications found

Genes affected

RAB3GAP2 (HGNC:17168): (RAB3 GTPase activating non-catalytic protein subunit 2) The protein encoded by this gene belongs to the RAB3 protein family, members of which are involved in regulated exocytosis of neurotransmitters and hormones. This protein forms the Rab3 GTPase-activating complex with RAB3GAP1, where it constitutes the regulatory subunit, whereas the latter functions as the catalytic subunit. This gene has the highest level of expression in the brain, consistent with it having a key role in neurodevelopment. Mutations in this gene are associated with Martsolf syndrome.[provided by RefSeq, Oct 2009]

RAB3GAP2 Gene-Disease associations (from GenCC):

• Martsolf syndrome 1

  Inheritance: AR Classification: DEFINITIVE Submitted by: G2P
• RAB18 deficiency

  Inheritance: AR Classification: DEFINITIVE Submitted by: Ambry Genetics
• Warburg micro syndrome

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• Warburg micro syndrome 2

  Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• autosomal recessive spastic paraplegia type 69

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• cataract-intellectual disability-hypogonadism syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.023672884 fraction of the gene. Cryptic splice site detected, with MaxEntScore 7, offset of 6, new splice context is: tttatctttggtcgctgcAGcat. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-220202376-T-G is Pathogenic according to our data. Variant chr1-220202376-T-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 2432913.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_012414.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	RAB3GAP2	NM_012414.4	MANE Select	c.713-2A>C		splice_acceptor intron	N/A	NP_036546.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	RAB3GAP2	ENST00000358951.7	TSL:1 MANE Select	c.713-2A>C		splice_acceptor intron	N/A	ENSP00000351832.2
	RAB3GAP2	ENST00000692972.1		c.713-2A>C		splice_acceptor intron	N/A	ENSP00000510753.1
	RAB3GAP2	ENST00000691661.1		c.725-2A>C		splice_acceptor intron	N/A	ENSP00000510185.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1459672 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 726280

⚠️ 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: 33406

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26106

East Asian (EAS) AF: 0.00 AC: 0 AN: 39604

South Asian (SAS) AF: 0.00 AC: 0 AN: 86216

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53324

Middle Eastern (MID) AF: 0.000174 AC: 1 AN: 5742

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1110236

Other (OTH) AF: 0.00 AC: 0 AN: 60318

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Warburg micro syndrome 2 Pathogenic:1

Sep 04, 2024

3billion

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The variant is observed at an extremely low frequency in the gnomAD v4.0.0 dataset (total allele frequency: <0.001%). Predicted Consequence/Location: Canonical splice site: predicted to alter splicing and result in a loss or disruption of normal protein function. Multiple pathogenic loss-of-function variants are reported downstream of the variant. In silico tools predict the variant to alter splicing and produce an abnormal transcript [SpliceAI: 0.99 (spliceogenicity >=0.2, non-spliceogenicity <0.1)]. The variant has been reported to be associated with RAB3GAP2 related disorder (ClinVar ID: VCV002432913). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline.

not provided Pathogenic:1

Mar 08, 2022

Revvity Omics, Revvity

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.33
CADD	Pathogenic	33
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Pathogenic	0.98	D
PhyloP100		7.5
GERP RS		5.5
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.77		Position offset: -8
DS_AL_spliceai		0.99		Position offset: -2

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

Other links and lift over

dbSNP: rs797045103; hg19: chr1-220375718;