2-196433459-C-T

Variant names:

• chr2-196433459-C-T
• rs755596278
• NM_001348768.2:c.-35-1G>A

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PVS1_Moderate BS1_Supporting BS2

The NM_001348768.2(HECW2):​c.-35-1G>A variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.00000975 in 1,435,750 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 Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000098 (0 hom.)
• Consequence: HECW2 NM_001348768.2 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.68

Genes affected

HECW2 (HGNC:29853): (HECT, C2 and WW domain containing E3 ubiquitin protein ligase 2) This gene encodes a member of a family of E3 ubiquitin ligases which plays an important role in the proliferation, migration and differentiation of neural crest cells as a regulator of glial cell line-derived neurotrophic factor (GDNF)/Ret signaling. This gene also plays an important role in angiogenesis through stabilization of endothelial cell-to-cell junctions as a regulator of angiomotin-like 1 stability. The encoded protein contains an N-terminal calcium/lipid-binding (C2) domain involved in membrane targeting, two-four WW domains responsible for cellular localization and substrate recognition, and a C-terminal homologous with E6-associated protein C-terminus (HECT) catalytic domain. Naturally occurring mutations in this gene are associated with neurodevelopmental delay, hypotonia, and epilepsy. The decreased expression of this gene in the aganglionic colon is associated with Hirschsprung's disease. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2017]

LOC105373822 (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -3 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.06929434 fraction of the gene. Cryptic splice site detected, with MaxEntScore 6.9, offset of 8, new splice context is: tgtctcttgcaactttgtAGgca. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• BS1: Variant frequency is greater than expected in population sas. gnomad4_exome allele frequency = 0.00000975 (14/1435750) while in subpopulation SAS AF= 0.000169 (14/82604). AF 95% confidence interval is 0.000102. There are 0 homozygotes in gnomad4_exome. There are 9 alleles in male gnomad4_exome subpopulation. Median coverage is 29. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAdExome4 at 14 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HECW2	NM_001348768.2	c.-35-1G>A		splice_acceptor_variant, intron_variant	Intron 1 of 28	ENST00000644978.2	NP_001335697.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HECW2	ENST00000644978.2	c.-35-1G>A		splice_acceptor_variant, intron_variant	Intron 1 of 28		NM_001348768.2	ENSP00000495418.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000261 AC: 6 AN: 229964 Hom.: 0 AF XY: 0.0000403 AC XY: 5 AN XY: 124166

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.000228

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000975 AC: 14 AN: 1435750 Hom.: 0 Cov.: 29 AF XY: 0.0000126 AC XY: 9 AN XY: 712616

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: 0.000169

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Neurodevelopmental disorder with hypotonia, seizures, and absent language Uncertain:1

Aug 07, 2018

Genomic Research Center, Shahid Beheshti University of Medical Sciences

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Pathogenic	0.33
CADD	Pathogenic	35
DANN	Uncertain	1.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.98		Position offset: -9
DS_AL_spliceai		1.0		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs755596278; hg19: chr2-197298183;