Genetic Variant NM_005413.4:c.20delT (chr2-44942123-CT-C) – ACMG Classification: Pathogenic (18 pts)

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_005413.4(SIX3):c.20delT(p.Leu7GlnfsTer244) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: not found (cov: 31)

Exomes 𝑓: 0.0000055 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

SIX3
NM_005413.4 frameshift

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2

Conservation

PhyloP100: 6.70

Variant links:

Genes affected

SIX3 (HGNC:10889): (SIX homeobox 3) This gene encodes a member of the sine oculis homeobox transcription factor family. The encoded protein plays a role in eye development. Mutations in this gene have been associated with holoprosencephaly type 2. [provided by RefSeq, Oct 2009]

SIX3 links:

SIX3-AS1 (HGNC:40532): (SIX3 antisense RNA 1)

SIX3-AS1 links:

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 34 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 2-44942123-CT-C is Pathogenic according to our data. Variant chr2-44942123-CT-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2729808.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SIX3	NM_005413.4 link	c.20delT	p.Leu7GlnfsTer244	frameshift_variant	Exon 1 of 2	ENST00000260653.5	NP_005404.1	O95343
SIX3-AS1	NR_103786.1 link	n.-246delA		upstream_gene_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SIX3	ENST00000260653.5 link	c.20delT	p.Leu7GlnfsTer244	frameshift_variant	Exon 1 of 2	1	NM_005413.4	ENSP00000260653.3		O95343
SIX3-AS1	ENST00000419364.3 link	n.-208delA		upstream_gene_variant		2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

0.00000554

AC:

AN:

1444074

Hom.:

Cov.:

AF XY:

0.00000556

AC XY:

AN XY:

718858

show subpopulations

Gnomad4 AFR exome

AF:

0.0000300

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000631

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

Bravo

AF:

0.0000113

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Holoprosencephaly 2

Pathogenic:1

Jul 17, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. This variant has not been reported in the literature in individuals affected with SIX3-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Leu7Glnfs*244) in the SIX3 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in SIX3 are known to be pathogenic (PMID: 18791198). -

not provided

Pathogenic:1

Apr 19, 2024

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift variant predicted to result in abnormal protein length as the last 326 amino acids are replaced with 243 different amino acids, and other similar variants have been reported in HGMD; Not observed at significant frequency in large population cohorts (gnomAD); Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over