16-48362067-C-CA

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_003031.4(SIAH1):c.361_362insT(p.Cys121LeufsTer2) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: SIAH1 NM_003031.4 frameshift
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.32

Genes affected

SIAH1 (HGNC:10857): (siah E3 ubiquitin protein ligase 1) This gene encodes a protein that is a member of the seven in absentia homolog (SIAH) family. The protein is an E3 ligase and is involved in ubiquitination and proteasome-mediated degradation of specific proteins. The activity of this ubiquitin ligase has been implicated in the development of certain forms of Parkinson's disease, the regulation of the cellular response to hypoxia and induction of apoptosis. Alternative splicing results in several additional transcript variants, some encoding different isoforms and others that have not been fully characterized. [provided by RefSeq, Jul 2008]

LONP2 (HGNC:20598): (lon peptidase 2, peroxisomal) In human, peroxisomes function primarily to catalyze fatty acid beta-oxidation and, as a by-product, produce hydrogen peroxide and superoxide. The protein encoded by this gene is an ATP-dependent protease that likely plays a role in maintaining overall peroxisome homeostasis as well as proteolytically degrading peroxisomal proteins damaged by oxidation. The protein has an N-terminal Lon N substrate recognition domain, an ATPase domain, a proteolytic domain, and, in some isoforms, a C-terminal peroxisome targeting sequence. Alternative splicing results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, Jan 2017]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 12 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 16-48362067-C-CA is Pathogenic according to our data. Variant chr16-48362067-C-CA is described in ClinVar as [Likely_pathogenic]. Clinvar id is 3235937.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SIAH1	NM_003031.4	c.361_362insT	p.Cys121LeufsTer2	frameshift_variant	2/2	ENST00000394725.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SIAH1	ENST00000394725.3	c.361_362insT	p.Cys121LeufsTer2	frameshift_variant	2/2	1	NM_003031.4	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Buratti-Harel syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

New York Genome Center

Nov 23, 2022

The c.361dup variant in SIAH1 has not previously been reported in the literature or public variant repositories (ClinVar and LOVD), and it is absent from population databases (gnomAD v2.1.1 and v3.1.2, TOPMed Freeze 8, All of Us), suggesting it is not a common benign variant in the populations represented in those databases; however, there are other truncating variant carriers in exon 2 in gnomAD v2.1.1 dataset. The c.361dup variant in SIAH1 is located in exon 2 of this 2-exon gene, and is predicted to result in loss of >10% of this 282-amino acid long protein (p.Cys121LeufsTer2). Personal communication with an external expert provided previously unpublished clinical information of two individuals with neurodevelopmental disorders who were found to harbor de novo and not-maternally-inherited, respectively, truncating variants in exon 2. Based on recent evidence this de novo heterozygous c.361dup p.(Cys121LeufsTer2) variant identified in SIAH1 is classified here as Likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr16-48395978;