rs1555444885

Variant names:

• chr15-75400810-G-A
• rs1555444885
• NM_001145358.2:c.1657C>T

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_001145358.2(SIN3A):​c.1657C>T​(p.Arg553*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SIN3A NM_001145358.2 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 0.965
• Publications: 0 publications found

Genes affected

SIN3A (HGNC:19353): (SIN3 transcription regulator family member A) The protein encoded by this gene is a transcriptional regulatory protein. It contains paired amphipathic helix (PAH) domains, which are important for protein-protein interactions and may mediate repression by the Mad-Max complex. [provided by RefSeq, Jul 2008]

SIN3A Gene-Disease associations (from GenCC):

• SIN3A-related intellectual disability syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Illumina, G2P, ClinGen
• chromosome 15q24 deletion syndrome

  Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• SIN3A-related intellectual disability syndrome due to a point mutation

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• congenital diaphragmatic hernia

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 15-75400810-G-A is Pathogenic according to our data. Variant chr15-75400810-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 520687.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
SIN3A	NM_001145358.2	c.1657C>T	p.Arg553*	stop_gained	Exon 11 of 21	ENST00000394947.8	NP_001138830.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SIN3A	ENST00000394947.8	c.1657C>T	p.Arg553*	stop_gained	Exon 11 of 21	1	NM_001145358.2	ENSP00000378402.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Jan 29, 2020

Clinical Genetics and Genomics, Karolinska University Hospital

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jun 29, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Identified in an individual with a neurodevelopmental disorder, but segregation and detailed clinical information was not provided (Wang et al., 2020); Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 33004838) -

SIN3A-related intellectual disability syndrome Pathogenic:1

Oct 16, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: SIN3A c.1657C>T (p.Arg553X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant was absent in 251464 control chromosomes. c.1657C>T has been reported in the literature in individuals affected with Witteveen-Kolk syndrome (e.g. Jacobson_2022). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 35144002). Two submitters have cited clinical-significance assessments for this variant to ClinVar after 2014, classifying the variant as pathogenic (n=1) or likely pathogenic (n=1). Based on the evidence outlined above, the variant was classified as pathogenic. -

Inborn genetic diseases Pathogenic:1

Dec 05, 2016

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	36
DANN	Uncertain	1.0
Eigen	Uncertain	0.63
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Uncertain	0.89	D
PhyloP100		0.96
Vest4		0.91
GERP RS		3.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=0/200	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs1555444885; hg19: chr15-75693151; COSMIC: COSV100845253;