14-92071009-C-CGCTGCTGCTGCTGCTG

Variant names:

• chr14-92071009-C-CGCTGCTGCTGCTGCTG
• rs763461489
• NM_004993.6:c.916_917insCAGCAGCAGCAGCAGC

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 0P and 0B.

The NM_004993.6(ATXN3):​c.916_917insCAGCAGCAGCAGCAGC​(p.Gly306AlafsTer17) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type INS_BIG, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Uncertain significance (no stars). Synonymous variant affecting the same amino acid position (i.e. G306G) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 22)
• Consequence: ATXN3 NM_004993.6 frameshift
• Clinical Significance: Uncertain significance no assertion criteria provided U:1
• Conservation: PhyloP100: -0.802
• Publications: 0 publications found

Genes affected

ATXN3 (HGNC:7106): (ataxin 3) Machado-Joseph disease, also known as spinocerebellar ataxia-3, is an autosomal dominant neurologic disorder. The protein encoded by this gene contains (CAG)n repeats in the coding region, and the expansion of these repeats from the normal 12-44 to 52-86 is one cause of Machado-Joseph disease. There is a negative correlation between the age of onset and CAG repeat numbers. Alternatively spliced transcript variants encoding different isoforms have been described for this gene. [provided by RefSeq, Jul 2016]

ATXN3 Gene-Disease associations (from GenCC):

• Machado-Joseph disease

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae)
• Machado-Joseph disease type 1

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Machado-Joseph disease type 2

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Machado-Joseph disease type 3

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000303901 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ATXN3	NM_004993.6	c.916_917insCAGCAGCAGCAGCAGC	p.Gly306AlafsTer17	frameshift_variant	Exon 10 of 11	ENST00000644486.2	NP_004984.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ATXN3	ENST00000644486.2	c.916_917insCAGCAGCAGCAGCAGC	p.Gly306AlafsTer17	frameshift_variant	Exon 10 of 11		NM_004993.6	ENSP00000496695.1

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 50

GnomAD4 genome Cov.: 22

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: no assertion criteria provided

Submissions by phenotype

not provided Uncertain:1

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Department of Pathology and Laboratory Medicine, Sinai Health System

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.80

Splicing

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

Other links and lift over

dbSNP: rs763461489; hg19: chr14-92537353;