14-92071010-CCTGCTGCTGCTG-CCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTG

Variant names:

• chr14-92071010-C-CCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTG
• rs193922928
• NM_004993.6:c.915_916insCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAG

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP3

The NM_004993.6(ATXN3):​c.915_916insCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAG​(p.Gln305_Gly306insGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGln) variant causes a conservative inframe insertion change involving the alteration of a non-conserved nucleotide. 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. There is a variant allele frequency bias in the population database for this variant (GnomAd4), which may indicate mosaicism or somatic mutations in the reference population data. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: 𝑓 0.0044 (41 hom., cov: 20)
  • Exomes 𝑓: 0.00023 (2 hom.)
  • Failed GnomAD Quality Control
• Consequence: ATXN3 NM_004993.6 conservative_inframe_insertion
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.168
• Publications: 1 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, Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine
• 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: Likely_benign. The variant received -1 ACMG points.

• BP3: Nonframeshift variant in repetitive region in NM_004993.6

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004993.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ATXN3	NM_004993.6	MANE Select	c.915_916insCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAG	p.Gln305_Gly306insGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGln	conservative_inframe_insertion	Exon 10 of 11	NP_004984.2
	ATXN3	NM_001127696.2		c.870_871insCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAG	p.Gln290_Gly291insGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGln	conservative_inframe_insertion	Exon 9 of 10	NP_001121168.1	P54252-4
	ATXN3	NM_001127697.3		c.762_763insCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAG	p.Gln254_Gly255insGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGln	conservative_inframe_insertion	Exon 8 of 9	NP_001121169.2	A0A0A0MS38

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ATXN3	ENST00000644486.2	MANE Select	c.915_916insCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAG	p.Gln305_Gly306insGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGln	conservative_inframe_insertion	Exon 10 of 11	ENSP00000496695.1	P54252-2
	ATXN3	ENST00000532032.5	TSL:1	c.915_916insCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAG	p.Gln305_Gly306insGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGln	conservative_inframe_insertion	Exon 10 of 10	ENSP00000437157.1	P54252-1
	ATXN3	ENST00000503767.5	TSL:1	c.870_871insCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAG	p.Gln290_Gly291insGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGln	conservative_inframe_insertion	Exon 9 of 10	ENSP00000426697.1	P54252-4

Frequencies

GnomAD3 genomes AF: 0.00442 AC: 629 AN: 142304 Hom.: 40 Cov.: 20

Gnomad AFR AF: 0.0150

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00375

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000464

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00658

Gnomad NFE AF: 0.000376

Gnomad OTH AF: 0.00309

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.000229 AC: 301 AN: 1313936 Hom.: 2 Cov.: 92 AF XY: 0.000184 AC XY: 121 AN XY: 656994

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00631 AC: 172 AN: 27278

American (AMR) AF: 0.000371 AC: 15 AN: 40450

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 24398

East Asian (EAS) AF: 0.00 AC: 0 AN: 37448

South Asian (SAS) AF: 0.000126 AC: 10 AN: 79458

European-Finnish (FIN) AF: 0.0000409 AC: 2 AN: 48910

Middle Eastern (MID) AF: 0.000194 AC: 1 AN: 5142

European-Non Finnish (NFE) AF: 0.0000693 AC: 69 AN: 995806

Other (OTH) AF: 0.000581 AC: 32 AN: 55046

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.00442 AC: 629 AN: 142414 Hom.: 41 Cov.: 20 AF XY: 0.00425 AC XY: 294 AN XY: 69178

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.0149 AC: 541 AN: 36230

American (AMR) AF: 0.00368 AC: 53 AN: 14408

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3412

East Asian (EAS) AF: 0.00 AC: 0 AN: 4634

South Asian (SAS) AF: 0.000464 AC: 2 AN: 4310

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 9884

Middle Eastern (MID) AF: 0.00709 AC: 2 AN: 282

European-Non Finnish (NFE) AF: 0.000376 AC: 25 AN: 66412

Other (OTH) AF: 0.00306 AC: 6 AN: 1962

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.17
Mutation Taster		=78/22	polymorphism

Splicing

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

Other links and lift over

dbSNP: rs193922928; hg19: chr14-92537354;