14-92071010-CCTGCTGCTGCTG-CCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTG

Variant names:

• chr14-92071010-C-CCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTGCTG
• rs193922928
• NM_004993.6:c.915_916insCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAG

Variant summary

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

The NM_004993.6(ATXN3):​c.915_916insCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAG​(p.Gln305_Gly306insGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGln) 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 0.000042 (0 hom., cov: 20)
  • Exomes 𝑓: 0.000020 (0 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, 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: Likely_benign. The variant received -1 ACMG points.

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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ATXN3	NM_004993.6	c.915_916insCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAG	p.Gln305_Gly306insGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGln	conservative_inframe_insertion	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.915_916insCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAG	p.Gln305_Gly306insGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGlnGln	conservative_inframe_insertion	Exon 10 of 11		NM_004993.6	ENSP00000496695.1

Frequencies

GnomAD3 genomes AF: 0.0000421 AC: 6 AN: 142390 Hom.: 0 Cov.: 20

Gnomad AFR AF: 0.000111

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000301

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.0000198 AC: 26 AN: 1314552 Hom.: 0 Cov.: 92 AF XY: 0.0000228 AC XY: 15 AN XY: 657296

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

African (AFR) AF: 0.000218 AC: 6 AN: 27560

American (AMR) AF: 0.0000987 AC: 4 AN: 40510

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 37452

South Asian (SAS) AF: 0.0000503 AC: 4 AN: 79494

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 48912

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5148

European-Non Finnish (NFE) AF: 0.00000803 AC: 8 AN: 995972

Other (OTH) AF: 0.0000726 AC: 4 AN: 55106

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00000224569), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.0000421 AC: 6 AN: 142500 Hom.: 0 Cov.: 20 AF XY: 0.0000433 AC XY: 3 AN XY: 69226

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

African (AFR) AF: 0.000110 AC: 4 AN: 36310

American (AMR) AF: 0.00 AC: 0 AN: 14412

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

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 4310

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

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 282

European-Non Finnish (NFE) AF: 0.0000301 AC: 2 AN: 66414

Other (OTH) AF: 0.00 AC: 0 AN: 1962

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.0000884173), which strongly suggests a high chance of mosaicism in these individuals.

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

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;