NM_001377405.1:c.118_119insAGCAGCCGCCGCCGC

Variant summary

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

The NM_001377405.1(ATXN7):​c.118_119insAGCAGCCGCCGCCGC​(p.Gln39_Pro40insGlnGlnProProPro) variant causes a disruptive inframe insertion change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000099 in 1,212,660 control chromosomes in the GnomAD database, including 1 homozygotes. 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 0.000054 ( 1 hom., cov: 31)
Exomes 𝑓: 0.0000038 ( 0 hom. )

Consequence

ATXN7
NM_001377405.1 disruptive_inframe_insertion

Scores

Not classified

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 0.825

Publications

3 publications found
Variant links:
Genes affected
ATXN7 (HGNC:10560): (ataxin 7) The autosomal dominant cerebellar ataxias (ADCA) are a heterogeneous group of neurodegenerative disorders characterized by progressive degeneration of the cerebellum, brain stem and spinal cord. Clinically, ADCA has been divided into three groups: ADCA types I-III. ADCAI is genetically heterogeneous, with five genetic loci, designated spinocerebellar ataxia (SCA) 1, 2, 3, 4 and 6, being assigned to five different chromosomes. ADCAII, which always presents with retinal degeneration (SCA7), and ADCAIII often referred to as the 'pure' cerebellar syndrome (SCA5), are most likely homogeneous disorders. Several SCA genes have been cloned and shown to contain CAG repeats in their coding regions. ADCA is caused by the expansion of the CAG repeats, producing an elongated polyglutamine tract in the corresponding protein. The expanded repeats are variable in size and unstable, usually increasing in size when transmitted to successive generations. This locus has been mapped to chromosome 3, and it has been determined that the diseased allele associated with spinocerebellar ataxia-7 contains 37-306 CAG repeats (near the N-terminus), compared to 4-35 in the normal allele. The encoded protein is a component of the SPT3/TAF9/GCN5 acetyltransferase (STAGA) and TBP-free TAF-containing (TFTC) chromatin remodeling complexes, and it thus plays a role in transcriptional regulation. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2016]
ATXN7 Gene-Disease associations (from GenCC):
  • spinocerebellar ataxia 7
    Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
  • spinocerebellar ataxia type 7
    Inheritance: AD Classification: MODERATE, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics

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ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -1 ACMG points.

BP3
Nonframeshift variant in repetitive region in NM_001377405.1

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001377405.1. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
ATXN7
NM_001377405.1
MANE Select
c.118_119insAGCAGCCGCCGCCGCp.Gln39_Pro40insGlnGlnProProPro
disruptive_inframe_insertion
Exon 3 of 13NP_001364334.1O15265-1
ATXN7
NM_001177387.1
c.118_119insAGCAGCCGCCGCCGCp.Gln39_Pro40insGlnGlnProProPro
disruptive_inframe_insertion
Exon 2 of 13NP_001170858.1O15265-2
ATXN7
NM_000333.4
c.118_119insAGCAGCCGCCGCCGCp.Gln39_Pro40insGlnGlnProProPro
disruptive_inframe_insertion
Exon 3 of 13NP_000324.1O15265-1

Ensembl Transcripts

Sel.
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
ATXN7
ENST00000674280.1
MANE Select
c.118_119insAGCAGCCGCCGCCGCp.Gln39_Pro40insGlnGlnProProPro
disruptive_inframe_insertion
Exon 3 of 13ENSP00000501377.1O15265-1
ATXN7
ENST00000295900.10
TSL:1
c.118_119insAGCAGCCGCCGCCGCp.Gln39_Pro40insGlnGlnProProPro
disruptive_inframe_insertion
Exon 3 of 13ENSP00000295900.6O15265-1
ATXN7
ENST00000522345.2
TSL:2
c.118_119insAGCAGCCGCCGCCGCp.Gln39_Pro40insGlnGlnProProPro
disruptive_inframe_insertion
Exon 1 of 12ENSP00000428067.2O15265-2

Frequencies

GnomAD3 genomes
AF:
0.0000545
AC:
8
AN:
146902
Hom.:
1
Cov.:
31
show subpopulations
Gnomad AFR
AF:
0.0000992
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.000839
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00
Gnomad OTH
AF:
0.00
GnomAD4 exome
AF:
0.00000375
AC:
4
AN:
1065650
Hom.:
0
Cov.:
32
AF XY:
0.00000392
AC XY:
2
AN XY:
510606
show subpopulations
⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.0000955
AC:
2
AN:
20932
American (AMR)
AF:
0.00
AC:
0
AN:
11452
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
13278
East Asian (EAS)
AF:
0.00
AC:
0
AN:
19748
South Asian (SAS)
AF:
0.0000770
AC:
2
AN:
25960
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
31604
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
2714
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
899674
Other (OTH)
AF:
0.00
AC:
0
AN:
40288
⚠️ 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.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.250
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000544
AC:
8
AN:
147010
Hom.:
1
Cov.:
31
AF XY:
0.0000419
AC XY:
3
AN XY:
71548
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.0000989
AC:
4
AN:
40428
American (AMR)
AF:
0.00
AC:
0
AN:
14886
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3390
East Asian (EAS)
AF:
0.00
AC:
0
AN:
4808
South Asian (SAS)
AF:
0.000840
AC:
4
AN:
4762
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
9136
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
286
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
66358
Other (OTH)
AF:
0.00
AC:
0
AN:
2048
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.0101053), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.392
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Genome Hom
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.00
Hom.:
0

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name
Calibrated prediction
Score
Prediction
PhyloP100
0.82
Mutation Taster
=81/19
polymorphism

Splicing

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

Publications

Other links and lift over

dbSNP: rs770364745; hg19: chr3-63898390; API