rs114557412

Variant summary

Our verdict is Benign. The variant received -13 ACMG points: 0P and 13B. BP4_StrongBP6BS1BS2

The NM_144596.4(TTC8):​c.194A>G​(p.Asp65Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000642 in 1,613,350 control chromosomes in the GnomAD database, including 8 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D65N) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0032 ( 1 hom., cov: 32)
Exomes 𝑓: 0.00037 ( 7 hom. )

Consequence

TTC8
NM_144596.4 missense

Scores

6
7
5

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:4

Conservation

PhyloP100: 8.83

Publications

6 publications found
Variant links:
Genes affected
TTC8 (HGNC:20087): (tetratricopeptide repeat domain 8) This gene encodes a protein that has been directly linked to Bardet-Biedl syndrome. The primary features of this syndrome include retinal dystrophy, obesity, polydactyly, renal abnormalities and learning disabilities. Experimentation in non-human eukaryotes suggests that this gene is expressed in ciliated cells and that it is involved in the formation of cilia. A mutation in this gene has also been implicated in nonsyndromic retinitis pigmentosa. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2014]
TTC8 Gene-Disease associations (from GenCC):
  • Bardet-Biedl syndrome 8
    Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Genomics England PanelApp, Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P
  • retinitis pigmentosa 51
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
  • retinitis pigmentosa
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • Bardet-Biedl syndrome
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -13 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.012029707).
BP6
Variant 14-88839501-A-G is Benign according to our data. Variant chr14-88839501-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 262515.
BS1
Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00323 (492/152282) while in subpopulation AFR AF = 0.0113 (471/41566). AF 95% confidence interval is 0.0105. There are 1 homozygotes in GnomAd4. There are 219 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.
BS2
High Homozygotes in GnomAdExome4 at 7 AD,AR gene

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTC8NM_144596.4 linkc.194A>G p.Asp65Gly missense_variant Exon 3 of 15 ENST00000380656.7 NP_653197.2 Q8TAM2-4Q86U25

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTC8ENST00000380656.7 linkc.194A>G p.Asp65Gly missense_variant Exon 3 of 15 2 NM_144596.4 ENSP00000370031.2 Q8TAM2-4

Frequencies

GnomAD3 genomes
AF:
0.00323
AC:
492
AN:
152164
Hom.:
1
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0114
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.000916
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:
0.0000147
Gnomad OTH
AF:
0.00287
GnomAD2 exomes
AF:
0.000860
AC:
216
AN:
251200
AF XY:
0.000597
show subpopulations
Gnomad AFR exome
AF:
0.0119
Gnomad AMR exome
AF:
0.000434
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000352
Gnomad OTH exome
AF:
0.000490
GnomAD4 exome
AF:
0.000372
AC:
543
AN:
1461068
Hom.:
7
Cov.:
30
AF XY:
0.000323
AC XY:
235
AN XY:
726860
show subpopulations
African (AFR)
AF:
0.0134
AC:
449
AN:
33446
American (AMR)
AF:
0.000492
AC:
22
AN:
44696
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26100
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39538
South Asian (SAS)
AF:
0.0000116
AC:
1
AN:
86246
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53398
Middle Eastern (MID)
AF:
0.000521
AC:
3
AN:
5760
European-Non Finnish (NFE)
AF:
0.0000189
AC:
21
AN:
1111536
Other (OTH)
AF:
0.000779
AC:
47
AN:
60348
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.470
Heterozygous variant carriers
0
25
49
74
98
123
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Exome Hom
Variant carriers
0
20
40
60
80
100
<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:
0.00323
AC:
492
AN:
152282
Hom.:
1
Cov.:
32
AF XY:
0.00294
AC XY:
219
AN XY:
74470
show subpopulations
African (AFR)
AF:
0.0113
AC:
471
AN:
41566
American (AMR)
AF:
0.000915
AC:
14
AN:
15300
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3468
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5182
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4826
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10614
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68008
Other (OTH)
AF:
0.00284
AC:
6
AN:
2112
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.511
Heterozygous variant carriers
0
22
44
67
89
111
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
10
20
30
40
50
<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:
0.00250
Hom.:
4
Bravo
AF:
0.00372
ESP6500AA
AF:
0.0104
AC:
46
ESP6500EA
AF:
0.00
AC:
0
ExAC
AF:
0.00103
AC:
125
EpiCase
AF:
0.000109
EpiControl
AF:
0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:3Benign:4
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Bardet-Biedl syndrome 8 Uncertain:2Benign:1
Jan 13, 2018
Illumina Laboratory Services, Illumina
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Sep 17, 2021
Biomedical Genomics and Oncogenetics Laboratory, Institut Pasteur de Tunis, University Tunis El Manar
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:research

- -

Sep 17, 2021
New York Genome Center
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not specified Benign:2
-
PreventionGenetics, part of Exact Sciences
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Aug 23, 2017
Genetic Services Laboratory, University of Chicago
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Retinitis pigmentosa Uncertain:1
Jan 13, 2018
Illumina Laboratory Services, Illumina
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Bardet-Biedl syndrome Benign:1
Jan 30, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.89
BayesDel_addAF
Benign
-0.31
T
BayesDel_noAF
Benign
-0.20
CADD
Pathogenic
26
DANN
Uncertain
1.0
DEOGEN2
Benign
0.34
T;D;.;.;T;D;.;.
Eigen
Uncertain
0.52
Eigen_PC
Uncertain
0.52
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Pathogenic
0.98
D;D;D;D;.;.;.;D
MetaRNN
Benign
0.012
T;T;T;T;T;T;T;T
MetaSVM
Uncertain
0.12
D
MutationAssessor
Pathogenic
3.3
.;.;M;.;.;.;M;.
PhyloP100
8.8
PrimateAI
Uncertain
0.59
T
PROVEAN
Pathogenic
-6.5
.;.;.;.;D;D;D;D
REVEL
Uncertain
0.60
Sift
Pathogenic
0.0
.;.;.;.;D;D;D;D
Sift4G
Uncertain
0.0030
D;D;D;D;D;D;D;D
Polyphen
1.0
.;.;D;.;.;.;D;D
Vest4
0.84
MVP
0.58
MPC
0.60
ClinPred
0.092
T
GERP RS
6.0
gMVP
0.86
Mutation Taster
=205/95
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.020
Details are displayed if max score is > 0.2

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

Publications

Other links and lift over

dbSNP: rs114557412; hg19: chr14-89305845; API