14-88839501-A-T

Variant names:

• chr14-88839501-A-T
• rs114557412
• NM_144596.4:c.194A>T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_001288782.1(TTC8):​c.-399A>T variant causes a 5 prime UTR premature start codon gain change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,068 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TTC8 NM_001288782.1 5_prime_UTR_premature_start_codon_gain
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 8.83

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.966

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTC8	NM_144596.4	c.194A>T	p.Asp65Val	missense_variant	Exon 3 of 15	ENST00000380656.7	NP_653197.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTC8	ENST00000380656.7	c.194A>T	p.Asp65Val	missense_variant	Exon 3 of 15	2	NM_144596.4	ENSP00000370031.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251200 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135776

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461068 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 726860

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.080
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Benign	0.40	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
M_CAP	Uncertain	0.11	D
MetaRNN	Pathogenic	0.97	D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.22	D
MutationAssessor	Pathogenic	3.3	.;.;M;.;.;.;M;.
PrimateAI	Uncertain	0.57	T
PROVEAN	Pathogenic	-8.4	.;.;.;.;D;D;D;D
REVEL	Pathogenic	0.72
Sift	Pathogenic	0.0	.;.;.;.;D;D;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D;D;D;D;D
Polyphen		1.0	.;.;D;.;.;.;D;D
Vest4		0.87
MutPred		0.85		.;.;Gain of helix (P = 0.062);.;.;.;Gain of helix (P = 0.062);.;
MVP		0.57
MPC		0.63
ClinPred		1.0	D
GERP RS		6.0
gMVP		0.90

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs114557412; hg19: chr14-89305845;