NM_144596.4:c.1124A>T

Variant names:

• chr14-88871623-A-T
• rs774216735
• NM_144596.4:c.1124A>T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_144596.4(TTC8):​c.1124A>T​(p.Gln375Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000109 in 1,461,840 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: 0.000011 (0 hom.)
• Consequence: TTC8 NM_144596.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 8.96

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 Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.753

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTC8	NM_144596.4	c.1124A>T	p.Gln375Leu	missense_variant	Exon 12 of 15	ENST00000380656.7	NP_653197.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTC8	ENST00000380656.7	c.1124A>T	p.Gln375Leu	missense_variant	Exon 12 of 15	2	NM_144596.4	ENSP00000370031.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251242 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135780

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000109 AC: 16 AN: 1461840 Hom.: 0 Cov.: 32 AF XY: 0.00000963 AC XY: 7 AN XY: 727228

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: 0.0000144

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	0.25	D
BayesDel_noAF	Uncertain	0.13
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Benign	0.34	T;T;T;.;.;T;T;.;.
Eigen	Uncertain	0.56
Eigen_PC	Uncertain	0.63
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.91	D;D;D;D;D;.;.;D;.
M_CAP	Uncertain	0.13	D
MetaRNN	Pathogenic	0.75	D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	-0.21	T
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-6.4	.;.;D;.;.;D;D;D;D
REVEL	Pathogenic	0.65
Sift	Uncertain	0.023	.;.;D;.;.;D;D;D;D
Sift4G	Uncertain	0.028	D;D;D;D;D;D;D;D;D
Polyphen		1.0, 1.0	.;.;.;D;.;.;.;D;D
Vest4		0.77
MVP		0.73
MPC		0.49
ClinPred		0.99	D
GERP RS		5.9
gMVP		0.68

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs774216735; hg19: chr14-89337967; COSMIC: COSV57629370;