NM_003314.3:c.677G>C

Variant names:

• chr5-160049649-G-C
• rs370202062
• NM_003314.3:c.677G>C

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP2

The NM_003314.3(TTC1):​c.677G>C​(p.Arg226Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000007 in 1,428,258 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R226K) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: TTC1 NM_003314.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 8.65
• Publications: 0 publications found

Genes affected

TTC1 (HGNC:12391): (tetratricopeptide repeat domain 1) This gene encodes a protein that belongs to the tetratrico peptide repeat superfamily of proteins. The encoded protein plays a role in protein-protein interactions, and binds to the Galpha subunit of G protein-coupled receptors to activate the Ras signaling pathway. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Sep 2013]

PWWP2A (HGNC:29406): (PWWP domain containing 2A) Enables chromatin binding activity and histone binding activity. Located in nucleus. [provided by Alliance of Genome Resources, Apr 2022]

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 1 curated pathogenic missense variants (we use a threshold of 10). The gene has 0 curated benign missense variants. Gene score misZ: 0.65922 (below the threshold of 3.09). Trascript score misZ: 0.045692 (below the threshold of 3.09).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_003314.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTC1	NM_003314.3	MANE Select	c.677G>C	p.Arg226Thr	missense	Exon 6 of 8	NP_003305.1	Q99614
	TTC1	NM_001282500.2		c.677G>C	p.Arg226Thr	missense	Exon 6 of 8	NP_001269429.1	Q99614

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTC1	ENST00000231238.10	TSL:1 MANE Select	c.677G>C	p.Arg226Thr	missense	Exon 6 of 8	ENSP00000231238.4	Q99614
	TTC1	ENST00000522793.5	TSL:5	c.677G>C	p.Arg226Thr	missense	Exon 6 of 8	ENSP00000429225.1	Q99614
	TTC1	ENST00000682719.1		c.677G>C	p.Arg226Thr	missense	Exon 6 of 8	ENSP00000507891.1	Q99614

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 7.00e-7 AC: 1 AN: 1428258 Hom.: 0 Cov.: 30 AF XY: 0.00000141 AC XY: 1 AN XY: 709946

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

African (AFR) AF: 0.00 AC: 0 AN: 31140

American (AMR) AF: 0.00 AC: 0 AN: 35132

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 24370

East Asian (EAS) AF: 0.00 AC: 0 AN: 39212

South Asian (SAS) AF: 0.00 AC: 0 AN: 79518

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52658

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5040

European-Non Finnish (NFE) AF: 9.07e-7 AC: 1 AN: 1102366

Other (OTH) AF: 0.00 AC: 0 AN: 58822

⚠️ 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.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.86
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.080
CADD	Benign	23
DANN	Uncertain	0.98
DEOGEN2	Benign	0.21	T
Eigen	Uncertain	0.50
Eigen_PC	Uncertain	0.58
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.90	D
M_CAP	Benign	0.056	D
MetaRNN	Uncertain	0.53	D
MetaSVM	Benign	-0.41	T
MutationAssessor	Uncertain	2.8	M
PhyloP100		8.7
PrimateAI	Uncertain	0.52	T
PROVEAN	Uncertain	-3.4	D
REVEL	Uncertain	0.48
Sift	Benign	0.083	T
Sift4G	Uncertain	0.045	D
Polyphen		0.74	P
Vest4		0.78
MutPred		0.32		Gain of phosphorylation at R226 (P = 0.0489)
MVP		0.86
MPC		0.19
ClinPred		0.94	D
GERP RS		5.6
Varity_R		0.42
gMVP		0.63
Mutation Taster		=19/81	disease causing

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

Other links and lift over

dbSNP: rs370202062; hg19: chr5-159476656;