1-2641433-G-A

Variant names:

• chr1-2641433-G-A
• rs895222851
• NM_001242672.3:c.3175C>T

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001242672.3(TTC34):​c.3175C>T​(p.Arg1059Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000521 in 1,535,086 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1059H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000043 (0 hom.)
• Consequence: TTC34 NM_001242672.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -4.25
• Publications: 0 publications found

Genes affected

TTC34 (HGNC:34297): (tetratricopeptide repeat domain 34)

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.08082968).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTC34	NM_001242672.3	c.3175C>T	p.Arg1059Cys	missense_variant	Exon 9 of 9	ENST00000401095.9	NP_001229601.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTC34	ENST00000401095.9	c.3175C>T	p.Arg1059Cys	missense_variant	Exon 9 of 9	5	NM_001242672.3	ENSP00000383873.4
TTC34	ENST00000637179.1	c.1636C>T	p.Arg546Cys	missense_variant	Exon 7 of 7	5		ENSP00000490537.1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152128 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000750 AC: 1 AN: 133348 AF XY: 0.00

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000192

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000434 AC: 6 AN: 1382842 Hom.: 0 Cov.: 30 AF XY: 0.00000293 AC XY: 2 AN XY: 682292

African (AFR) AF: 0.00 AC: 0 AN: 31584

American (AMR) AF: 0.00 AC: 0 AN: 35592

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25108

East Asian (EAS) AF: 0.00 AC: 0 AN: 35728

South Asian (SAS) AF: 0.0000253 AC: 2 AN: 79140

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 33798

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5676

European-Non Finnish (NFE) AF: 0.00000371 AC: 4 AN: 1078378

Other (OTH) AF: 0.00 AC: 0 AN: 57838

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152244 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74446

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

African (AFR) AF: 0.0000241 AC: 1 AN: 41528

American (AMR) AF: 0.00 AC: 0 AN: 15304

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5174

South Asian (SAS) AF: 0.000207 AC: 1 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67998

Other (OTH) AF: 0.00 AC: 0 AN: 2112

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.002339), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Mar 15, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1636C>T (p.R546C) alteration is located in exon 7 (coding exon 7) of the TTC34 gene. This alteration results from a C to T substitution at nucleotide position 1636, causing the arginine (R) at amino acid position 546 to be replaced by a cysteine (C). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.33	T
BayesDel_noAF	Benign	-0.68
CADD	Benign	0.0090
DANN	Benign	0.85
DEOGEN2	Benign	0.097	.;T
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.4
FATHMM_MKL	Benign	0.021	N
LIST_S2	Benign	0.74	T;.
M_CAP	Benign	0.012	T
MetaRNN	Benign	0.081	T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.69	.;N
PhyloP100		-4.3
PrimateAI	Benign	0.38	T
REVEL	Benign	0.037
MutPred		0.46		.;Loss of MoRF binding (P = 0.0072);
MVP		0.22
ClinPred		0.066	T
GERP RS		-7.1
Varity_R		0.039
gMVP		0.12
Mutation Taster		=92/8	polymorphism

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: rs895222851; hg19: chr1-2572872;