2-46978834-C-T

Position:

• chr2-46978834-C-T

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_020458.4(TTC7A):​c.691C>T​(p.Pro231Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,842 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: TTC7A NM_020458.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.501

Genes affected

TTC7A (HGNC:19750): (tetratricopeptide repeat domain 7A) This gene encodes a protein containing tetratricopeptide repeats. Mutations in this gene disrupt intestinal development and can cause early onset inflammatory bowel disease and intestinal atresia. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jun 2014]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.057584107).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTC7A	NM_020458.4	c.691C>T	p.Pro231Ser	missense_variant	5/20	ENST00000319190.11	NP_065191.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTC7A	ENST00000319190.11	c.691C>T	p.Pro231Ser	missense_variant	5/20	2	NM_020458.4	ENSP00000316699.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461842 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 727224

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Multiple gastrointestinal atresias Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 21, 2024

This sequence change replaces proline, which is neutral and non-polar, with serine, which is neutral and polar, at codon 231 of the TTC7A protein (p.Pro231Ser). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TTC7A-related conditions. ClinVar contains an entry for this variant (Variation ID: 582990). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt TTC7A protein function with a negative predictive value of 80%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.071
BayesDel_addAF	Benign	-0.27	T
BayesDel_noAF	Benign	-0.62
CADD	Benign	8.7
DANN	Benign	0.67
DEOGEN2	Benign	0.18	.;T;.
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.10	N
LIST_S2	Benign	0.69	T;T;T
M_CAP	Benign	0.0033	T
MetaRNN	Benign	0.058	T;T;T
MetaSVM	Benign	-0.99	T
MutationAssessor	Benign	0.51	.;N;N
PrimateAI	Benign	0.26	T
PROVEAN	Benign	-1.6	N;N;N
REVEL	Benign	0.033
Sift	Benign	0.31	T;T;T
Sift4G	Benign	0.33	T;T;T
Polyphen		0.0	B;B;.
Vest4		0.22
MutPred		0.34		.;Gain of catalytic residue at P231 (P = 0.052);Gain of catalytic residue at P231 (P = 0.052);
MVP		0.081
MPC		0.063
ClinPred		0.046	T
GERP RS		2.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.023
gMVP		0.13

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: rs1006086423; hg19: chr2-47205973;