21-31130216-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001353694.2(TIAM1):c.4042G>A(p.Ala1348Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000149 in 1,613,686 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000015 (0 hom.)
• Consequence: TIAM1 NM_001353694.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.85

Genes affected

TIAM1 (HGNC:11805): (TIAM Rac1 associated GEF 1) This gene encodes a RAC1-specific guanine nucleotide exchange factor (GEF). GEFs mediate the exchange of guanosine diphosphate (GDP) for guanosine triphosphate (GTP). The binding of GTP induces a conformational change in RAC1 that allows downstream effectors to bind and transduce a signal. This gene thus regulates RAC1 signaling pathways that affect cell shape, migration, adhesion, growth, survival, and polarity, as well as influencing actin cytoskeletal formation, endocytosis, and membrane trafficking. This gene thus plays an important role in cell invasion, metastasis, and carcinogenesis. In addition to RAC1, the encoded protein activates additional Rho-like GTPases such as CDC42, RAC2, RAC3 and RHOA. This gene encodes multiple protein isoforms that experience a diverse array of intramolecular, protein-protein, and phosphorylation interactions as well as phosphoinositide binding. Both the longer and shorter isoforms have C-terminal Dbl homology (DH) and pleckstrin homology (PH) domains while only the longer isoforms of this gene have the N-terminal myristoylation site and the downstream N-terminal PH domain, ras-binding domain (RBD), and PSD-95/DlgA/ZO-1 (PDZ) domain. [provided by RefSeq, Jul 2017]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.08020079).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TIAM1	NM_001353694.2	c.4042G>A	p.Ala1348Thr	missense_variant	25/28	ENST00000541036.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TIAM1	ENST00000541036.6	c.4042G>A	p.Ala1348Thr	missense_variant	25/28	5	NM_001353694.2	P1

Frequencies

GnomAD3 genomes AF: 0.0000132 AC: 2 AN: 152048 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000199 AC: 5 AN: 251346 Hom.: 0 AF XY: 0.0000294 AC XY: 4 AN XY: 135840

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: 0.0000440

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000151 AC: 22 AN: 1461638 Hom.: 0 Cov.: 31 AF XY: 0.0000124 AC XY: 9 AN XY: 727124

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: 0.0000198

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000132 AC: 2 AN: 152048 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74246

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000434 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 14, 2023

The c.4042G>A (p.A1348T) alteration is located in exon 26 (coding exon 22) of the TIAM1 gene. This alteration results from a G to A substitution at nucleotide position 4042, causing the alanine (A) at amino acid position 1348 to be replaced by a threonine (T). 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	0.068
BayesDel_addAF	Benign	-0.28	T
BayesDel_noAF	Benign	-0.58
Cadd	Benign	23
Dann	Benign	0.95
DEOGEN2	Benign	0.15	T;.;T
Eigen	Benign	-0.52
Eigen_PC	Benign	-0.31
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Benign	0.73	T;T;T
M_CAP	Benign	0.013	T
MetaRNN	Benign	0.080	T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.34	N;.;.
MutationTaster	Benign	0.99	D;D
PrimateAI	Uncertain	0.61	T
PROVEAN	Benign	-0.96	N;N;.
REVEL	Benign	0.053
Sift	Benign	0.21	T;T;.
Sift4G	Benign	0.40	T;T;.
Polyphen		0.022	B;.;.
Vest4		0.19
MutPred		0.27		Gain of sheet (P = 0.0827);.;.;
MVP		0.13
MPC		0.24
ClinPred		0.15	T
GERP RS		4.2
Varity_R		0.033
gMVP		0.33

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs769275298; hg19: chr21-32502534; COSMIC: COSV54559451;