chr21-31118563-G-C

Variant names:

• chr21-31118563-G-C
• rs747860689
• NM_001353694.2:c.*1805C>G

Variant summary

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

The NM_001353694.2(TIAM1):​c.*1805C>G variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000125 in 471,594 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.00031 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000038 (0 hom.)
• Consequence: TIAM1 NM_001353694.2 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.62

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 (BayesDel_noAF=-0.44).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TIAM1	NM_001353694.2	c.*1805C>G		3_prime_UTR_variant	Exon 28 of 28	ENST00000541036.6	NP_001340623.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TIAM1	ENST00000541036	c.*1805C>G		3_prime_UTR_variant	Exon 28 of 28	5	NM_001353694.2	ENSP00000441570.2

Frequencies

GnomAD3 genomes AF: 0.000309 AC: 47 AN: 152108 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00109

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

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: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000780 AC: 12 AN: 153850 Hom.: 0 AF XY: 0.0000243 AC XY: 2 AN XY: 82138

Gnomad AFR exome AF: 0.00153

Gnomad AMR exome AF: 0.0000406

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000376 AC: 12 AN: 319486 Hom.: 0 Cov.: 0 AF XY: 0.0000333 AC XY: 6 AN XY: 180420

Gnomad4 AFR exome AF: 0.00127

Gnomad4 AMR exome AF: 0.0000367

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 AF: 0.000309 AC: 47 AN: 152108 Hom.: 0 Cov.: 32 AF XY: 0.000350 AC XY: 26 AN XY: 74294

Gnomad4 AFR AF: 0.00109

Gnomad4 AMR AF: 0.000131

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000214 Hom.: 0

Bravo AF: 0.000310

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Nov 06, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: TIAM1 c.*1805C>G is located in the untranslated mRNA region downstream of the termination codon. The variant allele was found at a frequency of 7.8e-05 in 153850 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in TIAM1 causing Neurodevelopmental Disorder With Language Delay And Seizures, allowing no conclusion about variant significance. To our knowledge, no occurrence of c.*1805C>G in individuals affected with Neurodevelopmental Disorder With Language Delay And Seizures and no experimental evidence demonstrating its impact on protein function have been reported. No submitters have cited clinical-significance assessments for this variant to ClinVar. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.44
CADD	Benign	14
DANN	Benign	0.92

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: rs747860689; hg19: chr21-32490881;