3-3144694-A-G

Variant names:

• chr3-3144694-A-G
• rs757780903
• NM_182916.3:c.592A>G

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1 PM2

The NM_182916.3(TRNT1):​c.592A>G​(p.Ile198Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. I198L) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TRNT1 NM_182916.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.04
• Publications: 0 publications found

Genes affected

TRNT1 (HGNC:17341): (tRNA nucleotidyl transferase 1) The protein encoded by this gene is a CCA-adding enzyme which belongs to the tRNA nucleotidyltransferase/poly(A) polymerase family. This essential enzyme functions by catalyzing the addition of the conserved nucleotide triplet CCA to the 3' terminus of tRNA molecules. Mutations in this gene result in sideroblastic anemia with B-cell immunodeficiency, periodic fevers, and developmental delay. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2014]

CRBN (HGNC:30185): (cereblon) This gene encodes a protein related to the Lon protease protein family. In rodents and other mammals this gene product is found in the cytoplasm localized with a calcium channel membrane protein, and is thought to play a role in brain development. Mutations in this gene are associated with autosomal recessive nonsyndromic cognitive disability. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Mar 2010]

CRBN Gene-Disease associations (from GenCC):

• intellectual disability

  Inheritance: AR Classification: MODERATE Submitted by: ClinGen
• autosomal recessive non-syndromic intellectual disability

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• intellectual disability, autosomal recessive 2

  Inheritance: AR Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae), G2P

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_182916.3
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TRNT1	NM_182916.3	c.592A>G	p.Ile198Val	missense_variant	Exon 5 of 8	ENST00000251607.11	NP_886552.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TRNT1	ENST00000251607.11	c.592A>G	p.Ile198Val	missense_variant	Exon 5 of 8	1	NM_182916.3	ENSP00000251607.6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.25
BayesDel_addAF	Uncertain	0.098	D
BayesDel_noAF	Benign	-0.10
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.078	T;.
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	.;D
M_CAP	Benign	0.019	T
MetaRNN	Uncertain	0.72	D;D
MetaSVM	Benign	-0.54	T
MutationAssessor	Uncertain	2.7	M;M
PhyloP100		9.0
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	-0.90	N;N
REVEL	Benign	0.22
Sift	Uncertain	0.025	D;D
Sift4G	Uncertain	0.031	D;D
Polyphen		0.97	D;D
Vest4		0.73
MutPred		0.58		Gain of methylation at R203 (P = 0.1193);Gain of methylation at R203 (P = 0.1193);
MVP		0.39
MPC		0.015
ClinPred		0.96	D
GERP RS		5.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.36
gMVP		0.78
Mutation Taster		=47/53	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: rs757780903; hg19: chr3-3186378;