3-3144680-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_182916.3(TRNT1):c.578A>G(p.Glu193Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: TRNT1 NM_182916.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.11

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.968

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TRNT1	NM_182916.3	c.578A>G	p.Glu193Gly	missense_variant	5/8	ENST00000251607.11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TRNT1	ENST00000251607.11	c.578A>G	p.Glu193Gly	missense_variant	5/8	1	NM_182916.3	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital sideroblastic anemia-B-cell immunodeficiency-periodic fever-developmental delay syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 02, 2022

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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C15"). This variant has not been reported in the literature in individuals affected with TRNT1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glutamic acid, which is acidic and polar, with glycine, which is neutral and non-polar, at codon 193 of the TRNT1 protein (p.Glu193Gly). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.92
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.33
Cadd	Pathogenic	30
Dann	Pathogenic	1.0
DEOGEN2	Uncertain	0.62	D;.
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Pathogenic	0.34	D
MetaRNN	Pathogenic	0.97	D;D
MetaSVM	Uncertain	0.63	D
MutationAssessor	Pathogenic	4.3	H;H
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.65	T
PROVEAN	Pathogenic	-6.9	D;D
REVEL	Pathogenic	0.77
Sift	Pathogenic	0.0	D;D
Sift4G	Uncertain	0.0020	D;D
Polyphen		1.0	D;D
Vest4		0.93
MutPred		0.82		Gain of MoRF binding (P = 0.1074);Gain of MoRF binding (P = 0.1074);
MVP		0.93
MPC		0.018
ClinPred		1.0	D
GERP RS		5.9
Varity_R		0.74
gMVP		0.95

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.24		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.24		Position offset: 30

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr3-3186364;