chr18-31591937-C-T

Variant names:

• chr18-31591937-C-T
• rs2073488167
• NM_000371.4:c.35C>T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP2

The NM_000371.4(TTR):​c.35C>T​(p.Ala12Val) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A12S) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: TTR NM_000371.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.09
• Publications: 0 publications found

Genes affected

TTR (HGNC:12405): (transthyretin) This gene encodes one of the three prealbumins, which include alpha-1-antitrypsin, transthyretin and orosomucoid. The encoded protein, transthyretin, is a homo-tetrameric carrier protein, which transports thyroid hormones in the plasma and cerebrospinal fluid. It is also involved in the transport of retinol (vitamin A) in the plasma by associating with retinol-binding protein. The protein may also be involved in other intracellular processes including proteolysis, nerve regeneration, autophagy and glucose homeostasis. Mutations in this gene are associated with amyloid deposition, predominantly affecting peripheral nerves or the heart, while a small percentage of the gene mutations are non-amyloidogenic. The mutations are implicated in the etiology of several diseases, including amyloidotic polyneuropathy, euthyroid hyperthyroxinaemia, amyloidotic vitreous opacities, cardiomyopathy, oculoleptomeningeal amyloidosis, meningocerebrovascular amyloidosis and carpal tunnel syndrome. [provided by RefSeq, Aug 2017]

TTR Gene-Disease associations (from GenCC):

• amyloidosis, hereditary systemic 1

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
• familial amyloid neuropathy

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• hereditary ATTR amyloidosis

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• heart conduction disease

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• ATTRV122I amyloidosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 108 curated pathogenic missense variants (we use a threshold of 10). The gene has 3 curated benign missense variants. Gene score misZ: 1.0149 (below the threshold of 3.09). Trascript score misZ: 1.5458 (below the threshold of 3.09). GenCC associations: The gene is linked to familial amyloid neuropathy, amyloidosis, hereditary systemic 1, ATTRV122I amyloidosis, hereditary ATTR amyloidosis, heart conduction disease.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000371.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTR	NM_000371.4	MANE Select	c.35C>T	p.Ala12Val	missense	Exon 1 of 4	NP_000362.1	P02766

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TTR	ENST00000237014.8	TSL:1 MANE Select	c.35C>T	p.Ala12Val	missense	Exon 1 of 4	ENSP00000237014.4	P02766
	TTR	ENST00000649620.1		c.35C>T	p.Ala12Val	missense	Exon 3 of 6	ENSP00000497927.1	P02766
	TTR	ENST00000858988.1		c.35C>T	p.Ala12Val	missense	Exon 3 of 6	ENSP00000529047.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Amyloidosis, hereditary systemic 1 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Uncertain	0.13
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.45	T
Eigen	Pathogenic	0.69
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Uncertain	0.93	D
M_CAP	Pathogenic	0.40	D
MetaRNN	Uncertain	0.70	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.6	M
PhyloP100		4.1
PrimateAI	Uncertain	0.50	T
PROVEAN	Benign	-1.6	N
REVEL	Pathogenic	0.67
Sift	Uncertain	0.0070	D
Sift4G	Uncertain	0.022	D
Polyphen		1.0	D
Vest4		0.51
MutPred		0.47		Loss of helix (P = 0.3949)
MVP		0.96
MPC		1.1
ClinPred		0.98	D
GERP RS		5.8
PromoterAI		-0.00040	Neutral
Varity_R		0.35
gMVP		0.94
Mutation Taster		=48/52	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: rs2073488167; hg19: chr18-29171900;