18-31593019-G-T

Position:

• chr18-31593019-G-T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PS1_Moderate PM1 PM2 PM5 PP3_Moderate PP5

The NM_000371.4(TTR):​c.193G>T​(p.Ala65Ser) variant causes a missense change. 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 Lovd as Pathogenic (no stars). Another nucleotide change resulting in same amino acid change has been previously reported as Likely pathogenicin UniProt. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A65D) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TTR NM_000371.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.69

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]

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PS1: Transcript NM_000371.4 (TTR) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in UniProt
• PM1: In a strand (size 7) in uniprot entity TTHY_HUMAN there are 21 pathogenic changes around while only 0 benign (100%) in NM_000371.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr18-31593020-C-A is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.897
• PP5: Variant 18-31593019-G-T is Pathogenic according to our data. Variant chr18-31593019-G-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTR	NM_000371.4	c.193G>T	p.Ala65Ser	missense_variant	2/4	ENST00000237014.8	NP_000362.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTR	ENST00000237014.8	c.193G>T	p.Ala65Ser	missense_variant	2/4	1	NM_000371.4	ENSP00000237014	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.097
BayesDel_addAF	Pathogenic	0.27	D
BayesDel_noAF	Pathogenic	0.15
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.78	D;D;T;.
Eigen	Uncertain	0.34
Eigen_PC	Uncertain	0.30
FATHMM_MKL	Uncertain	0.80	D
LIST_S2	Benign	0.79	.;T;T;T
M_CAP	Pathogenic	0.40	D
MetaRNN	Pathogenic	0.90	D;D;D;D
MetaSVM	Pathogenic	0.82	D
MutationAssessor	Benign	1.8	L;L;.;.
MutationTaster	Benign	1.0	D
PrimateAI	Benign	0.41	T
PROVEAN	Benign	-0.96	.;N;.;.
REVEL	Uncertain	0.58
Sift	Benign	0.14	.;T;.;.
Sift4G	Benign	0.22	.;T;T;T
Polyphen		0.85	P;P;.;.
Vest4		0.47, 0.60, 0.77
MutPred		0.74		Gain of glycosylation at A65 (P = 0.0344);Gain of glycosylation at A65 (P = 0.0344);Gain of glycosylation at A65 (P = 0.0344);Gain of glycosylation at A65 (P = 0.0344);
MVP		1.0
MPC		0.99
ClinPred		0.78	D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.65
gMVP		0.93

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: rs121918078; hg19: chr18-29172982;