rs121918083

Variant names:

• chr18-31592914-T-C
• rs121918083
• NM_000371.4:c.88T>C

Your query was ambiguous. Multiple possible variants found:

• chr18-31592914-T-C
• chr18-31592914-T-G

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate PP5

The NM_000371.4(TTR):​c.88T>C​(p.Cys30Arg) variant causes a missense change. The variant allele was found at a frequency of 0.00000124 in 1,613,960 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C30G) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TTR NM_000371.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:6 U:1
• Conservation: PhyloP100: 4.49
• Publications: 7 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: Pathogenic. The variant received 10 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 9 uncertain 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 chr18-31592915-G-A is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 1490986.Status of the report is criteria_provided_single_submitter, 1 stars.
• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.939
• PP5: Variant 18-31592914-T-C is Pathogenic according to our data. Variant chr18-31592914-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 13444.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTR	NM_000371.4	c.88T>C	p.Cys30Arg	missense_variant	Exon 2 of 4	ENST00000237014.8	NP_000362.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTR	ENST00000237014.8	c.88T>C	p.Cys30Arg	missense_variant	Exon 2 of 4	1	NM_000371.4	ENSP00000237014.4

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152240 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461720 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727168

African (AFR) AF: 0.00 AC: 0 AN: 33472

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.00 AC: 0 AN: 86248

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53396

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111910

Other (OTH) AF: 0.00 AC: 0 AN: 60378

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152240 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74374

African (AFR) AF: 0.00 AC: 0 AN: 41464

American (AMR) AF: 0.00 AC: 0 AN: 15292

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5202

South Asian (SAS) AF: 0.00 AC: 0 AN: 4836

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68040

Other (OTH) AF: 0.00 AC: 0 AN: 2090

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:6 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Amyloidosis, hereditary systemic 1 Pathogenic:4

Dec 01, 1992

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Jan 24, 2022

MGZ Medical Genetics Center

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 05, 2016

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

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant Summary: The c.88T>C variant involves the alteration of a conserved nucleotide and 4/4 in silico tools predict a pathogenic outcome. The variant, also known as Cys10Arg, involves the only free Cysteine in TTR and is hypothesized to cause structural changes in the heterozygous TTR dimer and tetramer that lead to polymerization of TTR molecules (Uemichi_1992). The variant is absent from the large, broad ExAC control population. The variant was found in multiple affected individuals in the literature, including a family in which all tested affected males carried the variant while three unaffected females also carried the variant, suggesting some role of sex in the occurrence of disease (Uemichi_1992). One clinical lab has classified the variant as "pathogenic". Therefore, taken together, this variant has been classified as Likely Pathogenic. -

Nov 05, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces cysteine, which is neutral and slightly polar, with arginine, which is basic and polar, at codon 30 of the TTR protein (p.Cys30Arg). This variant is present in population databases (rs121918083, gnomAD 0.007%). This missense change has been observed in individual(s) with clinical features of hereditary transthyretin-mediated amyloidosis (hATTR amyloidosis) (PMID: 1362222, 24664531; internal data). It has also been observed to segregate with disease in related individuals. This variant is also known as Cys10Arg. ClinVar contains an entry for this variant (Variation ID: 13444). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt TTR protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:2

Aug 01, 2020

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 28, 2024

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The frequency of this variant in the general population is consistent with pathogenicity. (http://gnomad.broadinstitute.org) This variant has been identified in multiple unrelated individuals with clinical features associated with autosomal dominant hereditary transthyretin-related amyloidosis. This variant has been identified in at least one family with clinical features associated with this gene, where incomplete penetrance was noted (PMID: 1362222). In some published literature, this variant is referred to as p.Cys10Arg. Computational tools predict that this variant is damaging. -

Cardiovascular phenotype Uncertain:1

Jun 06, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.C30R variant (also known as c.88T>C), located in coding exon 2 of the TTR gene, results from a T to C substitution at nucleotide position 88. The cysteine at codon 30 is replaced by arginine, an amino acid with highly dissimilar properties. This alteration, which is also known as p.C10R, has been reported in transthyretin (TTR) amyloidosis and related cardiomyopathy cohorts; however, clinical details were limited (Uemichi T et al. J Med Genet, 1992 Dec;29:888-91; Suhr OB et al. Transplantation, 2016 Feb;100:373-81; Ungerer MN et al. Amyloid, 2021 Jun;28:91-99). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.74
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.48
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.68	D;D;T;.
Eigen	Pathogenic	0.69
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Uncertain	0.78	D
LIST_S2	Benign	0.80	.;T;T;T
M_CAP	Pathogenic	0.63	D
MetaRNN	Pathogenic	0.94	D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.3	M;M;.;.
PhyloP100		4.5
PrimateAI	Uncertain	0.60	T
PROVEAN	Pathogenic	-5.1	.;D;.;.
REVEL	Pathogenic	0.90
Sift	Uncertain	0.0070	.;D;.;.
Sift4G	Uncertain	0.016	.;D;D;D
Polyphen		1.0	D;D;.;.
Vest4		0.89, 0.90, 0.94
MutPred		0.74		Gain of disorder (P = 0.0116);Gain of disorder (P = 0.0116);Gain of disorder (P = 0.0116);Gain of disorder (P = 0.0116);
MVP		0.98
MPC		1.8
ClinPred		1.0	D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.88
gMVP		1.0
Mutation Taster		=8/92	disease causing (ClinVar)

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: rs121918083; hg19: chr18-29172877;