rs75517067

Positions:

• chr18-31595274-G-A
• chr18-31595274-G-C

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_Strong BP6 BS2_Supporting

The NM_000371.4(TTR):​c.336+19G>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000548 in 1,614,114 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.0028 (2 hom., cov: 32)
  • Exomes 𝑓: 0.00031 (1 hom.)
• Consequence: TTR NM_000371.4 intron
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:11
• Conservation: PhyloP100: -0.00600

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 (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -6 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.0042020977).
• BP6: Variant 18-31595274-G-A is Benign according to our data. Variant chr18-31595274-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 36891.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=4, Uncertain_significance=1, Benign=3}. Variant chr18-31595274-G-A is described in Lovd as [Benign].
• BS2: High AC in GnomAd4 at 433 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTR	NM_000371.4	c.336+19G>A		intron_variant		ENST00000237014.8	NP_000362.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTR	ENST00000237014.8	c.336+19G>A		intron_variant		1	NM_000371.4	ENSP00000237014.4
TTR	ENST00000649620.1	c.336+19G>A		intron_variant				ENSP00000497927.1
TTR	ENST00000610404.5	c.240+19G>A		intron_variant		5		ENSP00000477599.2
TTR	ENST00000541025.2	n.381G>A		non_coding_transcript_exon_variant	3/3	2

Frequencies

GnomAD3 genomes AF: 0.00284 AC: 432 AN: 152160 Hom.: 2 Cov.: 32

Gnomad AFR AF: 0.00999

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000720

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000193

Gnomad SAS AF: 0.000208

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.000956

GnomAD3 exomes AF: 0.000680 AC: 171 AN: 251300 Hom.: 1 AF XY: 0.000398 AC XY: 54 AN XY: 135806

Gnomad AFR exome AF: 0.00941

Gnomad AMR exome AF: 0.000434

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000653

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.000309 AC: 452 AN: 1461836 Hom.: 1 Cov.: 31 AF XY: 0.000257 AC XY: 187 AN XY: 727224

Gnomad4 AFR exome AF: 0.0113

Gnomad4 AMR exome AF: 0.000514

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000812

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000126

Gnomad4 OTH exome AF: 0.000464

GnomAD4 genome AF: 0.00284 AC: 433 AN: 152278 Hom.: 2 Cov.: 32 AF XY: 0.00244 AC XY: 182 AN XY: 74468

Gnomad4 AFR AF: 0.0100

Gnomad4 AMR AF: 0.000719

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000193

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000441

Gnomad4 OTH AF: 0.000946

Alfa AF: 0.000169 Hom.: 0

Bravo AF: 0.00342

ESP6500AA AF: 0.00817 AC: 36

ESP6500EA AF: 0.00 AC: 0

ExAC AF: 0.000749 AC: 91

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:11

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:1 Benign:3

Benign, criteria provided, single submitter	clinical testing	GeneDx	Mar 03, 2015	- -
Likely benign, no assertion criteria provided	clinical testing	Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)	-	- -
Likely benign, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Nov 22, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Dec 18, 2013	- -

Amyloidosis, hereditary systemic 1 Benign:3

Benign, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 31, 2024	- -
Likely benign, criteria provided, single submitter	clinical testing;curation	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Aug 18, 2011	- -
Likely benign, criteria provided, single submitter	clinical testing	Center for Advanced Laboratory Medicine, UC San Diego Health, University of California San Diego	May 20, 2019	- -

not specified Benign:2

Benign, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -
Benign, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -

Charcot-Marie-Tooth disease Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Molecular Genetics Laboratory, London Health Sciences Centre

-

- -

TTR-related disorder Benign:1

Benign, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Aug 29, 2022

This variant is classified as benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Cardiovascular phenotype Benign:1

Benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 18, 2018

This alteration is classified as benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.72	T
BayesDel_noAF	Benign	-0.80
CADD	Benign	3.0
DANN	Benign	0.41
Eigen	Benign	-0.47
Eigen_PC	Benign	-0.59
FATHMM_MKL	Benign	0.064	N
LIST_S2	Benign	0.38	T
MetaRNN	Benign	0.0042	T
MetaSVM	Benign	-1.0	T
Sift4G	Pathogenic	0.0	D
Vest4		0.24
MVP		0.11
ClinPred		0.0068	T
GERP RS		2.8

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: rs75517067; hg19: chr18-29175237;