Genetic Variant TTR:c.-1-500T>C (chr18-31591402-T-C) – ACMG Classification: Benign (-12 pts)

Variant summary

Our verdict is Benign. The variant received -12 ACMG points: 0P and 12B. BP4_StrongBS1BS2

The ENST00000649620.1(TTR):c.-1-500T>C variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0059 in 152,310 control chromosomes in the GnomAD database, including 8 homozygotes. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: 𝑓 0.0059 ( 8 hom., cov: 32)

Consequence

TTR
ENST00000649620.1 intron

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 1.30

Publications

1 publications found

Variant links:

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

TTR links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -12 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.57).

BS1

Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.0059 (898/152310) while in subpopulation AFR AF = 0.021 (872/41550). AF 95% confidence interval is 0.0198. There are 8 homozygotes in GnomAd4. There are 420 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

BS2

High AC in GnomAd4 at 898 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt

Ensembl

Gene	Transcript	HGVSc	Effect	Exon rank	TSL	Protein	UniProt
TTR	ENST00000649620.1 link	c.-1-500T>C	intron_variant	Intron 2 of 5		ENSP00000497927.1	P02766
TTR	ENST00000610404.5 link	c.-27-1494T>C	intron_variant	Intron 1 of 3	5	ENSP00000477599.2	A0A087WT59
TTR	ENST00000613781.2 link	c.-1-500T>C	intron_variant	Intron 1 of 1	5	ENSP00000479174.2	A0A087WV45
TTR	ENST00000676075.1 link	c.-1-500T>C	intron_variant	Intron 1 of 1		ENSP00000502027.1	A0A087WV45

Frequencies

GnomAD3 genomes

AF:

0.00589

AC:

896

AN:

152192

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0210

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000720

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:

0.000103

Gnomad OTH

AF:

0.00382

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome

AF:

0.00590

AC:

898

AN:

152310

Hom.:

Cov.:

AF XY:

0.00564

AC XY:

420

AN XY:

74466

show subpopulations

African (AFR)

AF:

0.0210

AC:

872

AN:

41550

American (AMR)

AF:

0.000719

AC:

AN:

15302

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10618

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000103

AC:

AN:

68034

Other (OTH)

AF:

0.00378

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.506

Heterozygous variant carriers

142

190

237

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Genome Hom

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00499

Hom.:

Bravo

AF:

0.00693

Asia WGS

AF:

0.000289

AC:

AN:

3478

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.57

CADD

Benign

(source)

DANN

Benign

0.90

PhyloP100

1.3

PromoterAI

0.068

Neutral

(source)

Splicing

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over