18-31594224-G-A

Position:

• chr18-31594224-G-A

Variant summary

Our verdict is Benign. Variant got -12 ACMG points: 0P and 12B. BP4_Strong BA1

The NM_000371.4(TTR):​c.201-896G>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0286 in 152,190 control chromosomes in the GnomAD database, including 210 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 0.029 (210 hom., cov: 32)
• Consequence: TTR NM_000371.4 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.202

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 Benign. Variant got -12 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.85).
• BA1: GnomAd4 highest subpopulation (AFR) allele frequency at 95% confidence interval = 0.0973 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTR	NM_000371.4	c.201-896G>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.201-896G>A		intron_variant		1	NM_000371.4	ENSP00000237014	P1
TTR	ENST00000610404.5	c.105-896G>A		intron_variant		5		ENSP00000477599
TTR	ENST00000649620.1	c.201-896G>A		intron_variant				ENSP00000497927	P1
TTR	ENST00000541025.2	n.227-896G>A		intron_variant, non_coding_transcript_variant		2

Frequencies

GnomAD3 genomes AF: 0.0286 AC: 4349 AN: 152078 Hom.: 211 Cov.: 32

Gnomad AFR AF: 0.100

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00877

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000192

Gnomad SAS AF: 0.000622

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00316

Gnomad NFE AF: 0.000323

Gnomad OTH AF: 0.0202

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

GnomAD4 genome AF: 0.0286 AC: 4348 AN: 152190 Hom.: 210 Cov.: 32 AF XY: 0.0274 AC XY: 2041 AN XY: 74414

Gnomad4 AFR AF: 0.0999

Gnomad4 AMR AF: 0.00876

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000193

Gnomad4 SAS AF: 0.000622

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000323

Gnomad4 OTH AF: 0.0199

Alfa AF: 0.0175 Hom.: 22

Bravo AF: 0.0329

Asia WGS AF: 0.00462 AC: 17 AN: 3478

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.85
CADD	Benign	1.9
DANN	Benign	0.38

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: rs13381331; hg19: chr18-29174187;