NM_000370.3:c.552G>A

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM2PP3_ModeratePP5_Very_Strong

The NM_000370.3(TTPA):c.552G>A(p.Thr184Thr) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000136 in 1,613,674 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. T184T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000014 ( 0 hom. )

Consequence

TTPA
NM_000370.3 splice_region, synonymous

Scores

Splicing: ADA: 0.9999

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8

Conservation

PhyloP100: 1.04

Publications

4 publications found

Variant links:

Genes affected

TTPA (HGNC:12404): (alpha tocopherol transfer protein) This gene encodes a soluble protein that binds alpha-trocopherol, a form of vitamin E, with high selectivity and affinity. This protein plays an important role in regulating vitamin E levels in the body by transporting vitamin E between membrane vesicles and facilitating the secretion of vitamin E from hepatocytes to circulating lipoproteins. Mutations in this gene cause hereditary vitamin E deficiency (ataxia with vitamin E deficiency, AVED) and retinitis pigmentosa. [provided by RefSeq, Nov 2009]

TTPA Gene-Disease associations (from GenCC):

familial isolated deficiency of vitamin E
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Myriad Women’s Health, Labcorp Genetics (formerly Invitae)

TTPA links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 12 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.

PP5

Variant 8-63065904-C-T is Pathogenic according to our data. Variant chr8-63065904-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 374211.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000370.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTPA	NM_000370.3	MANE Select	c.552G>A	p.Thr184Thr	splice_region synonymous	Exon 3 of 5	NP_000361.1
TTPA	NM_001413418.1		c.669G>A	p.Thr223Thr	splice_region synonymous	Exon 4 of 6	NP_001400347.1
TTPA	NM_001413416.1		c.552G>A	p.Thr184Thr	splice_region synonymous	Exon 3 of 5	NP_001400345.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTPA	ENST00000260116.5	TSL:1 MANE Select	c.552G>A	p.Thr184Thr	splice_region synonymous	Exon 3 of 5	ENSP00000260116.4
TTPA	ENST00000878696.1		c.669G>A	p.Thr223Thr	splice_region synonymous	Exon 4 of 6	ENSP00000548755.1
TTPA	ENST00000878697.1		c.552G>A	p.Thr184Thr	splice_region synonymous	Exon 3 of 4	ENSP00000548756.1

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

151994

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

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

GnomAD2 exomes

AF:

0.0000199

AC:

AN:

251242

AF XY:

0.0000295

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000137

AC:

AN:

1461562

Hom.:

Cov.:

AF XY:

0.0000179

AC XY:

AN XY:

727086

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33462

American (AMR)

AF:

0.00

AC:

AN:

44704

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26122

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39678

South Asian (SAS)

AF:

0.0000348

AC:

AN:

86242

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53398

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.0000126

AC:

AN:

1111806

Other (OTH)

AF:

0.0000331

AC:

AN:

60384

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

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

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152112

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74362

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41492

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5168

South Asian (SAS)

AF:

0.00

AC:

AN:

4812

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10570

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68004

Other (OTH)

AF:

0.00

AC:

AN:

2110

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000237

Hom.:

Bravo

AF:

0.0000113

EpiCase

AF:

0.0000546

EpiControl

AF:

0.00

ClinVar

ClinVar submissions as Germline

Significance:Pathogenic/Likely pathogenic

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Familial isolated deficiency of vitamin E (5)

not provided (2)

ATAXIA, FRIEDREICH-LIKE, WITH ISOLATED VITAMIN E DEFICIENCY (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.32

CADD

Benign

(source)

DANN

Benign

0.64

PhyloP100

1.0

Mutation Taster

=21/79

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.97

SpliceAI score (max)

0.43

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.43

Position offset: 0

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over