rs199422223

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1_ModeratePM2PP5_Very_Strong

The NM_001386140.1(MTTP):c.2593G>T(p.Gly865*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000613 in 1,614,010 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 Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. G865G) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000064 ( 0 hom. )

Consequence

MTTP
NM_001386140.1 stop_gained

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 9.15

Publications

19 publications found

Variant links:

Genes affected

MTTP (HGNC:7467): (microsomal triglyceride transfer protein) MTP encodes the large subunit of the heterodimeric microsomal triglyceride transfer protein. Protein disulfide isomerase (PDI) completes the heterodimeric microsomal triglyceride transfer protein, which has been shown to play a central role in lipoprotein assembly. Mutations in MTP can cause abetalipoproteinemia. [provided by RefSeq, Jul 2008]

MTTP Gene-Disease associations (from GenCC):

abetalipoproteinemia
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Ambry Genetics, PanelApp Australia, G2P

MTTP links:

ENSG00000248676 (HGNC:):

ENSG00000248676 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0343 CDS is truncated, and there are 1 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 4-99622756-G-T is Pathogenic according to our data. Variant chr4-99622756-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 14243.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MTTP	NM_001386140.1 link	c.2593G>T	p.Gly865*	stop_gained	Exon 18 of 18	ENST00000265517.10	NP_001373069.1
MTTP	NM_000253.4 link	c.2593G>T	p.Gly865*	stop_gained	Exon 19 of 19		NP_000244.2	P55157-1
MTTP	NM_001300785.2 link	c.2344G>T	p.Gly782*	stop_gained	Exon 18 of 18		NP_001287714.2	P55157B7Z7X3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MTTP	ENST00000265517.10 link	c.2593G>T	p.Gly865*	stop_gained	Exon 18 of 18	1	NM_001386140.1	ENSP00000265517.5		P55157-1

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152180

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00173

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000119

AC:

AN:

251438

AF XY:

0.000140

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00268

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000264

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000636

AC:

AN:

1461830

Hom.:

Cov.:

AF XY:

0.0000729

AC XY:

AN XY:

727210

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00253

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000162

AC:

AN:

1111956

Other (OTH)

AF:

0.000149

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.481

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:

0.0000394

AC:

AN:

152180

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74344

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41436

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00173

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10612

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68046

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.517

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.000109

Hom.:

Bravo

AF:

0.0000793

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000233

AC:

ExAC

AF:

0.0000659

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Abetalipoproteinaemia

Pathogenic:5

Jul 24, 2017

Counsyl

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Sep 16, 2020

Natera, Inc.

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Apr 01, 2007

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

- -

Jun 19, 2017

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

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: The MTTP c.2593G>T (p.Gly865X) variant results in a premature termination codon, predicted to cause a truncated or absent MTTP protein due to nonsense mediated decay, which are commonly known mechanisms for disease. One in silico tool predicts a damaging outcome for this variant. This variant was found in 11/122676 control chromosomes at a frequency of 0.0000897, which does not exceed the estimated maximal expected allele frequency of a pathogenic MTTP variant (0.0010607). In the Gnomad control database which has additional ethnic subgroups, almost all carriers for this variant were of Ashkenazi Jewish origin, which supports literature evidence that this variant may be an AJ founder mutation (Benayoun_2007). The variant has been reported in numerous individuals in the literature in the homozygous state, and has been reported to result in the complete absence of MTP activity in in vitro studies and patient intestinal biopsy samples (Ricci_1995). Taken together, this variant is classified as pathogenic. -

Dec 26, 2023

Fulgent Genetics, Fulgent Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Pathogenic:2

Sep 12, 2022

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Published functional studies demonstrate disruption of the normal binding of the MTP protein with protein disulfide isomerase (PDI), indicating that the last 30 amino acid residues are required for the formation of the MTP-PDI complex (Ricci et al., 1995; Rehberg et al., 1996); Nonsense variant in the C-terminus predicted to result in protein truncation, as the last 30 amino acids are lost; This variant is associated with the following publications: (PMID: 27415407, 8939939, 7782284, 25552696, 27271787, 23475612, 23556456, 10679949, 31589614, 32041611, 17275380, 20592474) -

Jan 27, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Gly865*) in the MTTP gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 30 amino acid(s) of the MTTP protein. This variant is present in population databases (rs146064714, gnomAD 0.3%). This premature translational stop signal has been observed in individuals with MTTP-related conditions and abetalipoproteinaemia (PMID: 7782284, 8533758, 10679949, 17275380, 20592474, 27271787). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 14243). Algorithms developed to predict the effect of variants on gene product structure and function are not available or were not evaluated for this variant. Experimental studies have shown that this premature translational stop signal affects MTTP function (PMID: 7782284). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.58

BayesDel_noAF

Pathogenic

0.66

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

Eigen

Pathogenic

1.2

Eigen_PC

Pathogenic

1.0

FATHMM_MKL

Pathogenic

0.99

PhyloP100

9.1

Vest4

0.55

GERP RS

6.2

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over