4-99574916-CT-C

Variant names:

• chr4-99574916-CT-C
• NM_001386140.1:c.9delT

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_001386140.1(MTTP):​c.9delT​(p.Ala5LeufsTer24) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MTTP NM_001386140.1 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 3.90

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]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 29 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-99574916-CT-C is Pathogenic according to our data. Variant chr4-99574916-CT-C is described in ClinVar as [Pathogenic]. Clinvar id is 2728721.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MTTP	NM_001386140.1	c.9delT	p.Ala5LeufsTer24	frameshift_variant	Exon 1 of 18	ENST00000265517.10	NP_001373069.1
MTTP	NM_000253.4	c.9delT	p.Ala5LeufsTer24	frameshift_variant	Exon 2 of 19		NP_000244.2
MTTP	NM_001300785.2	c.-188-6987delT		intron_variant	Intron 1 of 17		NP_001287714.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MTTP	ENST00000265517.10	c.9delT	p.Ala5LeufsTer24	frameshift_variant	Exon 1 of 18	1	NM_001386140.1	ENSP00000265517.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Jun 25, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with MTTP-related conditions. For these reasons, this variant has been classified as Pathogenic. This sequence change creates a premature translational stop signal (p.Ala5Leufs*24) in the MTTP gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MTTP are known to be pathogenic (PMID: 8533758, 9671739). -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr4-100496073;