GENE REFERENCE / HGNC:12404

TTPA

alpha tocopherol transfer protein

protein-coding gene8q12.3Gene information

What does this gene do?

The TTPA gene provides instructions for making the α-tocopherol transfer protein (αTTP), which is found in the liver and brain. This protein controls the distribution of vitamin E obtained from the diet (also called α-tocopherol) to cells and tissues throughout the body. Vitamin E is an antioxidant that protects cells in the body from the damaging effects of unstable molecules called free radicals. Normally, vitamin E derived from food is absorbed in the intestine and then transported into the liver on molecules called chylomicrons.

After a meal, chylomicrons are formed to transport fat-soluble vitamins (such as vitamin E), dietary fats, and cholesterol from the intestine to the liver. Once in the liver, αTTP transfers vitamin E from chylomicrons to very low-density lipoproteins (VLDLs), which carry fat, fat-soluble vitamins, and cholesterol from the liver to other tissues throughout the body. The VLDLs are then released into the bloodstream so the accompanying vitamin E can be used in the body. The αTTP protein is also thought to transport vitamin E to nerve cells (neurons) in the brain.

Source: MedlinePlus, National Library of Medicine. Source publication: 2023-05-04. Source review: 2008-04.

ClinGen reviews

We found no matching ClinGen review in the data used here. This does not rule out a link between the gene and a condition.

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles: 542
Submissions for variants in or overlapping this gene: 897
Submissions explicitly reporting this gene: 855
Alleles reported pathogenic / likely pathogenic: 107
VariationIDs with uncertain significance: 187
VariationIDs with conflicting classifications: 13

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about TTPA?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 107 alleles in TTPA reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in TTPA.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

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