Cells use sections of DNA called genes to make proteins and other molecules that they need to function.
Each set of three nucleotides in a gene corresponds to a particular amino acid – when the cells of your body read the sequence of a gene, the corresponding amino acids are assembled into a chain to make a protein.
Differences in your DNA sequence contribute to your individuality, and also affect the way your body functions. These differences are known as variants.
Variants in genes can change the product that is made – they might cause the gene to produce a non-functioning protein, or sometimes no protein at all.
Long QT syndrome
Ion channel proteins control the beating of the heart by transporting charged ions in and out of the cell.
In long QT syndrome, genetic variants can cause a shortened amino acid chain (top image), leading to a non-functional ion channel protein that is unable to transport ions effectively (centre image).
This causes an irregular heartbeat, or arrhythmia (bottom image).
Tags: image, DNA, variant, protein, genetic disease
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