Glucose is the main sugar found in the blood. It is the main source of energy for all cells and its blood levels are finely regulated. Its alteration can lead to pathologies such as diabetes.
Glucose is a monosaccharide, a form of sugar. It is the most abundant organic compound in nature and is the primary source of energy for cells.
In general, sugars ingested with food are converted to glucose in metabolic processes. Glucose reaches the bloodstream to reach all tissues of the body.
Blood glucose levels vary throughout the day, between 70 and 145 milligrams per deciliter of blood, being lower on an empty stomach and rising after food intake (postprandial glycemia).
Increased glucose, measured on an empty stomach, is related to the onset of diabetes. In these cases, insulin, which is the hormone responsible for lowering blood glucose after meals, does not work properly and it accumulates in the blood. In the initial stages of alteration (also known as pre-diabetic state), changes in lifestyle habits are usually sufficient to control it.
However, sometimes high blood glucose levels maintained over time can lead to the development of diabetes. Diabetes is a chronic disease in which either there is not enough insulin, or the cells do not respond to it adequately, leaving too much sugar in the bloodstream, which over time and with poor control can cause serious health problems such as heart disease, vision loss and kidney disease.
Although blood glucose levels are especially linked to lifestyle, genetic factors have been identified that can cause these levels to vary within the physiological range.
Fasting blood glucose levels, along with other glycemic traits such as fasting insulin levels or glycated hemoglobin (HbA1c) levels, can vary depending on several factors, including genetics.
From a GWAS study of more than 200,000 participants, 70% of whom were of European descent and the remaining 30% from East Asian, African-American, South Asian and sub-Saharan African populations, 69 markers associated with fasting glucose levels have been identified.
Among the most important genes we can find the G6PC2 gene, which produces the enzyme glucose-6-phosphatase during glucose metabolism, allowing its release into the bloodstream; the MTNR1B gene, which produces a melatonin receptor or the FOXA2 gene, whose deficiency has been associated with increased insulin production in response to different amino acid concentrations.
13.5 million variants
Chen J, Spracklen CN, Marenne G, et al. The trans-ancestral genomic architecture of glycemic traits. Nature Genetics. 2021 Jun;53(6):840-860