Diabetes is a disease with a high incidence in today's society. One of the most common questions about this condition is whether it can be passed from parents to children. Therefore, in this article, we want to clarify the question of whether diabetes is hereditary, explaining the different types that exist, their origins, treatments, and most frequent complications.
How does the body control sugar levels?
Before discussing diabetes, let's briefly review how our blood sugar levels are internally controlled so we can better understand the origin of this condition. The pancreas plays a fundamental role in controlling blood sugar (glucose) levels, as it is the organ that, among many other important functions, produces insulin, the hormone responsible for regulating blood glucose levels.
The process is:
When we eat, blood glucose levels rise.
The body produces insulin, which has the function of diverting the sugar present in the blood to the tissues and muscles for use or storage.
If everything is working correctly, blood sugar levels drop and normalize relatively quickly after each meal.
Normal blood glucose and insulin levels (non-diabetic) over 24 hours.
Diabetes: when blood glucose control fails
The problem arises when the pancreas does not produce enough insulin (type 1 diabetes) or when the body does not respond (becomes resistant) to its presence (type 2 diabetes). In these cases, blood sugar levels do not return to normal after meals, leading to various problems, both in the short and long term.
Sustained high blood sugar levels (hyperglycemia) damage blood vessels and increase the risk of stroke, kidney disease, vision problems, and neurological issues. Therefore, if you have diabetes, it is essential to strictly control your blood glucose levels to prevent diabetic coma and the development of other short- and long-term health problems.
What is a diabetic coma?
Diabetic coma is a complication of diabetes that occurs when blood glucose levels rise (hyperglycemia) or fall (hypoglycemia) too low, causing loss of consciousness and unresponsiveness to stimuli. This situation can be fatal, so anyone experiencing it requires immediate medical attention.
Some symptoms that may suggest hyperglycemia include thirst, frequent urination, fatigue, dry mouth, or nausea and vomiting. Symptoms related to hypoglycemia, however, include tremors or nervousness, fatigue, weakness, sweating, slurred speech, hunger, or nausea. In patients with long-standing diabetes, a condition known as "asymptomatic hypoglycemia" can sometimes occur—a drop in blood glucose levels that does not produce any symptoms.
Diabetes is hereditary depending on its type
In articles on our blog such as Diseases and Types of Genetic Inheritance or Hereditary Genetic Diseases: The Most Common and the Rarest, we explain that hereditary genetic diseases are those caused by alterations in one or more genes that are passed down from generation to generation. But is this the case with diabetes? The answer is that it depends on the type of diabetes. Although we often think of diabetes as a single condition, the causes are different, and its degree of heritability varies. The main types are:
- Type 1 diabetes
- Type 2 diabetes
- Type 1.5 diabetes
- MODY type 2 diabetes
- Gestational diabetes
- Secondary diabetes (cystic fibrosis, medications, etc.).
Next, we will look at the main characteristics of each type of diabetes and its degree of heritability.
Type 1 diabetes
Type 1 diabetes occurs because the pancreas does not produce enough insulin to control blood glucose. This can happen for several reasons:
Genetic predisposition
The development of type 1 diabetes is due to the interaction of genetic and environmental factors. Therefore, it is not the disease itself that is inherited, but rather the likelihood of developing it. This increased risk of developing type 1 diabetes does not depend on a single gene, but is likely the result of the interaction of several genes (known or unknown), a phenomenon known as polygenic inheritance. In the case of identical twins, if one has this type of diabetes, there is a 501% chance that the other will also develop it.
Environmental factors
As with other diseases, in type 1 diabetes there are external environmental factors that can play a role in the development of the pathology, mainly in genetically predisposed individuals, such as:
Virus
- Certain environmental toxins
- Food
- Other unknown factors
Autoimmunity
In certain cases, the body itself attacks the insulin-producing cells of the pancreas (pancreatic beta cells), causing diabetes.
Type 2 diabetes
This type of diabetes is known as "adult-onset diabetes" and is most common in people over 40. The problem is that the body becomes resistant to insulin, even though production is initially adequate. Generally, the body tries to compensate for this lack of sensitivity by increasing insulin production; however, over time, this overexertion has consequences, and the pancreatic beta cells reduce their insulin production.
Genetic predisposition
In type 2 diabetes, heredity plays a more significant role than in type 1 diabetes, but we are still talking about a predisposition. That is, what is inherited is the risk of developing the disease, but in this case, there is also "polygenic inheritance" and environmental factors that influence the development of the condition. If one twin has type 2 diabetes, the probability that the other twin will also have it is 80%.
Lifestyle
The 80% risk factor for people with type 2 diabetes is obesity and a sedentary lifestyle. These two factors decrease insulin sensitivity, which is why it's so important to lead an active life and maintain a healthy weight to prevent the development of diabetes.
Type 1.5 diabetes
Type 1.5 diabetes has characteristics of both type 1 and type 2 diabetes. It is more technically known as latent autoimmune diabetes in adults (LADA). In this type of diabetes, autoimmune cells attack pancreatic cells (as in type 1 diabetes), although the disease does not appear until adulthood (as in type 2 diabetes). In fact, approximately 10% of type 2 diabetes cases are actually LADA and therefore do not respond to type 2 diabetes treatment, with which they are often misdiagnosed.
MODY type 2 diabetes
This type of diabetes is called Young-Onset Diabetes and usually appears before the age of 25. In this case, it is a monogenic disease, meaning it is caused by a mutation in a specific gene.
There are different types of MODY, each linked to a different gene. Generally, these genetic alterations affect the maturation of pancreatic beta cells and, consequently, insulin production. Between 1% and 2%, diabetic patients in Europe have this type of diabetes, although it is often misdiagnosed as type 1 or type 2 diabetes.
MODE 1
This type is caused by mutations in the HNF4A gene and represents the 10% type of MODY. When mutations occur in this gene, insulin production is reduced. These patients do not respond well to sulfonylureas, a drug used to treat diabetes by increasing insulin secretion from the beta cells of the pancreas.
MODE 2
This type is caused by mutations in the glucokinase (GK) gene. Between 30% and 50% of MODY diabetes cases are MODY 2, which is the most common type along with MODY 3. In this case, the mutations impair the body's ability to detect high glucose levels, hindering adequate insulin production. MODY 2 diabetes is considered mild, and only about 5% of patients experience complications. In fact, at the time of diagnosis, they usually present with elevated glucose levels but no other symptoms.
MODE 3
This type is caused by mutations in the HNF1A gene and accounts for MODY types 30% to 50%. In this case, patients have elevated glucose levels that increase over time, often leading to diabetic complications. The average age at diagnosis is 14 years. Many cases are mistakenly diagnosed as type 1 diabetes and treated with insulin when they typically respond well to sulfonylureas.
MODE 4
This type, which accounts for approximately 1% of MODY diabetes, is due to mutations in the PDX1 gene, which plays a key role in the development of the pancreas.
MODE 5
This other type is due to mutations in the HNF1B gene and accounts for 51% of MODY diabetes cases. In addition to all those listed, there are other, much less frequent types of MODY diabetes caused by different genes:
MODY6 type (NEUROD1 gene)
MODY 7 type (gen KLF11)
MODY 8 type (CEL gen)
MODY type 9 (PAX4 generation)
MODY type 10 (INS gene)
MODY type 11 (BLK gene)
MODY type 12 (ABCC8 gene)
MODY type 13 (gen KCNJ11)
Gestational diabetes
Gestational diabetes occurs in 101% of pregnant women and can affect fetal development and increase pregnancy-related risks. Its origin is multifactorial, meaning it depends on both genetics and the environment.
Although the hereditary factor had been known for some time, it was not until 2019 that the first specific gene directly involved in the development of gestational diabetes was identified: PAX8. This finding is the result of research work by scientists from the Institute of Medical and Molecular Genetics of La Paz together with the Andalusian Center for Molecular Biology and Regenerative Medicine-Cabimer, of the University of Seville.
Why does blood glucose tend to increase during pregnancy?
The normal physiological mechanisms of pregnancy lead to the production of human placental lactogen (HPL), also known as human chorionic somatomammotropin, a hormone whose function is to ensure that the baby receives an adequate supply of energy. To achieve this, it exerts the opposite effect of insulin, that is, it promotes the retention of glucose in the blood, which is why there is a greater likelihood of elevated glucose levels during pregnancy.
To detect pregnant women with abnormally high glucose levels, all pregnant women undergo screening tests between weeks 24 and 28. Gestational diabetes usually resolves after delivery.
secondary diabetes
Secondary diabetes results from external agents or other primary conditions, such as hemochromatosis or Cushing's disease. Secondary hyperglycemia can also be caused by the use of certain medications.
Can I prevent diabetes?
141% of the Spanish population suffers from diabetes, making it one of the most prevalent diseases. Diabetes is of great interest to the general public because many types can be prevented through lifestyle changes.
In this article, we have attempted to explain the hereditary nature of the different types of diabetes. Although genetic inheritance plays a significant role in the development of this disease, in most cases it results from a combination of genes, immunological factors, and environmental factors, making our lifestyle a useful tool in the prevention of some types of diabetes.
In other cases, genes play a determining role in the development of diabetes, as occurs in MODY type diabetes, and genetic testing is important for a correct diagnosis of the disease.
At Veritas, we strive to help convey the importance of genetics in the prevention and diagnosis of diseases. We hope we've helped you better understand this very common condition! If you'd like more information, contact us and resolves all your doubts.
Source: https://www.veritasint.com/blog/en/is-diabetes-hereditary/
