Genetic Diseases and Family Planning
Genetic diseases encompass a vast group of disorders that occur due to alterations or mutations in genes. These conditions can be inherited from parents or result from spontaneous mutations. Understanding genetic diseases is crucial to protect our own health and that of future generations.
Family planning is a crucial time in the lives of many couples. In addition to career considerations, economic stability, and child welfare, genetics is gaining more and more importance at this stage.
Whole Genome Sequencing (WGS) analysis has become a valuable resource in family planning because it can help identify and prevent inherited diseases. Let's see why this technology is so important.
The cause of hereditary diseases
The rules of transmission of inherited diseases between generations are very precise and can be divided into:
- Multifactorial diseases, that is caused by the complementary effect of genetic and environmental factors, such as lifestyle, smoking, diet, radiation and many other variables that depend on individual behaviour. For example: hypertension, diabetes, celiac disease, heart disease, etc;
- Chromosomal abnormality diseases, due to an abnormality in the number or structure of chromosomes;
- Monogenic diseases, that is caused by the alteration of a single gene on a single chromosome. We all carry many genetic mutations, but only a few are harmful and cause disease.
Transmission of hereditary diseases
The modes of transmission follow Mendel's laws and fall into four major groups:
- Autosomal Dominant involves genes that are hosted by autosomes, that is, non-sex chromosomes. In children who have inherited an autosomal dominant disease, one normal copy of the gene is present while the other copy is mutated. A parent who carries a mutated copy of one of the genes is himself or herself sick, and with each pregnancy has a 50% risk of having a sick child, regardless of the sex of the unborn child.
- Autosomal Recessive, in this case the diseases occur only in people who have inherited two mutated copies of a gene (i.e., one from the mother and one from the father). The term "recessive" means that the alteration of only one of the two gene copies is not sufficient to cause the disease so both copies of the genes must be mutated for the disease to develop. In this case the parents are called healthy carriers, in fact they are not sick but carry only one copy of the altered gene. Two healthy carriers who want to have children have, with each pregnancy, a 25% chance of having a sick child. The probability is independent of the sex of the unborn child.
- Linked To Chromosome X Recessive, in this case if a gene located on the X chromosome is mutated it causes the disease only if the alteration is not compensated by the presence of a normal copy of the same gene on the other X chromosome. This means that mutations in genes located on the X chromosome cause disease only in males because they possess only one X chromosome. Women who have a mutated gene on the X chromosome are referred to as healthy carriers because, with each pregnancy, they have a 50% chance of passing on the X chromosome containing the mutated gene to both male sons and female daughters. The male child who has inherited from his mother the X chromosome with the mutated gene will be sick because the altered function of the gene cannot be compensated by any normal copy of the same gene (the male has only one X chromosome and one Y chromosome). The female daughter who inherited from her mother the X chromosome with the mutated gene will, like her mother, become a healthy carrier since the mutation of the gene will be "compensated" by the normal copy of the same gene located on the second X chromosome. Much rarer is the situation in which a sick father can pass on the X chromosome with the mutated gene to his offspring. In this case, male offspring will never be at risk because they may receive only the Y chromosome from their father. The X chromosome with the mutated gene can only be passed on to female daughters who, in 100% of cases, will be healthy carriers but may in turn pass it on to their male offspring.
- Linked To Dominant X Chromosome, in this case the diseases are extremely rare, for example, Alport syndrome. If a female inherits a healthy X chromosome and a mutated X chromosome, the altered gene has the upper hand over the healthy one and thus the disease occurs. Diseased mothers have a 50% chance, with each pregnancy, of giving birth to a sick son or daughter. Sick fathers, on the other hand, have a 50% chance, with each pregnancy, of giving birth to a sick daughter while they will never give birth to a sick male child, as the male transmits the Y chromosome and not the X chromosome.
What Are the Most Common Hereditary Genetic Diseases?
While there are thousands of known genetic diseases, some are more common and well-studied. Here are some of the most prevalent genetic diseases:
- Cystic Fibrosis: A hereditary disease affecting the respiratory and digestive systems. Mutations in the CFTR gene lead to excessive mucus production.
- Thalassemia: A group of inherited blood disorders that affect hemoglobin production, resulting in anemia and other complications.
- Down Syndrome: Caused by an extra copy of chromosome 21, this condition is associated with intellectual disability, growth delays, and recognizable physical features.
- Duchenne Muscular Dystrophy: A muscle disorder causing progressive weakness and loss of function.
- Sickle Cell Anemia: A hereditary blood disorder characterized by deformed red blood cells, which can cause vascular blockages and severe symptoms.
Whole Genome Sequencing analysis and Carrier Screening Panel
Knowing the genetic risk enables couples to make informed family planning decisions. Whole genome sequencing analysis is the only test that analyzes 100% of your DNA.
If both parents performed this test they can identify any genetic variations, mutations, or abnormalities that may be associated with inherited diseases.
This information is critical in determining whether both parents carry mutations in a specific gene, increasing the risk of passing the disease on to their children.
Before embarking on the road to parenthood, it is essential to understand the genetic risk that could affect the health of future children.
Dante Labs' MyGenome Sequencing Test and Carrier Screening Panel provide a comprehensive overview of the genetic makeup of both parents, identifying potential carriers of genetic mutations that could be passed onto offspring.
After DNA testing by both parents, genetic counseling can be booked. Genetic counseling is a vital support service for couples planning to have children or facing challenges related to genetics in their family.
An experienced genetic counselor can review family history, assess risk for inherited diseases, and identify potential genetic problems that could affect future children. In addition, the counselor can support parents in making informed decisions to address any identified genetic problems. The counselor also provides emotional and educational support, both in understanding the test information and in managing the emotions associated with making decisions based on accurate data and information.
Understanding the genetic factors that influence family planning is essential for responsible parenthood. Genetic diseases can significantly impact future generations' health and well-being, making it crucial for couples to be well-informed and proactive.
MyGenome Sequencing (WGS) analysis and Carrier Screening Panel offer a comprehensive view of an individual's DNA, helping couples identify potential genetic risks. By both parents undergoing WGS, they can assess the risk of passing on inherited diseases to their children, allowing for informed family planning decisions.
Genetic counseling plays a crucial role in this process, providing support and guidance. Genetic counselors help couples interpret test results, assess family histories, and make informed choices based on accurate information.
In summary, integrating genetic testing and counseling into family planning empowers couples to make responsible decisions for the health of their future generations, ensuring a brighter and healthier future.