It’s estimated that everyone carries between 5 and 10 genetic mutations in their DNA. While these mutations don’t always present obvious symptoms, it’s possible to pass them on to your children, even if you don’t have a family history of a particular disorder.
Whether or not your child is born with these genetic traits depends on inheritance factors, also known as genes. For each genetic trait, a child receives one gene from each parent. Although pregnancy is uncertain, learning about carrier genetics can help couples interested in starting a family determine their child’s risk of a genetic mutation.
Inheritance Factors That Cause Mutations
There are two different inheritance factors that can lead to the development of a genetic mutation: X-linked inheritance and autosomal recessive inheritance.
X-Linked Inheritance Disorders. X-linked inheritance disorders can be dominant or recessive.
- X-linked dominant disorders develop due to mutations of genes on the X chromosome. Females have two X chromosomes (XX), while males only have one (XY). For a female to develop an x-linked dominant disorder, a mutation in one of the two copies of the gene must occur. To affect a male, a mutation in the only copy of the gene is necessary. Because of this distinction, males are also more likely to experience severe symptoms associated with x-linked dominant disorders than their female counterparts.
- X-linked recessive disorders are also caused by mutations to genes on the X chromosome. However, because males only have one X chromosome (XY), just one mutation can cause a disorder. For an x-linked recessive disorder to affect a female, a mutation must be present in both copies of the gene (XX). This means males are also more likely to suffer from x-linked recessive disorders than females.
Autosomal Recessive Inheritance Disorders. Autosomal recessive inheritance disorders develop when a person inherits two separate genetic mutations, one from each parent. If both parents are carriers – meaning that their DNA has at least one genetic mutation – then their child has a 25% risk of having an autosomal recessive inheritance disorder. Unfortunately, many carriers don’t know they’re at risk. This is because autosomal recessive traits typically don’t present any obvious signs or symptoms. In addition, autosomal recessive disorders tend to skip generations.
Types of X-Linked Inheritance Disorders
There are a variety of X-linked inheritance disorders. Some of the most common are:
- Fragile X syndrome
- Red-Green Colorblindness
- Duchenne Muscular Dystrophy
- Becker’s Muscular Dystrophy
Types of Autosomal Recessive Inheritance Disorders
- Cystic Fibrosis
- Cycle Cell Anemia (also known as sickle cell disease)
- Tay-Sachs Disease
Testing and Learning More
If you’re thinking about starting a family, then you’re probably wondering whether or not your child is at risk of developing a genetic mutation. Genetic carrier testing provides a safe, effective means of answering this question. This screening procedure identifies between 3 and 110 hereditary disorders and involves a simple three-step process.
First, you visit your general practitioner or OB/GYN and have your blood drawn. Next, your sample is sent to a laboratory for further testing. A few weeks later, you visit your doctor for a follow-up appointment where your results are revealed. If it’s determined that you or your partner are a genetic carrier, then your doctor can answer any questions you have or refer you to a qualified genetic counselor.