Single-gene genetic disorders, also known as Mendelian disorders, are a category of genetic conditions caused by mutations in a single gene.
These disorders can have significant impacts on an individual’s health and well-being.
Today, we will explore single-gene genetic disorders and some common examples.
Understanding Single-Gene Disorders
Single-gene disorders result from changes or mutations in a specific gene’s DNA sequence. These mutations can alter the gene’s function, leading to the production of abnormal proteins or a complete absence of the protein it codes for. The inheritance pattern for these disorders can be classified into two main types:
1. Autosomal Dominant Disorders
In autosomal dominant disorders, a single copy of the mutated gene from one parent is sufficient to cause the disorder. If one parent carries the mutant gene, there is a 50% chance of passing it on to their offspring. Examples of autosomal dominant disorders include Huntington’s disease and Marfan syndrome.
2. Autosomal Recessive Disorders
Autosomal recessive disorders require two copies of the mutated gene, one from each parent, for the disorder to manifest. Carrier parents (heterozygous) do not typically show symptoms but can pass the mutated gene to their children. When both parents are carriers, there is a 25% chance that their child will inherit two copies of the mutated gene and develop the disorder. Examples of autosomal recessive disorders include cystic fibrosis and sickle cell anemia.
Common Examples of Single-Gene Disorders
Cystic Fibrosis
Cystic fibrosis is an autosomal recessive disorder that primarily affects the respiratory and digestive systems. It leads to the production of thick and sticky mucus, causing breathing difficulties, lung infections, and digestive problems.
Sickle Cell Anemia
Sickle cell anemia is also an autosomal recessive disorder characterized by abnormally shaped red blood cells. These cells can block blood flow, leading to pain, anemia, and organ damage.
Huntington’s Disease
Huntington’s disease is an autosomal dominant disorder that affects the nervous system. It causes progressive motor dysfunction, cognitive decline, and psychiatric symptoms.
Marfan Syndrome
Marfan syndrome is an autosomal dominant disorder that affects connective tissue. It can lead to tall stature, joint hypermobility, heart valve problems, and other issues.
Single-gene genetic disorders are a diverse group of conditions caused by mutations in a single gene. Understanding their inheritance patterns is crucial for genetic counseling and family planning.
Advances in genetic research have paved the way for improved diagnosis and potential treatments for these disorders, offering hope for affected individuals and their families.
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