What Conditions Can Be Caused by Deletion Mutations?

Medically Reviewed on 2/1/2023
Deletion Mutations
Coping with a deletion mutation depends on the specific condition and symptoms caused.

In terms of genetics, deletion is a type of mutation that occurs when one or more nucleotides are lost from a section of DNA. Any number of nucleotides can be lost during a deletion, ranging from one nucleotide to an entire section of a chromosome.

Deletion mutations can cause a variety of serious genetic diseases or harmless mutations, depending on the size of the deletion or genes affected.

Five examples of deletion mutation

The following are five serious conditions that can be caused by deletion mutations:

  1. DiGeorge syndrome
    • Caused by the deletion of a portion of chromosome 22.
    • Characterized by immune system problems, heart defects, and abnormalities of the face and neck.
  2. Cri du chat syndrome
    • A result of the deletion of a portion of chromosome 5.
    • Characterized by a high-pitched cry (that sounds like a cat), developmental delays, intellectual disability, and physical abnormalities.
  3. Wolf-Hirschhorn syndrome
    • Caused due to the deletion of a portion of chromosome 4. 
    • Characterized by intellectual disability, seizures, and physical abnormalities, such as a small head and facial abnormalities.
  4. Prader-Willi syndrome
    • Caused by the deletion of a portion of chromosome 15.
    • Characterized by intellectual disability, difficulty feeding, and gaining weight in infancy and compulsive eating and obesity in later life.
  5. Angelman syndrome
    • Caused by the deletion of a portion of chromosome 15.
    • Characterized by severe intellectual disability, developmental delays, and problems with movement and balance.

What is a deletion mutation?

A deletion mutation is a type of genetic mutation that involves the removal of a portion of the genetic material. A deletion mutation in the DNA occurs when one or more nucleotides are removed from the DNA sequence. The genetic code is read by enzymes that produce proteins, and any change in the code can result in the loss of one or more amino acids from the protein. This can alter the function of the protein.

Deletion mutations can be large, involving the removal of hundreds or thousands of nucleotides, or they can be small, involving the removal of just a single nucleotide. 

Deletion mutations can have a variety of effects on an organism, ranging from benign to serious or even lethal.

What are the causes of deletion mutations?

Three factors that can cause deletion mutations include:

  1. Errors during DNA replication
    • DNA replication is the process by which cells produce copies of their genetic material to divide and produce new cells.
    • During this process, the DNA polymerase enzyme reads the DNA template and synthesizes a new strand of DNA by adding nucleotides to the growing strand.
    • Sometimes, the DNA polymerase enzyme may make a mistake and skip over a nucleotide or add the wrong nucleotide to the growing strand. If this happens, a deletion mutation can occur.
  2. Exposure to certain chemicals or radiations
    • Certain chemicals and radiations can damage DNA and cause mutations.
    • Chemicals such as alkylating agents, which are often used in chemotherapy to treat cancer, can cause deletions by adding alkyl groups to the DNA molecule.
    • Ionizing radiation, such as X-rays or UV radiation, can cause DNA damage and result in deletions.
  3. Damage to DNA caused by oxidative stress
    • Oxidative stress occurs when the body's cells produce too many reactive oxygen species, which can damage DNA, proteins, and other cellular components. This can result in the formation of DNA lesions, including deletions.

It is also important to note that spontaneous deletion mutations can occur due to other processes such as DNA repair mechanisms.

How to cope with a deletion mutation

The strategy to cope with a deletion mutation depends on the specific condition and symptoms that are caused by the mutation. There may not always be a cure for the condition; however, supportive care and treatments that can aid in managing the symptoms will help manage the disease, reducing symptoms and improving the quality of life.

Five general strategies that may help an individual cope with a deletion mutation include:

  1. Medical care
    • Seek medical care from a healthcare professional who is familiar with the specific condition caused by the deletion mutation. They can guide how to manage the condition and help identify any available treatments.
  2. Manage symptoms
    • Symptoms of specific conditions can be treated or managed well. For example, if the condition causes problems with feeding or nutrition, you may recommend a special diet or feeding plan.
  3. Rehabilitation
    • May be recommended to help improve physical, cognitive, or social skills. 
    • May include physical therapy, occupational therapy, speech therapy, or other types of therapy.
  4. Support groups
    • Joining a support group for people with the same condition can be a great way to connect with others who are experiencing similar challenges and learn about coping strategies and resources.
  5. Special resources
    • There may be a variety of resources available to help manage the condition, such as financial assistance, special education programs, or adaptive equipment. It can be helpful to research and take advantage of these resources.

Everyone is unique and what works for one person might not work for another. Working with a healthcare expert or other professional to choose the appropriate coping mechanisms for a deletion mutation may be beneficial.

Medically Reviewed on 2/1/2023
References
Image Source: iStock image

Deletion Mutation: https://biologydictionary.net/deletion-mutation/

Structural Abnormalities: Deletions (Cri du Chat) and Duplications (Pallister Killian) https://www.stanfordchildrens.org/en/topic/default?id=structural-abnormalities-deletions-cri-du-chat-and-duplications-pallister-killian-90-P02147