Ring chromosome 18 syndrome

Other Names: 

Ring 18; Ring chromosome 18

Summary

Ring chromosome 18 is a rare chromosome abnormality in which the ends (arms) of chromosome 18 join together to form a ring shape. When a ring chromosome forms, genetic material can be lost from either arm or both arms, causing various signs and symptoms. While most people with Ring chromosome 18 have the ring chromosome in all of their body cells, some people also have some body cells with normal chromosomes (this is called mosaicism). People with Ring chromosome 18 mosaicism may have milder symptoms. Depending on the amount of genetic material lost and which genes are involved, signs and symptoms that may be present in a person with Ring chromosome 18 include ear and hearing abnormalities, abnormally-developed feet or hands, genital abnormalities in males, an increased risk to develop juvenile rheumatoid arthritis, holoprosencephaly, developmental delays, learning difficulties, short stature, and/or various birth defects. Ring chromosome 18 usually occurs sporadically (by chance) during the formation of egg or sperm cells or shortly after the egg and sperm join together. Occasionally, it is inherited from a parent (typically the mother). A chromosome test of the parents can help determine whether it was inherited and whether future children have an increased chance to have a chromosome abnormality.

About Ring chromosome 18 syndrome

Many rare diseases have limited information. Currently, GARD aims to provide the following information for this disease:

• Population Estimate:Fewer than 1,000 people in the U.S. have thisdisease.
• Symptoms:May start to appear during Pregnancy, at Birth, and as an Infant.
• Cause:This disease is caused by changes to the number or structure of a person’s chromosomes.
• Organizations:Patient organizations are available to help find a specialist, or advocacy and support for this specific disease.
• Categories:Birth Defects Genetic Diseases

Genetic Mutations

Ring chromosome 18 syndrome is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when parents pass them down to their children, or they may occur randomly when cells are dividing. Genetic mutations may also result from contracted viruses, environmental factors, such as UV radiation from sunlight exposure, or a combination of any of these. Learn more about genetic diseases from the National Library of Medicine (NLM).

If you suspect you may have this disease, you may want to start collecting your family health history. Information such as other family members who have had similar symptoms, when their/your symptoms first appeared, or exposures to any potential disease-causing environmental factors should be discussed with your medical team. This tool from the Surgeon General can help you collect your family health history.

When Do Symptoms of Ring chromosome 18 syndrome Begin?

Symptoms of this disease may start to appear during Pregnancy, at Birth, and as an Infant.

The age symptoms may begin to appear differs between diseases. Symptoms may begin in a single age range, or during several age ranges. The symptoms of some diseases may begin at any age. Knowing when symptoms may have appeared can help medical providers find the correct diagnosis.