SNP Shot: Genomic Insights

Ollier disease is a condition marked by the presence of numerous enchondromas. These are benign, non-cancerous cartilage tumors that grow inside the bones. While they frequently appear in the long bones of the arms and legs, particularly the hands and feet, they can also affect the skull, ribs, and spine. These enchondromas can lead to significant bone malformations, limb shortening, and an increased risk of fractures.

Although signs of Ollier disease can sometimes be noticed at birth, they usually become noticeable around age 5. The enchondromas develop near the ends of bones, where growth takes place, and usually stop forming after a person's growth ceases in early adulthood. The bone deformities associated with the disease can result in short stature and underdeveloped muscles.

While enchondromas in Ollier disease are initially benign, they carry a risk of becoming cancerous. Specifically, individuals with Ollier disease have an elevated risk of developing chondrosarcomas, a type of bone cancer, particularly in the skull. They are also at a higher risk for other cancers, such as ovarian or liver cancer.

Generally, people with Ollier disease have a normal life expectancy, and their intelligence remains unaffected. The degree of physical impairment varies depending on the individual's skeletal deformities; however, most individuals experience no major limitations in their daily activities.

Maffucci syndrome is a similar condition that also involves multiple enchondromas but is distinguished by the presence of hemangiomas, which are red or purplish skin growths composed of abnormal blood vessels.

Inheritance:

Ollier disease is not passed down through families. The genetic changes (mutations) responsible for the condition are somatic, meaning they arise during a person's lifetime. A somatic mutation occurs in a single cell, and as that cell divides, the mutation is passed on to its daughter cells. In Ollier disease, it's believed the mutation happens in a cell early in development, before birth. Only cells that originate from this affected cell carry the mutation, while the remaining cells of the body remain unaffected. This phenomenon is known as mosaicism.