SNP Shot: Genomic Insights

Hereditary multiple osteochondromas (HMO) is a genetic disorder characterized by the development of numerous non-cancerous bone growths called osteochondromas. Individuals with HMO exhibit varying numbers of these tumors, which can appear on different bones throughout the body. While not present at birth, most affected individuals (approximately 96%) will develop multiple osteochondromas by age 12. These tumors typically arise near the ends of long bones and on flat bones such as the hip and scapula.

The presence of multiple osteochondromas can interfere with normal bone development, leading to growth abnormalities in the arms, hands, and legs, and potentially resulting in short stature. Uneven limb lengths (limb length discrepancy) are common, as the effects on bone growth often differ between the left and right sides of the body. Osteochondromas can also cause bowing of the forearm or ankle, and hip dysplasia (abnormal hip joint development), which can lead to discomfort and difficulty walking. Additionally, the presence of these tumors may cause pain, restricted joint movement, and pressure on nearby nerves, blood vessels, the spinal cord, and surrounding tissues.

Although osteochondromas are generally benign, there is a risk of malignant transformation (becoming cancerous). Studies suggest that individuals with hereditary multiple osteochondromas have an estimated lifetime risk of developing a cancerous osteochondroma (sarcoma) ranging from 1 in 20 to 1 in 200.

Inheritance:

HMO follows an autosomal dominant inheritance pattern. This means that only one copy of a mutated gene is needed in each cell to cause the condition.