As of 2015, whether or not Paget's disease is hereditary is still being debated, according to Medscape. While familial links and external causes, such as viruses, have been suggested, neither case has been successfully proven.
Paget's disease is a condition in which a person's bone is reabsorbed and replaced with newer bone, according to Medscape. What follows next is a sharp increase in bone formation, which results in the bone becoming structurally weak and more prone to breaking or injury.
The first thought on how the disease was spread occurred in 1883, when a father-daughter pair reported the condition, states Medscape. Two years later, the disease was reported in a pair of siblings. This led early doctors to believe the disease was hereditary. However, later tests would show that only 40 percent of patients with the disease shared a familial history. Doctors have also suggested that the disease resides on a specific chromosome, but this was later proven not to be the case in many individuals with the disease.
Other doctors speculate that the disease is triggered by viral means, according to Medscape. Biopsies performed on individuals with Paget's disease have shown that their bodies have produced antigens against a specific type of virus, known as Paramyxoviridae viruses, which could suggest a link between the two. Such a link has yet to be proven.