Below is an instruction from Human. Write a response.
    ### Instruction:
    How many people are affected by SOST-related sclerosing bone dysplasia ?
    ### Response:
    SOST-related sclerosing bone dysplasia is a rare condition; its exact prevalence is unknown.  Approximately 100 individuals with sclerosteosis have been reported in the scientific literature. Sclerosteosis is most common in the Afrikaner population of South Africa.
    