“…Studies in these populations performed in the late 1970s to early 1980s report a prevalence range from 1.2 to 39.2 per 100,000 people and an incidence range of 0.4 to 2.6 per 100,000 people per year. [4][5][6][7][8] In addition, a population-based study performed in Utah in 1992 documented a prevalence of 11.2 per 100,000 people and an incidence of 0.98 per 100,000 people per year, and both rates are comparable to studies performed in Europe. 8 Because the population of Utah has a high proportion of people with Northern European ancestry, the concordance of this finding with previous studies is not surprising.…”