An unusually high incidence of homozygous MM in ankylosing spondylitis

Blood types of patients admitted to the Hadassah University Hospital with ankylosing spondylitis did not differ significantly from the expected percentages among the Israeli population, except for a very high incidence (92% to 100%) of homozygous MM. Among healthy controls the incidence of homozygous MM was found to be in line with accepted values.