These patients have low IgM (less than 30 mg/dl in adults, less than 20 mg/dl in children) with recurrent infections that are often severe. There are variable antibody responses. Some patients are asymptomatic. This disease may be clinically similar to CVID though it should not be referred to by that name. It is important to note that IgM deficiency is also seen commonly in DOCK8 deficiency, typically in association with normal IgG and elevated IgE.