Immunodeficiency, Common Variable, 6
A number sign (#) is used with this entry because of evidence that this form of common variable immunodeficiency, referred to here as CVID6, is caused by homozygous mutation in the CD81 gene (186845) on chromosome 11p. One such patient has been reported.
For a general description and a discussion of genetic heterogeneity of common variable immunodeficiency, see CVID1 (607594).
Clinical FeaturesVan Zelm et al. (2010) reported a 6-year-old Moroccan girl, born of consanguineous parents, who had recurrent respiratory tract infections in the first 2 years of life. At age 3.5 years, she developed an acute glomerulonephritis with proteinuria, a purpuric rash, and arthralgias, associated with deposition of IgA and C3 (120700) and resulting in renal failure. She also had hepatomegaly and thrombocytopenia associated with antiplatelet antibodies. Laboratory studies showed hypogammaglobulinemia with decreased IgG, low to normal IgA, and normal IgM. There was no antibody response to either tetanus or pneumococcal antigens. Flow cytometric studies showed normal levels of B, T, and NK cells, but B cells lacked CD19 (107265) and CD81 surface expression, and there were decreased numbers of memory B cells. Van Zelm et al. (2010) noted the phenotypic similarities to patients with CD19 defects resulting in CVID3 (613493).
Molecular GeneticsIn a Moroccan girl with common variable immunodeficiency, van Zelm et al. (2010) identified a homozygous mutation in the CD81 gene (186845.0001).