Agammaglobulinemia 6, Mutation in CD79B D80,0

Agammaglobulinemia 6, also known as AGM6, is caused by a homozygous mutation in the CD79B gene (147245) on chromosome 17q23.

Dobbs et al (2007) reported on a 15-year-old female patient of Georgian descent who suffered from recurrent infections, hypogammaglobulinemia. The patient was healthy before her period of infections until 5 months of age. At 15 months of age, she was evaluated for persistent cough and pneumonia. Detectable was panhypogammaglobulinemia. B cells <1%. The patient was initially treated with intravenous gamma globulin. At 3 and 10 years of age, she was treated for pneumonia. At 15 years of age, she was doing well on subcutaneous gamma globulin. She grew and developed normally and showed no signs of persistent infection. Flow cytometric analysis showed that the patient had a significant deficit of IgM-expressing B cells. Evidence was a homozygous mutation (G137S; 147245.0001) in the CD79B gene.

Ferrari et al (2007) reported a 20-year-old Italian man with agammaglobulinemia. He was first hospitalized at 8 months of age with Salmonella enteritis. Immunologic examination revealed marked hypogammaglobulinemia with low IgG and undetectable IgA and IgM and the absence of CD19-positive cells in the periphery. T and NK cell counts were normal, and T cell function was normal.

1. Dobbs AK et al (2007) Cutting edge: a hypomorphic mutation in Ig-beta (CD79b) in a patient with immunodeficiency and a leaky defect in B cell development. J Immun 179: 2055-2059.
2. Ferrari S et al (2007) Mutations of the Ig-beta gene cause agammaglobulinemia in man. J Exp Med 204: 2047-2051.
3. Takeuchi T et al.(2017) MYD88, CD79B, and CARD11 gene mutations in CD5-positive diffuse large B-cell lymphoma. Cancer 123:1166-1173.