Agammaglobulinemia 7, Mutation in PIK3R1 D81.4

Autosomal recessive agammaglobulinemia-7 (AGM7), a primary immunodeficiency syndrome, is caused by a homozygous mutation in the PIK3R1 gene (171833) on chromosome 5q13.

De la Morena et al (1995) reported on a 6-month-old girl of Chinese and Peruvian Indian descent who presented with interstitial pneumonia and gastroenteritis at 3.5 months of age. Laboratory tests showed agammaglobulinemia, neutropenia, and deficiency of mature B cells in peripheral blood and bone marrow. Lymph nodes showed deficiency of B cells, plasma cells, and germinal center formation. T cells and T cell function were normal. Laboratory data suggested blockage at an earlier stage of B-cell development than in the X-linked form of agammaglobulinemia (300755); a defect in the BTK gene (300300) was excluded.

Conley et al. (2012) reported the follow-up meanwhile of 19-year-old patienin published by de la Morena et al. (1995). As a teenager, she developed erythema nodosum, juvenile idiopathic arthritis, and recurrent Campylobacter infections and inflammatory bowel disease. Family history included two older brothers and two maternal uncles who died of acute infections between the ages of 9 and 18 months.

1. Conley ME et al (2012) Agammaglobulinemia and absent B lineage cells in a patient lacking the p85-alpha subunit of PI3K. J Exp Med 209: 463-470.

2. de la Morena M et al (1995) Predominance of sterile immunoglobulin transcripts in a female phenotypically resembling Bruton's agammaglobulinemia. Europ J Immun 25: 809-815.