Minegishi et al. (1999) reported a boy with immunodeficiency associated with absent pre-B and mature B cells, but normal numbers of pro-B cells. The defect thus occurred at the pro-B to pre-B cell transition stage. The patient had ... Minegishi et al. (1999) reported a boy with immunodeficiency associated with absent pre-B and mature B cells, but normal numbers of pro-B cells. The defect thus occurred at the pro-B to pre-B cell transition stage. The patient had developed recurrent otitis at 8 months of age; after 2 episodes of pneumonia, he was evaluated for immunodeficiency at 16 months of age. At that time, he had no detectable serum IgG, IgM, or IgA, and he had less than 1% B cells in the peripheral circulation. He was started on gammaglobulin replacement, and between 2 and 20 years of age he did well except for chronic otitis and sinusitis, hepatitis C acquired from intravenous gammaglobulin, and an episode of protein-losing enteropathy in adolescence. An older brother developed recurrent otitis at 6 months of age and died at 16 months of age of pseudomonas sepsis and neutropenia.
In a patient with agammaglobulinemia-4, Minegishi et al. (1999) identified a homozygous splice defect in the BLNK gene (604515.0001). The patient's mother and father, who were heterozygous for the mutation, were healthy and had normal concentrations of serum ... In a patient with agammaglobulinemia-4, Minegishi et al. (1999) identified a homozygous splice defect in the BLNK gene (604515.0001). The patient's mother and father, who were heterozygous for the mutation, were healthy and had normal concentrations of serum immunoglobulins and normal numbers of B cells. The findings indicated that BLNK plays a critical role in orchestrating the pro-B cell to pre-B cell transition.