Lipopolysaccharide Responsive Beige-like Anchor Protein Deficiency in a Patient with Autoimmune Lymphoproliferative Syndrome-like Disease Phenotype: A Case Report and Literature Review.

LPS-responsive beige-like anchor protein (LRBA) deficiency is a primary immunodeficiency caused by a mutation in the LRBA gene. Affected individuals present with a variety of clinical symptoms including hypogammaglobulinemia, recurrent infections, splenomegaly, hepatomegaly, and autoimmune cytopenias. Except for hypogammaglobulinemia, the remaining features resemble autoimmune lymphoproliferative syndrome (ALPS). Here, we report the case of a 14-year-old boy with the ALPS phenotype, eventually diagnosed with LRBA deficiency. He presented with lymphadenopathy and hepatosplenomegaly, along with autoimmune cytopenia. Due to recurrent infections and worsening gastrointestinal symptoms, whole-exome sequencing was conducted and revealed a novel homozygous pathogenic variant in the LRBA gene (c.534del; p.9Asp179IIef*16). The patient recently suffered from clinical deterioration due to SARS-COV-2 which appears to have triggered an acute worsening of his existing Cytomegalovirus colitis leading to an eventual demise. A literature search for reported LRBA deficient patients with ALPS-like phenotype revealed 11 patients. The most common clinical presentations in LRBA patients with ALPS-like phenotype included autoimmunity (100%), splenomegaly (91%), lymphadenopathy (36.4%), and respiratory tract infections (63.6%). LRBA deficiency is unique in the fact that it encompasses immune deficiency, autoimmunity, and lymphoproliferation. In children with multiple symptoms related to these domains, a genetic diagnosis is necessary to ensure tailored and precise medical therapy.