Linker for activation of T cells (LAT) mutation leading to CNS neuroimmunological disorder with treatment response to abatacept

Abstract

Background

Linker for activation of T cells (LAT) is a scaffolding protein that couples T-cell receptors (TCRs) to downstream signaling pathways and plays a critical role in TCR-mediated signaling and thymocyte development. LAT loss-of-function mutations have been reported in severe combined immunodeficiencies (SCID). Mutations in the LAT gene resulting in central nervous system (CNS) disorders have not previously been reported.

Case presentation

We report a case of a unique and recurrent neuroinflammatory disorder in a patient with a LAT gene mutation and a prior history of immune deficiency and autoimmunity.

Case report

Patient with LAT heterozygous missense mutation presented with a CNS demyelinating inflammatory disorder with similar clinical, pathological and radiographic features to patients with heterozygous mutations in immune checkpoint inhibitor cytotoxic T-lymphocyte associated protein 4 (CTLA4). CNS inflammatory disorder improved with treatment with CTLA4-IgG₁ fusion protein abatacept. This is the first reported case of CNS inflammation associated with a LAT gene mutation.

Conclusions

LAT and CTLA4 mutations appear to result in overlapping phenotypes and patients with mutations in LAT or proteins involved in LAT signaling may exhibit similar presentations and responses to immune checkpoint inhibitors.