Inflammatory Bowel Disease and T cell Lymphopenia in G6PC3 Deficiency
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G6PC3 deficiency presents as a complex and heterogeneous syndrome that classically associates severe congenital neutropenia with cardiac and urogenital developmental defects. Here we investigate the findings of T cell lymphopenia and inflammatory bowel disease in a child with G6PC3 deficiency due to compound heterozygous mutations in intron 3 (c.IVS3-1 G>A) and exon 6 (c.G778G/C; p.Gly260/Arg).
Histological examination was conducted on all biopsy specimens. Immunophenotyping and lymphocyte proliferation assays were performed. Immunoglobulin levels and vaccine responses were measured.
The patient showed persistent global T cell lymphopenia, with only 8 to 13 % of thymic naive CD31+CD45RA+ cells among CD4 T cells (normal range 27–60 %). Proliferation assays and vaccine responses were within normal limits. The gastrointestinal inflammatory lesions were very closely related to those of glycogen storage disease type 1b, with a Crohn’s-like appearance but without granuloma or increased cryptic abscesses. The gastrointestinal disease responded to infliximab therapy. These findings were associated with a polyclonal hypergammaglobuliemia G.
G6PC3 deficiency may present with inflammatory bowel disease and T cell lymphopenia. The diagnosis should thus be considered in a patient with chronic congenital neutropenia and gastrointestinal symptoms. Patients with confirmed disease should also undergo T cell phenotyping to rule out cellular immunodeficiency.
KeywordsG6PC3 congenital neutropenia inflammatory bowel disease lymphopenia G6PT thymic naive
Conflicts of interest
None of the authors has any potential financial conflict of interest related to this manuscript
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