Immunodeficiency in a Child with Rapadilino Syndrome: A Case Report and Review of the Literature

Abstract

Rapadilino syndrome is a genetic disease characterized by a characteristic clinical tableau. It is caused by mutations in RECQL4 gene. Immunodeficiency is not described as a classical feature of the disease. We present a 2-year-old girl with Rapadilino syndrome with important lymphadenopathies and pneumonia due to disseminated Mycobacterium lentiflavum infection. An immunological work-up showed several unexpected abnormalities. Repeated blood samples showed severe lymphopenia. Immunophenotyping showed low T, B, and NK cells. No Treg cells were seen. T cell responses to stimulations were insufficient. The IL12/IL23 interferon gamma pathway was normal. Gamma globulin levels and vaccination responses were low. With this report, we aim to stress the importance of screening immunodeficiency in patients with RECQL4 mutations for immunodeficiency and the need to further research into its physiopathology.

Figure 1

CT scan showing mediastinal enlargement and bilateral infiltrates.

Figure 2

Radiosensitivity assay. Clonogenic survival assays with primary skin were performed as described in Noordzij et al., Blood 2003 [5]. In short, primary skin fibroblasts in exponential growth were trypsinized, and 1000–2,000 cells (10,000–20,000 cells for the highest doses) were seeded into 10 cm plastic dishes (2 dishes per dose) and irradiated at room temperature with 0, 1,2,4 or 6 Gy. After 12–14 days, the cells were rinsed with 0.9% NaCl and stained with 0.25% methylene blue for survival assessment. Two independent survival experiments were performed.