Abstract
Severe combined immunodeficiency (SCID) is an extremely rare disease caused by a disruption in the forkhead box N1 (FOXN1) gene, with an incidence of <1 per 1 000 000 live births. We report a boy aged 4 months who presented with a history of fever for 3 weeks and enlarged lymph nodes. The fever was associated with dry cough and runny nose. On physical examination, we noted oral thrush, generalised lymphadenopathy, nail dystrophy and alopecia. Flow cytometry of lymph node biopsy showed high-grade B-cell lymphoma. In addition, Epstein-Barr virus (EBV) infection was documented by PCR. The diagnosis of SCID was made by genetic testing, which revealed a homozygous variant of the FOXN1 gene. The variant was confirmed with Sanger sequencing. Management of EBV infection and lymphoma was initiated; unfortunately, the patient passed away on day 45 of hospitalisation.