Of the four cases reported, compound heterozygous mutation in TRNT1 (c.1213G>A/c.1057-7C>G) was identified in one child, expanding the repertoire of phenotypes associated with TRNT1. In addition to panniculitis, this patient also exhibited periodic febrile illness, chronic microcytosis and B cell deficiency, but no other clinical features typically seen in SIFD. Here, TRNT1 is linked to B cell deficiency.