Background: Familial hemophagocytic lymphohistiocytosis (FHL) onset in the fetal and neonatal periods is sporadic, and infants are susceptible to intrauterine death. Early and accurate diagnosis and treatment are the keys to preventing complications and death in FHL patients due to the complex and diverse clinical manifestations of the disease.
Methods: We report a rare case of a preterm infant with a low birth weight of 2,010 g and a gestational age of 32 + 4 weeks who presented with a leaky syndrome similar to sepsis after birth. Anti-infective, other support, and symptomatic treatments were not effective. Bone marrow examination results on day 13 suggested hemophago-cytosis.
Results: Various compound heterozygous UNC13D genes were found by exome sequencing, which confirmed the diagnosis of FHL type 3. Genetic variants of this locus have never been reported in the literature.
Conclusions: Neonatal onset FHL is challenging to diagnose, especially in premature infants. It is necessary to complete exome sequencing if the patient has no apparent pathogen infection or effective treatment.