Hemophagocytic lymphohistiocytosis (HLH) occurs in the primary form (genetic or familial) or secondary form (acquired). The familial form of HLH (FHL) is a potentially fatal autosomal recessive disorder that occurs because of constitutional defects in cell-mediated cytotoxicity. Here, we report a fatal neonatal case of type 2 FHL (FHL2) that involved a novel frameshift mutation. Clinically, the newborn presented with...

A retropharyngeal abscess is a rare disease entity in young infants but can develop after nasopharyngeal viral infection. Group B Streptococcus and Staphylococcus aureus are the most common pathogens in young infants, however, Mycobacterium tuberculosis is very rare. We report the case of retropharyngeal abscess and coinfection with S. aureus and M. tuberculosis in a very young infant presenting with...

Nonketotic hyperglycinemia (NKH) is a rare inborn error of amino acid metabolism. A defect in the glycine cleavage enzyme system results in highly elevated concentrations of glycine in the plasma, urine, cerebrospinal fluid, and brain, resulting in glycine-induced encephalopathy and neuropathy. The prevalence of NKH in Korea is very low, and no reports of surviving patients are available, given the...