Accelerated phase development in a late-onset adolescent Chediak-Higashi syndrome patient caused by compound novel LYST mutations in the setting of SARS-CoV-2 infection.

Chediak-Higashi syndrome (CHS) is a rare autosomal recessive genetic disorder characterized by severe immunodeficiency, albinism and coagulation deficiency. Mostly diagnosed in early childhood, this devastating condition is associated with lysosomal abnormalities attributed to the absence or impaired function of lysosomal trafficking regulator caused by mutations in the CHS1/LYST gene. In current study, we report a case of late-onset CHS caused by two novel compound heterozygous CHS1/LYST mutations: c.8407C > T, leading to early termination of translation at residue Gln2803 (p. Gln2803Ter), and a small deletion c. 4020_4031del, resulting in an in-frame deletion of three amino acid residues (p. Asp1343_Val1346del). Both variants retain a large part of the CHS/LYST protein, particularly p. Asp1343_Val1346del, which preserves critical functional BEACH and WD40 domains in the C terminal, potentially maintaining residual activity and alleviating patient symptoms. The timeline of SARS-CoV-2 infection and rapid symptom progression suggests that the viral infection may have trigger the accelerated phase development leading to a poor prognosis.