Two different presentations of de novo variants of CSNK2B: two case reports

BACKGROUND: Poirier–Bienvenu neurodevelopmental syndrome is a neurologic disorder caused by mutations in the CSNK2B gene. It is mostly characterized by early-onset seizures, hypotonia, and mild dysmorphic features. Craniodigital syndrome is a recently described disorder also related to CSNK2B, with a single report in the literature. OBJECTIVE: To report two unrelated cases of children harboring CSNK2B variants (NM_001320.6) who presented with distinct diseases. CASE REPORT: Case 1 is a 7-month-old, Caucasian, female patient with chief complaints of severe hypotonia and drug-refractory myoclonic epilepsy, with a likely pathogenic de novo variant c.494A>G (p.His165Arg). Case 2 is a 5-year-old male, Latino patient with craniodigital intellectual disability syndrome subjacent to a de novo, likely pathogenic variant c.94G>T (p.Asp32Tyr). His dysmorphic features included facial dysmorphisms, supernumerary nipples, and left-hand postaxial polydactyly. CONCLUSION: This report suggest that the CSNK2B gene may be involved in the physiopathology of neurodevelopmental disorders and variable dysmorphic features.