Stable transmission of an unbalanced chromosome 21 derived from chromoanasynthesis in a patient with a SYNGAP1 likely pathogenic variant

BackgroundComplex genomic structural variations, involving chromoanagenesis, have been implicated in multiple congenital anomalies and abnormal neurodevelopment. Familial inheritance of complex chromosomal structural alteration resulting from germline chromoanagenesis-type mechanisms are limited.Case presentationWe report a two-year eleven-month old male presenting with epilepsy, ataxia and dysmorphic features of unknown etiology. Chromosomal …