Novel RNASET2 Pathogenic Variants in an East Asian Child with Delayed Psychomotor Development.

Introduction: RNASET2 mutation has been reported in patients with cystic leukoencephalopathy without megalencephaly and the Aicardi-Goutieres syndrome. Both disorders are Mendelian mimics of congenital cytomegalovirus infection with overlapping features, including leukoencephalopathy, white matter alterations, intracranial calcification, delayed psychomotor development, intelligence disability and seizures. Only eight families with RNASET2 mutation have been previously reported. Methods: Whole exome sequencing was performed and copy number variants were described by read-depth strategy. Results: We identified a novel nonsense variant c.128G>A (p. W43*) and a 430 Kb 6q27 microdeletion encompassing RNASET2. Our patient did not show anterior temporal lobe subcortical cysts, hearing loss, dystonia or extra-neurological features. Conclusion: Our results provided further genetic and phenotypic information of RNASET2 mutation in Chinese patients and highlighted the importance for physicians to consider RNASET2-related disorders when diagnosing patients with congenital brain infection-like phenotypes.