Expanding the clinical phenotype and genetic spectrum of PURA-related neurodevelopmental disorders

BACKGROUND PURA-related neurodevelopmental disorders (PURA-NDDs) include 5q31.3 deletion syndrome and PURA syndrome. PURA-NDDs are characterized by neonatal hypotonia, moderate to severe global developmental delay/intellectual disability (GDD/ID), facial dysmorphism, epileptic seizures, nonepileptic movement disorders, and ophthalmological problems. PURA-NDDs have recently been identified and underestimated in neurodevelopmental cohorts, but their diagnosis is still challenging. METHODS We retrospectively reviewed the clinical characteristics, genetic spectrum, and diagnostic journey of patients with PURA-NDDs. RESULTS We report 2 patients with 5q31.3 microdeletion and 5 with PURA pathogenic variants. They demonstrated hypotonia (7/7, 100%), feeding difficulties (4/5, 80%), and respiratory problems (4/7, 57%) in the neonatal period. All of them had severe GDD/ID and could not achieve independent walking and verbal responses. Distinctive facial features of open-tented upper vermilion, long philtrum, and anteverted nares and poor visual fixation and tracking with or without nystagmus were most commonly found (5/7, 71.4%). There were no significant differences in clinical phenotypes between 5q31.3 microdeletion syndrome and PURA syndrome. PURA-NDDs need to be considered as a differential diagnosis in individuals who show severe hypotonia, including feeding difficulties since birth and severe developmental retardation with distinctive facial and ophthalmological features. CONCLUSIONS Our data expands the phenotypic and genetic spectrum of PURA-NDD. Next-generation sequencing methods based on the detailed phenotypic evaluation would shorten the diagnostic delay and would help this rare disorder become a recognizable cause of neurodevelopmental delay.