Neurodevelopmental Outcome in Isolated Vermian Hypoplasia: A Single-Center Retrospective Cohort Study and Literature Review

Abstract

Vermian hypoplasia (VH) is characterized by reduced cerebellar vermis volume without significant hemispheric involvement. To date, data on long-term neurodevelopmental outcomes in isolated VH cases are limited, complicating prenatal counselling. This is single-center retrospective cohort study analyzing fetuses with posterior fossa abnormalities (PFA) diagnosed between 2010 and 2021. VH cases were confirmed through ultrasonography and fetal MRI, excluding non-isolated anomalies or ischemic/hemorrhagic etiologies. We collected data on Neurodevelopmental outcomes through chart review and structured interviews with the caregiver. We also provided a literature review summarizing prior research on VH outcomes. Out of 45 cases with (PFA), isolated VH was found in 15 children and was confirmed in 7 cases through fetal MRI. Among these patients, median gestational age at diagnosis was 22.5 weeks, with follow-ups extending to a median age of 6 years. Age-appropriate neurodevelopmental outcomes were normal or showed minimal deficits in 6/7 (70%). Literature review highlighted a wide outcome variability, partly due to varying diagnostic criteria and follow-up protocols. Long-term prognosis is influenced by various factors, including genetic testing and environmental support. In isolated VH, outcomes are generally favorable, though mild learning or motor coordination deficits may emerge. Broader normative biometrics and consistent neurodevelopmental evaluations are critical for improved prognostic precision. VH presents diagnostic and prognostic challenges due to variability in outcomes and limited longitudinal data. A multidisciplinary approach, including prenatal imaging, genetic testing, and structured follow-up, is essential for effective family counseling and developmental support. Prospective studies with larger cohorts are warranted to establish clearer guidelines.

Keywords: Isolated vermian hypoplasia; Neurodevelopmental outcome; Prenatal counselling; Prenatal diagnosis.