Unravelling the diagnostic dilemma – A case series of radiologically diagnosed pontocerebellar hypoplasia.

Objectives: Pontocerebellar hypoplasia (PCH) are a group of neurogenetic disorders characterized by severe hypoplasia of cerebellum and pons, having a prenatal onset and postnatal progression. Its imaging pattern mimics many neurogenetic conditions so far not included as PCH. We reviewed clinical and radiological features of prenatal and postnatal cases suspected with PCH to discuss diagnostic dilemma and differential diagnosis.

Methods: All patients visiting Neurogenetic clinic from January 2021 to March 2022 with prenatal or postnatal neuroimaging of hypoplasia or atrophy of the cerebellum and pons, and/or a genetic diagnosis of PCH were included in the study. Their clinical details and neuroimaging were reviewed. Genetic data when available was analyzed with phenotype.

Results: Radiological criteria / Genetic diagnosis of PCH was fulfilled by 10 patients. Antenatal suspicion on fetal neurosonogram was made in 4 cases. Amongst them 1 was aborted and 3 who delivered expired within 1st month. They presented with birth asphyxia, seizures, dysmorphism and 2 also had arthrogryposis. Amongst postnatally suspected cases, neonatal presentation with birth asphyxia and dysmorphism was noted in 1, rest presented in infancy with global developmental delay and seizures. Microcephaly and visual abnormalities were other common features. On MRI all showed variable Corpus callosum and white matter abnormalities, 2 had Heterotopia. All 6 of them were on follow up during the study.

Conclusion: Clinical suspicion and accurate radioanalysis is important for early genetic confirmation and diagnosis of PCH. With expansion of the phenotype-genotype to the existing PCH classification, molecular testing is mainstay for definitive diagnosis.
Keywords: Pontocerebellar hypoplasia, PCH, Fetal, neurogenetic