Prenatal diagnosis of pontocerebellar hypoplasia with postnatal follow-up

ObjectiveTo describe the MR features enabling prenatal diagnosis of pontocerebellar hypoplasia (PCH).MethodThis was a retrospective single monocentre study. The inclusion criteria were decreased cerebellar biometry on dedicated neurosonography and available fetal Magnetic Resonance Imaging (MRI) with PCH diagnosis later confirmed either genetically or clinically on post-natal MRI or by autopsy. The exclusion criteria were non-available MRI and sonographic features suggestive of a known genetic or other pathologic diagnosis. The collected data were biometric or morphological imaging parameters, clinical outcome, termination of pregnancy (TOP), pathological findings and genetic analysis (karyotyping, chromosomal microarray, DNA sequencing targeted or exome). PCH was classified as classic, non-classic, chromosomal, or unknown type.ResultsForty-two fetuses were diagnosed with PCH, of which 27 were referred for decreased transverse cerebellar diameter at screening ultrasound. Neurosonography and fetal MRI were performed at a mean gestational age of 29 + 4 and 31 + 0 weeks, respectively. Termination of pregnancy occurred. Pregnancy was terminated in 24 cases. Neuropathological examination confirmed the diagnosis in 24 cases and genetic testing identified abnormalities in 29 cases (28 families, 14 chromosomal anomaly). Classic PCH is associated with pontine atrophy and small MR measurements decreasing with advancing gestation.ConclusionThis is the first large series of prenatally diagnosed PCHs. Our study shows the essential contribution of fetal MRI to the prenatal diagnosis of PCH. Classic PCHs are particularly severe and are associated with certain MR features. What is already known about this topic?Pontocerebellar hypoplasia (PCH) is a very rare disorder usually diagnosed after birth.PCH is associated with severe psychomotor delay or even early death in childhood.The onset of PCH is most often prenatal; however, prenatal identification is challenging with only single cases or very short case series being reported in the literature.What does this study add?We present the first large case series of 42 patients with prenatally diagnosed PCH.MRI can accurately diagnose PCH with some imaging features predicting classic PCH.On prenatal MRI, cerebellar area measurements correlate with psychomotor development.