Pontocerebellar Hypoplasia, Type 4, also known as pontocerebellar hypoplasia type 4, is related to pontocerebellar hypoplasia, type 6 and microcephaly, and has symptoms including muscle spasticity, myoclonus and seizures. An important gene associated with Pontocerebellar Hypoplasia, Type 4 is TSEN54 (TRNA Splicing Endonuclease Subunit 54), and among its related pathways/superpathways are RNA Polymerase III Transcription Initiation and tRNA processing. Affiliated tissues include cerebellum and brain, and related phenotypes are seizure and abnormal facial shape