Local changes in calcium ions (Ca2+) concentrations cause myorelaxation (decrease of muscular hypertonia and spasm) and significant improvement in range of motion.

As patients pass into adolescence, the syndrome is characterized by a coarse and flat face, macroglossia prognathia, inverted lower lip, and psychomotor retardation with muscular hypertonia and contractures.

Pontocerebellar hypoplasia type 4 (PCH type 4) PCH type 4 is associated with severe neonatal encephalopathy, microcephaly, myoclonus, and muscular hypertonia.