MSSP is a rare congenital disorder that has so far been reported in only a handful of families worldwide. It is characterized by microcephaly, primordial dwarfism, polymicrogyria and intrauterine growth retardation. Patients also tend to suffer from severe intellectual disability, delayed motor development, delayed speech development and microcephaly related craniofacial dysmorphism. Brain MRIs of affected patients may reveal several abnormal findings such as simplified gyration, areas of lissencephaly or pachygyria, dysgenesis or agenesis of the corpus callosum, periventricular heterotopia of grey matter and a deformed ventricular system.
MSSP patients require life-long treatment and support. Treatment is focused on symptoms and may include physical therapy, speech therapy and educational aids. Anti-epileptic medications are administered in the case of seizures.