Microcephaly with Simplified Gyral Pattern (MSG) is a congenital malformation of the brain due to neuronal and glial proliferatioin. The condition is defined by severe microcephaly, accompanied with reduced number of and shallow appearance of gyri. In addition, the cortex is of normal or reduced thickness, and has a normal architecture. Five different types of MSG have been observed, differing in their severity. Type 1 is associated with a normal neonatal course, mild spasticity, and absence of seizures. The most severe form is Type 5, which is characterized by arthrogyposis, severe spasticity, and neonatal seizures. All forms are associated with moderate to severe mental retardation. The more severe types present with feeding difficulties, abolished reflexes, and hypotonia. Some researchers believe that MSG and Microcephaly Vera represent a continuous phenotype.
Brain scan using MRI is the best method to diagnose MSG. Differential diagnosis includes Lissencephaly. However, the cortex is thickened in Lissencephaly and its architecture is abnormal, both of which features can be used to differentiate between the two conditions. It is possible to diagnose the condition in the prenatal condition by fetal imaging. However, confirmation of this diagnosis can only be done at least 30 weeks of gestation. No treatment is available for MSG. Prognosis is usually poor for Types 2 to 5. Physiotherapy, speech therapy, and occupational therapy needs to be provided to the patients. Anticonvulsants may be used to control the seizures.