NIH Rare Diseases

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a condition that affects brain development and function. Individuals with this condition have an enlarged brain (megalencephaly) and an abnormality of the white matter in the brain (leukoencephalopathy). White matter consists of nerve fibers covered by a fatty substance called myelin that promotes the rapid transmission of nerve impulses. In MLC, the myelin is swollen and contains numerous fluid-filled pockets (vacuoles). Over time, the swelling decreases and the myelin begins to waste away (atrophy). Leukoencephalopathy can lead to abnormal muscle tensing (spasticity), difficulty coordinating movements (ataxia), cysts in the brain (subcortical cysts), abnormal muscle tone (dystonia), swallowing difficulties, mild to moderate intellectual disabilities, speech difficulties, seizures, and difficulties walking. There are three types of MLC, which are distinguished by their signs and symptoms and genetic cause. Type 1 is caused by mutations in the MLC1 gene. Types 2A and 2B are caused by mutations in the HEPACAM gene. MLC types 1 and 2A are inherited in an autosomal recessive manner, while type 2B is inherited in an autosomal dominant manner. In approximately 5% of individuals with MLC, the cause is unknown. Although there is no specific treatment or cure for MLC, there are ways to manage the symptoms, such as use of antiepileptic drugs, physical therapy, and speech therapy. Management additionally includes avoiding injury to the head, which can temporarily worsen symptoms. A team of doctors or specialists is often needed to figure out the treatment options for each person. Last updated: 9/7/2016

MalaCards based summary

Megalencephalic Leukoencephalopathy with Subcortical Cysts 1, also known as megalencephalic leukoencephalopathy with subcortical cysts, is related to schizophrenia and leukodystrophy, and has symptoms including ataxia, seizures and macrocephaly. An important gene associated with Megalencephalic Leukoencephalopathy with Subcortical Cysts 1 is MLC1 (Megalencephalic Leukoencephalopathy With Subcortical Cysts 1). Affiliated tissues include brain, temporal lobe and cortex, and related phenotype is no phenotypic analysis.

Genetics Home Reference

Megalencephalic leukoencephalopathy with subcortical cysts is a progressive condition that affects brain development and function. Individuals with this condition typically have an enlarged brain (megalencephaly) that is evident at birth or within the first year of life. Megalencephaly leads to an increase in the size of the head (macrocephaly). Affected people also have leukoencephalopathy, an abnormality of the brain's white matter. White matter consists of nerve fibers covered by a fatty substance called myelin. Myelin insulates nerve fibers and promotes the rapid transmission of nerve impulses. In megalencephalic leukoencephalopathy with subcortical cysts, the myelin is swollen and contains numerous fluid-filled pockets (vacuoles). Over time, the swelling decreases and the myelin begins to waste away (atrophy). Individuals affected with this condition may develop cysts in the brain; because these cysts form below an area of the brain called the cerebral cortex, they are called subcortical cysts. These cysts can grow in size and number.

OMIM

Megalencephalic leukoencephalopathy with subcortical cysts is a leukodystrophy characterized by early-onset macrocephaly and delayed-onset neurologic deterioration, including cerebellar ataxia, spasticity, epilepsy, and mild cognitive decline (summary by Lopez-Hernandez et al., 2011). (604004)

UniProtKB/Swiss-Prot

Leukoencephalopathy, megalencephalic, with subcortical cysts, 1: A syndrome of cerebral leukoencephalopathy and megalencephaly characterized by ataxia, spasticity, seizures, delay in motor development and mild mental retardation. The brain appears swollen on magnetic resonance imaging, with diffuse white-matter abnormalities and the invariable presence of subcortical cysts in frontal and temporal lobes.