You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Megalencephalic leukoencephalopathy with subcortical cysts and explain in detail?
Megalencephalic leukoencephalopathy with subcortical cysts (MLC, or Van der Knaap disease) is a form of hereditary CNS demyelinating disease.  It belongs to a group of disorders called leukodystrophies. It is characterized by early-onset enlargement of the head (macrocephaly) as well as delayed-onset neurological deterioration to include spasticity, epilepsy, and lack of muscular coordination. MLC does not appear to be a disease that is fatal at birth or early in life despite its symptoms, although the number of patients throughout history known to have the disease is fairly limited.It belongs to a group of disorders called leukodystrophies. A series of cases with megalencephalic leukodystrophy were described by the Indian neurologist Bhim Sen Singhal (1933-) in 1991. However, it is sometimes referred to as Van der Knaap disease after the Dutch neurologist Marjo van der Knaap who described another series of cases with clinical and radiological features in 1995.There are three types of Megalencephalic leukoencephalopathy distinguished by the affected gene: Type 1 caused by autosomal recessive mutations on the MLC1 gene, Type 2A an autosomal recessive mutation on the HEPACAM gene, and Type 2B an autosomal dominant mutation on the HEPACAM gene.

Signs and Symptoms
Head
Macrocephaly
The disease is characterized by megalencephaly, the enlargement of the brain, which is followed by an increase in the size of the actual head.
Central Nervous System
Megalencephaly
The M in MLC stands for “megalencephaly”, the enlargement of the brain
Ataxia
Slow, progressive and early-onset cerebellar ataxia has been noted in many patients
Spasticity
Patients with MLC often have muscle spasms
Seizures
Delay in motor development
 Mild mental retardation
Diffuse swelling of cerebral white matter
 Large subcortical cysts in frontal and temporal lobes
Patients develop cysts on the tips of the temporal and subcortical area
Diffuse spongiform leukoencephalopathy
Vacuolizing myelinopathy
The protective myelin sheath on neurons pulls away from their cells forming small holes in nerve fibers – in turn affecting coordination and walking ability.

Genetics
It is associated with MLC1. The MLC1 gene is located in chromosome 22q13.33 and is in the genomic coordinates 22:50,059,390 – 50,085874. The gene contains 12 exons and that contain a start codon in exon 2 and an untranslated region in the 3’ end. The MLC1 gene product is a 377 amino acid protein highly expressed in the brain. The disease is caused by a homozygous or compound heterozygous mutation in the gene, MLC1. Previous research indicates that deficiency of cell surface protein expression of the MLC1 gene is the basis for the disorder. The mutant protein is expressed in intracellular compartments reducing the membrane surface expression when compared to the wild type.

Diagnosis
Diagnosis of Megalencephalic leukoencephalopathy with subcortical cysts is made with a combination of physical and clinical evaluations