The neuropathology seen is similar to LRRK2-associated PD. None of the genes affected in individuals with 22q11.2DS have previously been linked to PD but there are a number that are likely candidates. These include DGCR8 which is important for biogenesis of brain microDNA, SRPT5 which encodes a protein that interacts with the PARK2 protein, COMT which is involved in regulating dopamine levels, and microRNA miR-185 which is thought to target known PD loci LRRK2. Diagnosis
Diagnosis of DiGeorge syndrome can be difficult due to the number of potential symptoms and the variation in phenotypes between individuals. It is suspected in patients with one or more signs of the deletion. In these cases a diagnosis of 22q11.2DS is confirmed by observation of a deletion of part of the long arm (q) of chromosome 22, region 1, band 1, sub-band 2. Genetic analysis is normally performed using fluorescence in situ hybridization  (FISH), which is able to detect microdeletions that standard karyotyping (e.g. G-banding) miss. Newer methods of analysis include multiplex ligation-dependent probe amplification assay (MLPA) and quantitative polymerase chain reaction (qPCR), both of which can detect atypical deletions in 22q11.2 that are not detected by FISH. qPCR analysis is also quicker than FISH, which can have a turn around of 3 to 14 days.A 2008 study of a new high-definition MLPA probe developed to detect copy number variation at 37 points on chromosome 22q found it to be as reliable as FISH in detecting normal 22q11.2 deletions.
The patient usually has a history of alcohol use disorder or malnutrition and neurological symptoms are sometimes present and can help lead to a diagnosis. MBD can be told apart from other neural diseases due to the symmetry of the lesions in the corpus callosum as well as the fact that these lesions dont affect the upper and lower edges.There are two clinical subtypes of MBD
Type A- Stupor and coma predominate. Radiological imaging shows involvement of the entire corpus callosum. This type is also associated with symptoms of the upper motor neurons.Type B- This type has normal or only mildly impaired mental status and radiologic imaging shows partial lesions in the corpus callosum. Treatment
Treatment is variable depending on individuals. Some treatments work extremely well with some patients and not at all with others. Some treatments include therapy with thiamine and vitamin B complex. Alcohol consumption should be stopped. Some patients survive, but with residual brain damage and dementia. Others remain in comas that eventually lead to death. Nutritional counseling is also recommended. Treatment is often similar to those administered for Wenicke-Korsakoff syndrome or for alcohol use disorder.Type A has 21% mortality rate and an 81% long-term disability rate. Type B has a 0% mortality rate and a 19% long-term disability rate. Recent Research
In a study published in 2015, a patient was observed to have MBD, but no history of excessive alcohol use. It is believed that he had protein, folic acid, and thiamine deficiencies, which are what caused the demyelination of the corpus callosum.