In MSA-C, a "hot cross bun" sign is sometimes found; it reflects atrophy of the pontocerebellar tracts that give T2 hyper intense signal intensity in the atrophic pons.MRI changes are not required to diagnose the disease as these features are often absent, especially early in the course of the disease. Additionally, the changes can be quite subtle and  are usually missed by examiners who are not experienced with MSA. Pathologic
Pathological diagnosis can only be made at autopsy by finding abundant GCIs on histological specimens of the central nervous system.Contrary to most other synucleinopathies, which develop α-synuclein inclusions primarily in neuronal cell populations, MSA presents with extensive pathological α-synuclein inclusions in the cytosol of oligodendrocytes (glial cytoplasmic inclusions), with limited pathology in neurons. MSA also differs from other synucleinopathies in its regional pathological presentation, with α-synuclein positive inclusions detected predominantly in the striatum, midbrain, pons, medulla and cerebellum, rather than the brainstem, limbic and cortical regions typically effected in Lewy inclusion diseases. However, recent studies using novel, monoclonal antibodies specific for C-terminally truncated α-synuclein (αSynΔC) have now shown that neuronal α-synuclein pathology is more abundant than previously thought. One group revealed robust α-synuclein pathology in the pontine nuclei and medullary inferior olivary nucleus upon histological analysis of neurological tissue from MSA patients.
Benign hereditary chorea (BHC), also known as benign familial chorea, is a rare autosomal dominant neurogenetic syndrome. It typically presents itself in childhood with isolated chorea, with average to below average intelligence. Unlike other neurogenetic causes of chorea such as Huntingtons disease, BHC is not progressive, and not associated with cognitive decline or psychiatric problems in the vast majority of cases.The first description of BHC was reported in 1967 in an African American family from Mississippi. Two brothers reportedly had delayed motor development in childhood and were diagnosed with chorea. These findings were reaffirmed by other families reporting similar traits and an autosomal dominant pattern of inheritance was suggested. However, heterogeneity in the presentations of the affected individuals made confirmation of these diagnoses of BHC difficult to prove. Features reported in these families, including dystonia, tremor, and myoclonus, led researchers to question whether BHC actually represents different diagnoses with similar phenotypes inappropriately grouped together.Further research in 2000 confirmed a connection between a Dutch family reporting similar characteristics of BHC and one of the original families. The investigators identified a linkage to a disease locus on the long arm of chromosome 14 from this connection. Signs and Symptoms
Benign Hereditary Chorea is characterized by early onset of an abnormal gait, speech articulation difficulties, anxiety, and chorea.The clinical spectrum of symptoms resulting from BHC is vast, manifesting as thyroid agenesis to dysarthria to distress syndrome.