has material basis in germline mutation in SPG21 mast syndrome https://www.malacards.org/card/mast_syndrome MONDO:0009568 mast syndrome Mast syndrome Orphanet:101001 SCTID:764734003 MESH:C565409 DOID:0060245 SPG21 GARD:0016939 MEDGEN:343325 Autosomal recessive spastic paraplegia type 21 is a complex type of hereditary spastic paraplegia characterized by an onset in adolescence or adulthood of slowly progressive spastic paraparesis associated with the additional manifestations of apraxia, cognitive and speech decline (leading to dementia and akinetic mutism in some cases), personality disturbances and extrapyramidal (e.g. oromandibular dyskinesia, rigidity) and cerebellar (i.e. dysdiadochokinesia and incoordination) signs. Subtle abnormalities (e.g. developmental delays) may be noted earlier in childhood. A thin corpus callosum and white matter abnormalities are equally reported on magnetic resonance imaging. OMIM:248900 autosomal recessive spastic paraplegia type 21 UMLS:C1855346 hereditary spastic paraplegia