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mast syndrome (SPG21) - Clinical Profile, Genes & Research | Kisho | Kisho

Rare Disease

mast syndrome

MONDO:0009568

Also known as:SPG21autosomal recessive spastic paraplegia 21autosomal recessive spastic paraplegia type 21

Overview

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.

GeneticsAutosomal recessive · SPG21 (chr 15)

OnsetADULT

Clinical Presentation

Built from Human Phenotype Ontology (HPO) phenotype annotations and GeneReviews clinical descriptions. Features represent findings documented across known cases — not an exhaustive list of possible symptoms.

Features include always present findings: Hypertonia, Shrinkage of the cerebellum (cerebellar atrophy), Periventricular white matter hyperintensities, and Thin corpus callosum and others; and very common findings: Motor delay and Abnormal pyramidal sign. 34 total HPO annotations.

Organ System	Phenotype Count	Example Features
Brain and nerves	19	Periventricular white matter hyperintensities, Akinetic mutism, Spastic paraparesis

Genetic Landscape

SPG21 function has not been fully characterized.

Mast syndrome is associated with mutations in the SPG21 gene on chromosome 15.

Diagnosis

Genetic testing for SPG21 is available. Testing is considered confirmatory for diagnosis.

Biomarker and diagnostic research for mast syndrome has been reported in the published literature.

Prognosis

Phenotype severity distribution: 10 always present features, 2 very common features, 11 common features.

Estimated prevalence: <1 in 1,000,000 (VERY_RARE).

Research Landscape

Sourced from ClinicalTrials.gov and PubMed. Publication types are classified using NLM-curated article metadata; research type breakdowns reflect the nature of published work for this disease.

No clinical trials have been registered for mast syndrome.

26 publications have been identified in PubMed for mast syndrome. Research spans Epidemiology / Natural History (27%), Diagnostic / Biomarker (23%), and Basic Science / Preclinical (19%).

Research Type	Count	% of Total
Disease patterns and progression	7	27%

Data assembled from 6 of 12 sources · Last updated Sep 19, 2026, 5:31 AM UTC

MONDOHPOClinicalTrials.govFDAPubMedHGNCClinVarClinGenGeneReviewsOrphanetOMIMRUSP

Medical References

External Resources

OMIM

Online Mendelian Inheritance in Man

OMIM:248900

Orphanet

European rare disease database

Orphanet:101001

GARD

Genetic and Rare Diseases Info Center

GARD:16939

Questions for Your Care Team

→Should my partner and I meet with a genetic counselor to discuss carrier status and family planning?
→Are there specialists or centers of excellence for this condition in my area?
→Is there a patient registry I should consider joining?

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mast syndrome

Overview

Clinical Presentation

Genetic Landscape

Diagnosis

Prognosis

Research Landscape

Medical References

External Resources

OMIM

Orphanet

GARD

Questions for Your Care Team

Questions for Your Care Team

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mast syndrome

Overview

Clinical Presentation

Genetic Landscape

Diagnosis

Prognosis

Research Landscape

Medical References

External Resources

OMIM

Orphanet

GARD

Related Diseases

Questions for Your Care Team

Questions for Your Care Team

Explore clinical features

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