Huntington's disease-like syndrome

Huntington's disease-like syndrome
Other names	HDL syndrome
Specialty	Neurology

Huntington's disease-like syndromes (HD-like syndromes, or HDL syndromes) are a family of inherited neurodegenerative diseases that closely resemble Huntington's disease (HD) in that they typically produce a combination of chorea, cognitive decline or dementia and behavioural or psychiatric problems.^[1]

Types

HDL1

HDL1 is an unusual, autosomal dominant familial prion disease. Only described in one family, it is caused by an eight-octapeptide repeat insertion in the PRNP gene. More broadly, inherited prion diseases in general can mimic HD.^[1]

HDL2

HDL2 is the most common HD-like syndrome and is caused by CTG/CAG triplet expansions in the JPH3 gene encoding junctophilin-3. It is almost exclusively restricted to populations of African descent and is actually more common than Huntington's disease in Black South Africans.^[1]

HDL3

HDL3 is a rare, autosomal recessive disorder linked to chromosome 4p15.3. It has only been reported in two families, and the causative gene is unidentified.^[1]

Other

Other neurogenetic disorders can cause an HD-like or HD phenocopy syndrome but are not solely defined as HDL syndromes. The most common is spinocerebellar ataxia type 17 (SCA-17), occasionally called HDL-4. Others include mutations in C9orf72,^[2][3] spinocerebellar ataxias type 1 and 3, neuroacanthocytosis, dentatorubral-pallidoluysian atrophy (DRPLA), brain iron accumulation disorders, Wilson's disease, benign hereditary chorea, Friedreich's ataxia and mitochondrial diseases.^[1]

A Huntington's disease-like presentation may also be caused by acquired causes.^[1]

References

1. Wild, EJ; Tabrizi, SJ (December 2007). "Huntington's disease phenocopy syndromes". Current Opinion in Neurology. 20 (6): 681–7. doi:10.1097/wco.0b013e3282f12074. PMID 17992089. S2CID 37287959.
2. Hensman Moss, DJ; Poulter, M; Beck, J; Hehir, J; Polke, JM; Campbell, T; Adamson, G; Mudanohwo, E; McColgan, P; Haworth, A; Wild, EJ; Sweeney, MG; Houlden, H; Mead, S; Tabrizi, SJ (28 January 2014). "C9orf72 expansions are the most common genetic cause of Huntington disease phenocopies". Neurology. 82 (4): 292–9. doi:10.1212/WNL.0000000000000061. PMC 3929197. PMID 24363131.
3. Cooper-Knock, J; Shaw, PJ; Kirby, J (March 2014). "The widening spectrum of C9ORF72-related disease; genotype/phenotype correlations and potential modifiers of clinical phenotype". Acta Neuropathologica. 127 (3): 333–45. doi:10.1007/s00401-014-1251-9. PMC 3925297. PMID 24493408.

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