Huntington's Disease-Like 2 (HDL2), caused by a CTG/CAG expansion in JPH3 on chromosome 16q24, is the most common Huntington's Disease (HD) phenocopy in populations with African ancestry.
The present study aimed to characterize the genetic basis of the Huntington disease phenotype in South Africans and to investigate the possible origin of the JPH3 mutation.
Recognition of and testing for HDL2 is important in South Africa's large Black population, and HD testing services cannot be considered complete unless testing for both HD1 and HDL2 are undertaken.
The study on 244 patients referred with the clinical diagnosis of HD and without mutation of the IT15 gene revealed one case of SCA17 but did not disclose the presence of two other diseases with a similar clinical manifestation: DRPLA and HDL2.
The authors report a large series of patients with Huntington disease (HD)-like phenotype without CAG repeat expansions in the IT15 gene that were screened for the newly identified CAG/CTG expansion in the gene encoding junctophilin-3.
The authors report a large series of patients with Huntington disease (HD)-like phenotype without CAG repeat expansions in the IT15 gene that were screened for the newly identified CAG/CTG expansion in the gene encoding junctophilin-3.