Huntington's Disease Genetic Heterogeneity In African Patients
SUMMARY Huntington’s disease has been reported to occur rarely in black patients. A new genetic variant “Huntington’s disease like 2” (HDL2), occurring more frequently in Blacks, has recently been described. The absence of an expanded tri-nucleotide repeat at the chromosome 4 HD locus was previously regarded as a way of excluding classical Huntington’s disease (HD). The objective of this paper is to describe a number of black patients with genetically proven Huntington’s disease and review its occurrence in Africa. Methods: Eleven black families (twelve subjects), with genetically proven Huntington’s disease are described, nine from the Dr George Mukhari Hospital and two from private practice in Tshwane. Results: Chorea was present in all 12 patients and cognitive decline in nine. Nine had an age of onset between 30-50 years. Six families exhibited expansion of the trinucleotide repeat at the chromosome 4, IT 15 gene (HD) and five a Junctophilin (JPH3) trinucleotide expansion at chromosome 16 (HDL2). The HDL2 subtype showed a tendency towards a later age of onset. Conclusions: The clinical presentation of the two genotypes (i.e., HD or HDL2) appears to be similar. The actual rate of occurrence of Huntington’s disease in Blacks may require reassessment. With the number of Huntington’s chorea patients occurring in our area (Garankuwa), the possibility of clustering of the condition arises.
Daliwonga Sithembele Magazi, Medunsa
C H van der Meyden,
Huntington's disease; Genetics; HDL2; HD
Cite this article
South African Medical Journal 2008;98(3):200.
Date submitted: 2007-07-23
Date published: 2008-01-10
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