RESUMO
"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."