Format

Send to

Choose Destination
J Neurol Sci. 2018 Jul 15;390:200-204. doi: 10.1016/j.jns.2018.04.031. Epub 2018 Apr 21.

A study of Huntington disease-like syndromes in black South African patients reveals a single SCA2 mutation and a unique distribution of normal alleles across five repeat loci.

Author information

1
Division of Human Genetics, National Health Laboratory Service and School of Pathology, University of the Witwatersrand, South Africa. Electronic address: fiona.baine@wits.ac.za.
2
Division of Human Genetics, National Health Laboratory Service and School of Pathology, University of the Witwatersrand, South Africa.

Abstract

Huntington disease (HD) is a progressive neurodegenerative disease, characterised by a triad of movement disorder, emotional and behavioural disturbances and cognitive impairment. The underlying cause is an expanded CAG repeat in the huntingtin gene. For a small proportion of patients presenting with HD-like symptoms, the mutation in this gene is not identified and they are said to have a HD "phenocopy". South Africa has the highest number of recorded cases of an African-specific phenocopy, Huntington disease-like 2 (HDL2), caused by a repeat expansion in the junctophilin-3 gene. However, a significant proportion of black patients with clinical symptoms suggestive of HD still test negative for HD and HDL2. This study thus aimed to investigate five other loci associated with HD phenocopy syndromes - ATN1, ATXN2, ATXN7, TBP and C9orf72. In a sample of patients in whom HD and HDL2 had been excluded, a single expansion was identified in the ATXN2 gene, confirming a diagnosis of Spinocerebellar ataxia 2. The results indicate that common repeat expansion disorders do not contribute significantly to the HD-like phenotype in black South African patients. Importantly, allele sizing reveals unique distributions of normal repeat lengths across the associated loci in the African population studied.

KEYWORDS:

Africa; HD; HD phenocopies; HDL2; Huntington disease; Huntington disease-like 2; Phenocopy; Polyglutamine; Repeat expansions; South Africa

PMID:
29801887
DOI:
10.1016/j.jns.2018.04.031

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center