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Huntington's Disease-like 2 (HDL2) in North America and Japan
Russell L Margolis1, Susan E Holmes, Adam Rosenblatt
1Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. rmargoli@jhmi.edu
Annals of Neurology
|October 7, 2004
Summary
Huntington's Disease-like 2 (HDL2) is a rare neurodegenerative disorder. It predominantly affects individuals of African ancestry and is caused by a specific gene mutation.
Area of Science:
- Genetics
- Neuroscience
- Medical Genetics
Background:
- Huntington's Disease-like 2 (HDL2) presents similarly to Huntington's disease (HD).
- The genetic cause is a CTG/CAG repeat expansion in the junctophilin-3 gene on chromosome 16q24.3.
Purpose of the Study:
- Determine the frequency of HDL2 in patients with HD-like symptoms.
- Investigate the demographics and genetic characteristics of HDL2 patients.
Main Methods:
- Analyzed nine patient cohorts referred for HD testing or with HD-like phenotypes in North America and Japan.
- Determined HDL2 frequency, repeat length, ancestry, and age of onset in North American cases.
Main Results:
- HDL2 is rare, found in 0-15% of patients without the HD mutation but with HD-like symptoms.
- HDL2 is primarily observed in individuals of African ancestry.
- Repeat expansions ranged from 44-57 triplets, with evidence of maternal transmission instability.
Conclusions:
- The CTG/CAG repeat expansion at 16q24.3 is confirmed as the cause of HDL2.
- Provides preliminary guidance for genetic testing of individuals with HD-like phenotypes.
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