Genetic map of the spinocerebellar ataxia type 2 (SCA2) region on chromosome 12
- UCLA School of Medicine, Los Angeles, CA (United States); and others
The autosomal dominant ataxias (SCAs) are a clinically and genetically heterogeneous group of neurodegenerative diseases characterized by progressive ataxia. At least four gene loci have been identified: SCA1 on chromosome (CHR) 6, SCA2 on CHR12, Machado-Joseph disease on CHR14, and SCA families that are not linked to any of the above loci. In addition, the gene causing dentato-rubro-pallido-luysian atrophy has been identified as an expanded CAG repeat on CHR 12p. As a necessary step in identifying the gene for SCA2, we now identified closer flanking markers. To do this we ordered microsatellite markers in the now identified closer flanking markers. To do this we ordered microsatellite markers in the region and then determined pairwise and multipoint lod scores between the markers and SCA2 in three large pedigrees with SCA. The following order was established with odds > 1,000:1 using six non-SCA pedigrees: D12S101-7.1cM-D12S58-0cM-IGF1-3.6cM-D12S78-1.4cM-D12S317-3.7cM-D12S84-0cM-D12S105-7.2cM-D12S79-7.0cM-PLA2. Using this ordered set of markers we examined linkage to SCA2 in three pedigrees of Italian, Austrian and French-Canadian descent. Pairwise linkage analysis resulted in significant positive lod scores for all markers. The highest pairwise lod score was obtained with D12S84/D12S105 (Z{sub max}=7.98, theta{sub max}=0.05). To further define the location of SCA2, we performed multipoint linkage analysis using the genetic map established above. The highest location score was obtained between D12S317 and D12S84/D12S105. A location of SCA2 between these loci was favored with odds > 100:1. These data likely narrow the SCA2 candidate region to approximately 3.7 cM. The relatively large large number of markers tightly linked to SCA2 will facilitate the assignment of additional SCA pedigrees to CHR12, and will help in the presymptomatic diagnosis of individuals in families with proven linkage to CHR12.
- OSTI ID:
- 134103
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0839
- Journal Information:
- American Journal of Human Genetics, Vol. 55, Issue Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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