A 7.5-Mb duplication at chromosome 11q21-11q22.3 is associated with a novel spastic ataxia syndrome.

BACKGROUND

The autosomal dominant spinocerebellar ataxias are most commonly caused by nucleotide repeat expansions followed by base-pair changes in functionally important genes. Structural variation has recently been shown to underlie spinocerebellar ataxia types 15 and 20.

METHODS

We applied single-nucleotide polymorphism (SNP) genotyping to determine whether structural variation causes spinocerebellar ataxia in a family from France.

RESULTS

We identified an approximately 7.5-megabasepair duplication on chromosome 11q21-11q22.3 that segregates with disease. This duplication contains an estimated 44 genes. Duplications at this locus were not found in control individuals.

CONCLUSIONS

We have identified a new spastic ataxia syndrome caused by a genomic duplication, which we have denoted as spinocerebellar ataxia type 39. Finding additional families with this phenotype will be important to identify the genetic lesion underlying disease.