A new method of gene testing (amplicon-based high-throughput sequencing) to identify SPG5 and SPG7 in people with sporadic HSP (no family history) has proved successful, identifying 10 new mutations in the process.
Hereditary spastic paraplegia (HSP) is a neurodegenerative disorder defined clinically by progressive lower limb spasticity and weakness. HSP is a genetically highly heterogeneous condition with at least 46 gene loci identified so far, involving X-linked, autosomal recessive (AR) and autosomal dominant inheritance.
For correct diagnosis, molecular testing is essential because clinical parameters by themselves are not reliable to differentiate HSP forms. The purpose of this study was to establish amplicon-based high-throughput genotyping for AR-HSP.
A sample of 187 index cases with apparently sporadic or recessive spastic paraplegia was analyzed by applying an array-based amplification strategy. Amplicon libraries of the CYP7B1-(SPG5) and SPG7-gene were generated followed by a pooled next-generation sequencing (NGS) approach. We identified three SPG5 and seven SPG7 patients. All had one homozygous or two heterozygous mutations. In total, 20 distinct mutations (CYP7B1,n = 4 and SPG7,n = 16) including two novel CYP7B1 mutations (p.G51R and p.E211KfsX3) and eight novel SPG7 mutations (p.Leu8delinsLeuLeu, p.W29X, p.R139X, p.R247X, p.G344D, p.Leu346_Leu347ins11, p.R398X and p.R398Q) were detected by this comprehensive genetic testing.
Our study illustrates how amplicon-based NGS can be used as an efficient tool to study genotypes and mutations in large patient cohorts and complex phenotypes.
SOURCE: Clin Genet. 2011 Aug;80(2):148-60. doi: 10.1111/j.1399-0004.2011.01715.x. Epub 2011 Jun 13. © 2011 John Wiley & Sons A/S.
Amplicon-based high-throughput pooled sequencing identifies mutations in CYP7B1 and SPG7 in sporadic spastic paraplegia patients.
Department of Medical Genetics, Institute of Human Genetics, Tübingen, Germany.