A high-throughput resequencing microarray for autosomal dominant spastic paraplegia genes.

Area of Science:

• Genetics
• Neurology
• Molecular Biology

Background:

• Hereditary spastic paraplegias (HSP) are a diverse group of neurological disorders characterized by progressive lower limb spasticity.
• HSP encompasses over 48 subtypes (SPG1-48) with various inheritance patterns, including autosomal dominant, autosomal recessive, and X-linked.
• Current genetic testing establishes etiology in 50-60% of autosomal dominant HSP cases, but phenotype-based genotype prediction is limited.

Purpose of the Study:

• To design and validate a high-throughput resequencing microarray for identifying genetic mutations in autosomal dominant HSP.
• To assess the efficiency of microarray technology in detecting known and novel sequence variations in key HSP-associated genes.
• To improve diagnostic yield for autosomal dominant HSP by enabling large-scale genetic analysis.

Main Methods:

• A custom resequencing microarray was designed for six autosomal dominant HSP genes (ATL1, SPAST, NIPA1, KIF5A, BSCL2, HSPD1) on the Affymetrix CustomSEQ platform.
• The microarray was validated using Sanger-sequenced patients and positive controls with known mutations.
• DNA from 45 additional patients with autosomal dominant spastic paraplegia was analyzed using the microarray and two sequencing analysis software modules (GSEQ, SeqC).

Main Results:

• The microarray successfully identified all missense/nonsense mutations in positive controls, with a 50% detection rate for small insertions/deletions (indels).
• A total of 244 common synonymous single-nucleotide polymorphisms (SNPs) and 22 distinct sequence variations were identified across 53 patients.
• Twelve rare, previously undescribed variants were found, and a genetic diagnosis was achieved in 11% of SPAST-negative cases.

Conclusions:

• Resequencing microarray technology provides an efficient method for high-throughput genotyping and mutation detection in hereditary spastic paraplegia.
• This approach can significantly aid in the genetic diagnosis of autosomal dominant HSP, particularly in identifying novel variants.
• The study demonstrates the utility of microarray technology for studying genotypes and mutations in large patient cohorts for rare neurological disorders.