Translating sanger-based routine DNA diagnostics into generic massive parallel ion semiconductor sequencing.

Background: Dideoxy-based chain termination sequencing developed by Sanger is the gold standard sequencing approach and allows clinical diagnostics of disorders with relatively low genetic heterogeneity. Recently, new next generation sequencing (NGS) technologies have found their way into diagnostic laboratories, enabling the sequencing of large targeted gene panels or exomes. The development of benchtop NGS instruments now allows the analysis of single genes or small gene panels, making these platforms increasingly competitive with Sanger sequencing.

Rapidly deteriorating course in Dutch hereditary spastic paraplegia type 11 patients.

Although SPG11 is the most common complicated hereditary spastic paraplegia, our knowledge of the long-term prognosis and life expectancy is limited. We therefore studied the disease course of all patients with a proven SPG11 mutation as tested in our laboratory, the single Dutch laboratory providing SPG11 mutation analysis, between 1 January 2009 and 1 January 2011. We identified nine different SPG11 mutations, four of which are novel, in nine index patients.

Mutations in DDHD2, encoding an intracellular phospholipase A(1), cause a recessive form of complex hereditary spastic paraplegia.

We report on four families affected by a clinical presentation of complex hereditary spastic paraplegia (HSP) due to recessive mutations in DDHD2, encoding one of the three mammalian intracellular phospholipases A(1) (iPLA(1)). The core phenotype of this HSP syndrome consists of very early-onset (<2 years) spastic paraplegia, intellectual disability, and a specific pattern of brain abnormalities on cerebral imaging. An essential role for DDHD2 in the human CNS, and perhaps more specifically in synaptic functioning, is supported by a reduced number of active zones at synaptic terminals in Ddhd-knockdown Drosophila models.