The new SPG7 gene mutation leads to a novel complicated autosomal recessive hereditary spastic paraparesis phenotype that widens the spectrum of different brain systems that are optionally affected in hereditary spastic paraplegia (HSP). In this novel phenotype, spastic paraparesis is related to cerebral damage of corticospinal tracts. Impairment of attention and executive functions is due to white matter loss in frontal lobes. Furthermore, supranuclear palsy is caused by white matter damage in the midbrain. This multisystem affection, which was detected by the use of diffusion tensor imaging, may reflect a mitochondrial dysfunction that contributes to the underlying pathogenesis of SPG7-HSP.

In this retrospective study, we examined changes in decision-making for and against the predictive genetic test for Huntington's disease including 478 persons at risk who had undergone genetic counselling in one centre in Germany between 1993 and 2004. At the outset of the counselling procedure the majority of subjects (71%) wanted to make use of the test, yet the actual demand of the predictive test result declined from 67 to 38% over the years. In addition, the time interval between counselling session and blood withdrawal was reduced, as determined by the counselees: in 2000-2004 the majority of persons at risk made the appointment for blood withdrawal after the shortest possible time span. Demographic factors of the cohort remained comparatively stable in the investigated time period. An association was evident between the ratio of test usage and the counselling person. These and other possible factors influencing the time flow of predictive DNA testing are discussed. Further studies are necessary to investigate whether changes of test demand rates are a general phenomenon.

The authors report a 73-year-old patient with a natural history of early-onset ALS for 49 years presenting with limb and bulbar amyotrophy and a pyramidal syndrome. Analysis of the locus SPG4 identified a heterozygous duplication mutation (c.304_309dupGCCTCG) within exon 1 of the spastin gene. We propose that sequence alterations of spastin may comprise a genetic risk factor in a greater spectrum of motor neuron disorders including clinical variants of ALS.

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Biallelic PNKP variants cause heterogeneous disorders ranging from neurodevelopmental disorder with microcephaly/seizures to adult-onset Charcot–Marie–Tooth disease. To date, only postnatal descriptions exist. We present the first prenatal diagnosis of PNKP-related primary microcephaly. Pathological examination of a male fetus in the 18th gestational week revealed micrencephaly with extracerebral malformations and thus presumed syndromic microcephaly. A recessive disorder was suspected because of previous pregnancy termination for similar abnormalities. Prenatal trio-exome sequencing identified compound heterozygosity for the PNKP variants c.498G>A, p.[(=),0?] and c.302C>T, p.(Pro101Leu). Segregation confirmed both variants in the sister fetus. Through RNA analyses, we characterized exon 4 skipping affecting the PNKP forkhead-associated (FHA) and phosphatase domains (p.Leu67_Lys166del) as the predominant effect of the paternal c.498G>A variant. We retrospectively investigated two unrelated individuals diagnosed with biallelic PNKP-variants to compare prenatal/postnatal phenotypes. Both carry the splice donor variant c.1029+2T>C intrans with a variant in the FHA domain (c.311T>C, p.(Leu104Pro); c.151G>C, p.(Val51Leu)). RNA-seq showed complex splicing for c.1029+2T>C and c.151G>C. Structural modeling revealed significant clustering of missense variants in the FHA domain with variants generating structural damage. Our clinical description extends the PNKP-continuum to the prenatal stage. Investigating possible PNKP-variant effects using RNA and structural modeling, we highlight the mutational complexity and exemplify a PNKP-variant characterization framework.

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Background: Juvenile ALS (JALS) is a form of chronic motor neuron disease presenting with upper and lower motor neuron symptoms prior to the age of 25 years. Rare cases of JALS with a survival of more than three decades have been described. Genetic risk factors of sporadic JALS are largely unknown. Objective: to describe a male patient with apparently sporadic JALS at the age of 72 years with a natural history of ALS for 48 years. Design: a case report, magnetic resonance imaging of the brain and mutation analysis of the spastin gene (SPG4). Result: at the age of 24 years the patient developed a progressive lower motor neuron syndrome of the left hand followed by paresis and atrophy of the distal left lower limb. In the course of 2 years he showed a pyramidal syndrome of all extremities and a progressive bulbar and pseudobulbar syndrome. Since then he has fulfilled the diagnostic criteria for definite ALS. Recent magnetic resonance imaging of the brain has demonstrated severe occipital, parietal and insular atrophy in decreasing order. Mutation analysis of the locus SPG4 for hereditary spastic paraplegia (HSP) identified a heterozygous protein-changing mutation (c.304_309dupGCCTCG) within exon 1 of the spastin gene. Conclusion: We report the first case of ALS demonstrating a mutation in the HSP-related spastin gene. We propose that sequence variants of spastin might serve as a previously unknown genetic risk factor for JALS. The finding implicates the potential involvement of the spastin gene in a greater spectrum of motor neuron disorders including clinical variants of ALS.