NfL and pNfH are increased in Friedreich's ataxia.

OBJECTIVE: To assess neurofilaments as neurodegenerative biomarkers in serum of patients with Friedreich's ataxia. METHODS: Single molecule array measurements of neurofilament light (NfL) and heavy chain (pNfH) in 99 patients with genetically confirmed Friedreich's ataxia. Correlation of NfL/pNfH serum levels with disease severity, disease duration, age, age at onset, and GAA repeat length. RESULTS: Median serum levels of NfL were 21.2 pg/ml (range 3.6-49.3) in controls and 26.1 pg/ml (0-78.1) in Friedreich's ataxia (p = 0.002). pNfH levels were 23.5 pg/ml (13.3-43.3) in controls and 92 pg/ml (3.1-303) in Friedreich's ataxia (p = 0.0004). NfL levels were significantly increased in younger patients (age 16-31 years, p < 0.001) and patients aged 32-47 years (p = 0.008), but not in patients of age 48 years and older (p = 0.41). In a longitudinal assessment, there was no difference in NfL levels in 14 patients with repeated sampling 2 years after baseline measurement. Levels of NfL correlated inversely with GAA1 repeat length (r = - 0.24, p = 0.02) but not with disease severity (r = - 0.13, p = 0.22), disease duration (r = - 0.06, p = 0.53), or age at onset (r = 0.05, p = 0.62). CONCLUSION: Serum levels of NfL and pNfH are elevated in Friedreich's ataxia, but differences to healthy controls decrease with increasing age. Long-term longitudinal data are required to explore whether this reflects a selection bias from early death of more severely affected individuals or a slowing down of the neurodegenerative process with age. In a pilot study over 2 years of follow-up-a period relevant for biomarkers indicating treatment effects-we found NfL levels to be stable.

Generation of an induced pluripotent stem cell line from a patient with adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP): HIHCNi003-A.

An induced pluripotent stem cell line, HIHCNi003-A (iPSC-ALSP), was created from a skin biopsy of a patient with adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) caused by a heterozygous c.2512G>C, p.Val838Leu mutation in the CSF1R gene. Skin fibroblasts were reprogrammed using episomal plasmids carrying hOCT4, hSOX2, hKLF4, hL-MYC, and hLIN28. The iPSC-ALSP line exhibits chromosomal stability with conservation of the CSF1R mutation, expresses pluripotency markers and differentiates into endo-, meso-, and ectodermal cells in vitro.

Generation of an induced pluripotent stem cell line from a patient with spinocerebellar ataxia type 3 (SCA3): HIHCNi002-A.

A skin biopsy of a patient with spinocerebellar ataxia type 3 (SCA3, also known as Machado-Joseph disease (MJD)) caused by a CAG trinucleotide repeat expansion in the ATXN3 gene, was used to generate an induced pluripotent stem cell line, HIHCNi002-A (iPSC-SCA3). Skin fibroblasts were reprogrammed using episomal plasmids carrying hOCT4, hSOX2, hKLF4, hL-MYC, and hLIN28. The iPSC-SCA3 line exhibits chromosomal stability with conservation of the ATXN3 repeat expansion, expresses pluripotency markers and differentiates into endo-, meso-, and ectodermal cells in vitro.

STUB1/CHIP mutations cause Gordon Holmes syndrome as part of a widespread multisystemic neurodegeneration: evidence from four novel mutations.

BACKGROUND: CHIP, the protein encoded by STUB1, is a central component of cellular protein homeostasis and interacts with several key proteins involved in the pathogenesis of manifold neurodegenerative diseases. This gives rise to the hypothesis that mutations in STUB1 might cause a far more multisystemic neurodegenerative phenotype than the previously reported cerebellar ataxia syndrome. METHODS: Whole exome sequencing data-sets from n = 87 index subjects of two ataxia cohorts were screened for individuals with STUB1 mutations. In-depth phenotyping by clinical evaluation and neuroimaging was performed in mutation carriers. RESULTS: We identified four novel STUB1 mutations in three affected subjects from two index families (frequency 2/87 = 2.3%). All three subjects presented with a severe multisystemic phenotype including severe dementia, spastic tetraparesis, epilepsy, and autonomic dysfunction in addition to cerebellar ataxia, plus hypogonadism in one index patient. Diffusion tensor imaging revealed degeneration of manifold supra- and infratentorial tracts. CONCLUSIONS: Our findings provide clinical and imaging support for the notion that CHIP is a crucial converging point of manifold neurodegenerative processes, corresponding with its universal biological function in neurodegeneration. Further, our data reveal the second STUB1 family with ataxia plus hypogonadism reported so far, demonstrating that Gordon Holmes syndrome is indeed a recurrent manifestation of STUB1. However, it does not present in isolation, but as part of a broad multisystemic neurodegenerative process. This supports the notion that STUB1 disease should be conceptualized not by historical or clinical syndromic names, but as a variable multisystemic disease defined by disturbed function of the underlying STUB1 gene, which translates into a multidimensional gradual spectrum of variably associated clinical signs and symptoms.