STUB1 Mutations in Autosomal Recessive Ataxias – Evidence for Mutation-Specific Clinical Heterogeneity

    September 2014 in “ Orphanet Journal of Rare Diseases ”
    Ketil Heimdal, Mònica Sánchez-Guixé, Ingvild Aukrust, Jens Bollerslev, Ove Bruland, Greg Eigner Jablonski, Anne Kjersti Erichsen, Einar Gude, Jeanette Koht, Sigrid Erdal, Torunn Fiskerstrand, Bjørn Ivar Haukanes, Helge Boman, Lise Bjørkhaug, Chantal Tallaksen, Per M. Knappskog, Stefan Johansson
    TLDR Different STUB1 gene mutations cause varied symptoms in autosomal recessive ataxias.
    The study identified three mutations in the STUB1 gene in two families with autosomal recessive cerebellar ataxia (ARCA) and cognitive impairment, revealing significant clinical heterogeneity. Using homozygosity mapping and exome sequencing, researchers found a homozygous missense variant (c.194A > G, p.Asn65Ser) in three siblings and a compound heterozygous mutation (c.82G > A, p.Glu28Lys and c.430A > T, p.Lys144Ter) in another patient. Functional studies showed that these mutations impaired CHIP’s ubiquitin ligase activity and reduced CHIP levels in patient fibroblasts. Clinical symptoms varied widely, including diabetes, alopecia, uveitis, and ulcerative colitis, underscoring the complexity of genotype-phenotype correlations in STUB1-related ataxias.
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