A missense variant in NUF2, a component of the kinetochore NDC80 complex, causes impaired chromosome segregation and aneuploidy associated with microcephaly and short stature

Hum Genet. 2021 Jul;140(7):1047-1060. doi: 10.1007/s00439-021-02273-4. Epub 2021 Mar 15.

Abstract

Mutations in proteins involved in cell division and chromosome segregation, such as microtubule-regulating, centrosomal and kinetochore proteins, are associated with microcephaly and/or short stature. In particular, the kinetochore plays an essential role in mitosis and cell division by mediating connections between chromosomal DNA and spindle microtubules. To date, only a few genes encoding proteins of the kinetochore complex have been identified as causes of syndromes that include microcephaly. We report a male patient with a rare de novo missense variant in NUF2, after trio whole-exome sequencing analysis. The patient presented with microcephaly and short stature, with additional features, such as bilateral vocal cord paralysis, micrognathia and atrial septal defect. NUF2 encodes a subunit of the NDC80 complex in the outer kinetochore, important for correct microtubule binding and spindle assembly checkpoint. The mutated residue is buried at the calponin homology (CH) domain at the N-terminus of NUF2, which interacts with the N-terminus of NDC80. The variant caused the loss of hydrophobic interactions in the core of the CH domain of NUF2, thereby impairing the stability of NDC80-NUF2. Analysis using a patient-derived lymphoblastoid cell line revealed markedly reduced protein levels of both NUF2 and NDC80, aneuploidy, increased micronuclei formation and spindle abnormality. Our findings suggest that NUF2 may be the first member of the NDC80 complex to be associated with a human disorder.

Publication types

  • Case Reports

MeSH terms

  • Abnormalities, Multiple / genetics*
  • Abnormalities, Multiple / pathology
  • Adolescent
  • Aneuploidy*
  • Body Height / genetics
  • Cell Cycle Proteins / genetics*
  • Cell Line
  • Chromosome Disorders / genetics*
  • Chromosome Disorders / pathology
  • Chromosome Segregation*
  • Cytoskeletal Proteins / genetics
  • Down-Regulation
  • Growth Disorders / genetics
  • Humans
  • Male
  • Microcephaly / genetics
  • Mutation, Missense*
  • Proteasome Endopeptidase Complex / metabolism
  • Spindle Apparatus / pathology
  • Ubiquitin / metabolism
  • Whole Genome Sequencing

Substances

  • Cell Cycle Proteins
  • Cytoskeletal Proteins
  • NDC80 protein, human
  • NUF2 protein, human
  • Ubiquitin
  • Proteasome Endopeptidase Complex