Assessment of fibroblast nuclear morphology aids interpretation of LMNA variants

Florence van Tienen, Patrick Lindsey, Miriam Kamps, Ingrid Krapels, Frans Ramaekers, Han Brunner, Arthur van den Wijngaard, Jos Broers

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

The phenotypic heterogeneity of Lamin A/C (LMNA) variants renders it difficult to classify them. As a consequence, many LMNA variants are classified as variant of unknown significance (VUS). A number of studies reported different types of visible nuclear abnormalities in LMNA-variant carriers, such as herniations, honeycomb-like structures and irregular Lamin staining. In this study, we used lamin A/C immunostaining and nuclear DAPI staining to assess the number and type of nuclear abnormalities in primary dermal fibroblast cultures of laminopathy patients and healthy controls. The total number of abnormal nuclei, which includes herniations, honeycomb-structures, and donut-like nuclei, was found to be the most discriminating parameter between laminopathy and control cell cultures. The percentage abnormal nuclei was subsequently scored in fibroblasts of 28 LMNA variant carriers, ranging from (likely) benign to (likely) pathogenic variant. Using this method, 27 out of 28 fibroblast cell cultures could be classified as either normal (n = 14) or laminopathy (n = 13) and no false positive results were obtained. The obtained specificity was 100% (CI 40-100%) and sensitivity 77% (46-95%). We conclude that assessing the percentage of abnormal nuclei is a quick and reliable method, which aids classification or confirms pathogenicity of identified LMNA variants causing formation of aberrant lamin A/C protein.

Original languageEnglish
Pages (from-to)389–399
Number of pages11
JournalEuropean Journal of Human Genetics
Volume27
Issue number3
DOIs
Publication statusPublished - Mar 2019

Keywords

  • LAMIN A/C MUTATIONS
  • DILATED CARDIOMYOPATHY
  • PARTIAL LIPODYSTROPHY
  • MUSCULAR-DYSTROPHY
  • ENVELOPE ALTERATIONS
  • PROGERIA-SYNDROME
  • GENE
  • PHENOTYPE
  • EXPRESSION
  • PRELAMIN

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