An exome-first approach to aid in the diagnosis of primary ciliary dyskinesia

Hum Genet. 2020 Oct;139(10):1273-1283. doi: 10.1007/s00439-020-02170-2. Epub 2020 May 4.

Abstract

Unlike disorders of primary cilium, primary ciliary dyskinesia (PCD) has a much narrower clinical spectrum consistent with the limited tissue distribution of motile cilia. Nonetheless, PCD diagnosis can be challenging due to the overlapping features with other disorders and the requirement for sophisticated tests that are only available in specialized centers. We performed exome sequencing on all patients with a clinical suspicion of PCD but for whom no nasal nitric oxide test or ciliary functional assessment could be ordered. Among 81 patients (56 families), in whom PCD was suspected, 68% had pathogenic or likely pathogenic variants in established PCD-related genes that fully explain the phenotype (20 variants in 11 genes). The major clinical presentations were sinopulmonary infections (SPI) (n = 58), neonatal respiratory distress (NRD) (n = 2), laterality defect (LD) (n = 6), and combined LD/SPI (n = 15). Biallelic likely deleterious variants were also encountered in AKNA and GOLGA3, which we propose as novel candidates in a lung phenotype that overlaps clinically with PCD. We also encountered a PCD phenocopy caused by a pathogenic variant in ITCH, and a pathogenic variant in CEP164 causing Bardet-Biedl syndrome and PCD presentation as a very rare example of the dual presentation of these two disorders of the primary and motile cilia. Exome sequencing is a powerful tool that can help "democratize" the diagnosis of PCD, which is currently limited to highly specialized centers.

MeSH terms

  • Autoantigens / genetics
  • Cilia / metabolism*
  • Cilia / pathology
  • Ciliary Motility Disorders / complications
  • Ciliary Motility Disorders / diagnosis
  • Ciliary Motility Disorders / genetics*
  • Ciliary Motility Disorders / pathology
  • Consanguinity
  • DNA-Binding Proteins / genetics
  • Exome Sequencing
  • Female
  • Gene Expression
  • Genetic Predisposition to Disease*
  • Golgi Matrix Proteins / genetics
  • Humans
  • Male
  • Microtubule Proteins / genetics
  • Mutation
  • Nuclear Proteins / genetics
  • Pedigree
  • Phenotype
  • Pneumonia / complications
  • Pneumonia / diagnosis
  • Pneumonia / genetics*
  • Pneumonia / pathology
  • Repressor Proteins / genetics
  • Respiratory Distress Syndrome, Newborn / complications
  • Respiratory Distress Syndrome, Newborn / diagnosis
  • Respiratory Distress Syndrome, Newborn / genetics*
  • Respiratory Distress Syndrome, Newborn / pathology
  • Respiratory Mucosa / metabolism
  • Respiratory Mucosa / pathology
  • Saudi Arabia
  • Sinusitis / complications
  • Sinusitis / diagnosis
  • Sinusitis / genetics*
  • Sinusitis / pathology
  • Transcription Factors / genetics
  • Ubiquitin-Protein Ligases / genetics

Substances

  • AKNA protein, human
  • Autoantigens
  • CEP164 protein, human
  • DNA-Binding Proteins
  • GOLGA3 protein, human
  • Golgi Matrix Proteins
  • Microtubule Proteins
  • Nuclear Proteins
  • Repressor Proteins
  • Transcription Factors
  • ITCH protein, human
  • Ubiquitin-Protein Ligases