Whole-exome sequencing reveals a monogenic cause in 56% of individuals with laterality disorders and associated congenital heart defects

J Med Genet. 2022 Jul;59(7):691-696. doi: 10.1136/jmedgenet-2021-107775. Epub 2021 Jul 2.


Background: The molecular basis of heterotaxy and congenital heart malformations associated with disruption of left-right asymmetry is broad and heterogenous, with over 25 genes implicated in its pathogenesis thus far.

Objective: We sought to elucidate the molecular basis of laterality disorders and associated congenital heart defects in a cohort of 30 unrelated probands of Arab-Muslim descent, using next-generation sequencing techniques.

Methods: Detailed clinical phenotyping followed by whole-exome sequencing (WES) was pursued for each of the probands and their parents (when available). Sanger sequencing was used for segregation analysis of disease-causing mutations in the families.

Results: Using WES, we reached a molecular diagnosis for 17 of the 30 probands (56.7%). Genes known to be associated with heterotaxy and/or primary ciliary dyskinesia, in which homozygous pathogenic or likely pathogenic variants were detected, included CFAP53 (CCDC11), CFAP298 (C21orf59), CFAP300, LRRC6, GDF1, DNAAF1, DNAH5, CCDC39, CCDC40, PKD1L1 and TTC25. Additionally, we detected a homozygous disease causing mutation in DAND5, as a novel recessive monogenic cause for heterotaxy in humans. Three additional probands were found to harbour variants of uncertain significance. These included variants in DNAH6, HYDIN, CELSR1 and CFAP46.

Conclusions: Our findings contribute to the current knowledge regarding monogenic causes of heterotaxy and its associated congenital heart defects and underscore the role of next-generation sequencing techniques in the diagnostic workup of such patients, and especially among consanguineous families.

Keywords: Hereditary; and neonatal diseases and abnormalities; congenital; heart defects.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Cohort Studies
  • Exome Sequencing
  • Heart Defects, Congenital* / genetics
  • Heterotaxy Syndrome* / genetics
  • Homozygote
  • Humans
  • Intercellular Signaling Peptides and Proteins / genetics
  • Membrane Proteins / genetics
  • Mutation / genetics


  • DAND5 protein, human
  • Intercellular Signaling Peptides and Proteins
  • Membrane Proteins
  • PKD1L1 protein, human