Some studies, however, suggest there are differences in dyneins and other proteins presented in cilia and sperm flagella, possibly explaining the variable presence of infertility and respiratory symptoms in individuals affected by PCD [13, 17] – e.g. CCDC114 gene mutations usually do not lead to infertility due to low gene expression in testicles [12]. The gene discussed is ODAD1; the disease is primary ciliary dyskinesia.