Dysplasia of the fibrous sheath with axonemal and centriolar defects combined with lack of mitochondrial activity as associated factors of ICSI failure in primary ciliary dyskinesia syndrome

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disorder characterized by ciliary dysfunction and impaired mucociliary clearance, resulting in a range of clinical manifestations, including chronic bronchitis leading to bronchiectasis, chronic rhino-sinusitis and otitis media, situs inversus (in about 50% of cases) and severe male infertility (1). PCD was initially characterized in men with Kartagener syndrome in 1982 by ultrastructural analysis that demonstrated dyskinetic or immotile cilia, but not limited to this particular diagnosis (2). The incidence of PCD is estimated at 1/16.000 births based on the prevalence of situs inversus and bronchiectasis (3). In addition, the prevalence of PCD may be much higher in some communities and countries, particularly when inbreeding is present (4). Severe asthenozoospermia and up to complete immobility of the sperm are the main known causes of male infertility in patients with PCD, due to the inability of sperm to reach and fertilize the oocyte correctly. However, if this was the only reason, one would expect that with the use of assisted reproduction techniques (ARTs), particularly when the sperm is injected directly inside the oocyte, therefore without the physiological evolutionary ability to bypass the oocyte plasma membrane and cumulus cells, such as the invasive resourceful intracytoplasmic sperm injection (ICSI), in which one sperm is injected directly into the oocyte, the inability found in the PCD patient to conceive would be more commonly bypassed in the vast majority of cases. Surprisingly, exactly on the contrary, there are only a handful number of reports of successful pregnanies that resulted in childbirth among couples in which the male partner is affected by PCD syndrome and its variants (5). Even when the most advanced ARTs have been used, including alleged intracytoplasmic injection of morphologically selected sperm (IMSI), time lapse monitoring of IVF-produced embryos, preimplantation genetic diagnosis and screening, a high percentage of PCD male partners never get pregnant. The involuntary childlessness critically found in this group of individuals, suggests that in addition to the incapacity of sperm to reach the oocyte, there might be other unknown factors acting. This prompted us to use the arsenal of tests available in a high-complexity anDysplasia of the fibrous sheath with axonemal and centriolar defects combined with lack of mitochondrial activity as associated factors of ICSI failure in primary ciliary dyskinesia syndrome _______________________________________________