Methods
Ethical considerations and
study participants consent
77 infertile male patients with unexplained (idiopathic) non-obstructive
azoospermia or severe to extreme oligozoospermia and their unaffected
parents were enrolled from the Radboudumc outpatient clinic and
Newcastle upon Tyne Hospitals NHS Foundation Trust (Newcastle, UK). This
study was approved by the ethics Committees/Institutional Review Boards
((Nijmegen: NL50495.091.14 version 5.0, Newcastle: REC Ref: 18/NE/0089).
Written informed consent from all patients and their parents was
obtained.