An observational study in Azoospermia, Nonobstructive and Cryptozoospermia, sponsored by The Third Affiliated Hospital of Guangzhou Medical University. Recruiting at 1 site in China. Per ClinicalTrials.gov, last updated 2026-07-09.
Sponsored by The Third Affiliated Hospital of Guangzhou Medical University · Observational
Idiopathic non-obstructive azoospermia and cryptozoospermia are severe forms of male infertility in which sperm production is absent or extremely low and the cause is often unknown. This retrospective observational study examined whether mitochondrial DNA variants, particularly the MT-ND1 m.3700G>A variant, are associated with impaired sperm production in Chinese men.
Existing clinical records and available biospecimens from affected men, eligible family members, and fertile controls were analyzed to assess familial inheritance patterns, the frequency of the variant, and its association with infertility phenotypes. No study-related treatment or intervention was provided to human participants.
23 studies on the registry are indexed under Azoospermia, Nonobstructive; 7 are open to participants now.
This study's planned enrollment of 1,200 is above the median of 94 across 10 observational studies indexed under Azoospermia, Nonobstructive.
Browse Azoospermia, Nonobstructive studies →The Third Affiliated Hospital of Guangzhou Medical University is the lead sponsor of 15 studies on the registry; 8 are open to participants now.
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Participants were selected from men receiving care at the Reproductive Medicine Center of the Third Affiliated Hospital of Guangzhou Medical University. The study population included men with idiopathic non-obstructive azoospermia or cryptozoospermia identified through clinical records and available biospecimens; men with normal spermatogenic function or obstructive azoospermia who served as comparison participants; and, when needed, available first-degree relatives and spouses for family-based genetic analyses. Testicular tissue was obtained only from residual specimens following clinically indicated testicular biopsy, TESA, or micro-TESE procedures.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Men with idiopathic non-obstructive azoospermia or cryptozoospermia who were included in the retrospective clinical and genetic analyses.
Fertile men who were included as comparison participants for mitochondrial DNA variant analyses.
Affected participants and available relatives who were included for pedigree, segregation, and maternal inheritance analyses of mitochondrial DNA variants.
Detection and Familial Segregation of the MT-ND1 m.3700G>A Variant
Detection of the MT-ND1 m.3700G\>A mitochondrial DNA variant by sequencing in available biological samples, with assessment of its distribution and maternal segregation among affected male family members, unaffected relatives, unrelated patients with idiopathic non-obstructive azoospermia or cryptozoospermia, and fertile controls.
Time frame: Baseline (single genetic testing assessment at enrollment)
Clinical Classification of Idiopathic Non-obstructive Azoospermia or Cryptozoospermia
Affected participants were classified as having idiopathic non-obstructive azoospermia or cryptozoospermia according to the clinical diagnosis recorded after routine semen analyses and standard clinical evaluation.
Time frame: Baseline (single clinical classification based on pre-enrollment clinical records)
Plan to share: No
No publications or documents are linked to this record.
Started Apr 2021 (actual). Primary completion is estimated for Apr 2027, 72 months after the start.
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The Third Affiliated Hospital of Guangzhou Medical University