Traits

Traits linked to CT55

cancer/testis antigen 55

The Human Phenotype Ontology links 11 traits to CT55, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the genitourinary system

Trait	How often it is seen
Excess residual spermatozoal cytoplasm	Always
Globozoospermia	Always
Male infertility	Always
Multiflagellar spermatozoa	Always
Reduced sperm motility	Always
Abnormal sperm development	Very often (80–99%)
Absent sperm in semen	Very often (80–99%)
Decreased testicular size	Very often (80–99%)
Non-obstructive azoospermia	Very often (80–99%)
Obstructive azoospermia	Often (30–79%)

Abnormality of the endocrine system

Trait	How often it is seen
Increased circulating gonadotropin level	Very often (80–99%)

How often is among people with one of the gene's conditions, the most often across them, as the Human Phenotype Ontology records it. These pages describe traits and the research behind them; they are not a diagnosis, and a doctor or genetic counsellor is the person to ask about symptoms.

Where this comes from

The Human Phenotype Ontology, release 2026-09-01: the traits linked to CT55 and how often each is seen. Find out more at hpo.jax.org.

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