All males do not have 46 xy karyotype: A rare case report

Area of Science:

• Genetics and Developmental Biology
• Human Endocrinology
• Reproductive Medicine

Background:

• Embryonic sex determination is typically defined by the presence (male) or absence (female) of the Y chromosome.
• Genetic anomalies can lead to discrepancies between genetic sex and phenotypic presentation.

Observation:

• A 26-year-old male presented with bilateral gynecomastia, underdeveloped secondary sexual characteristics, and azoospermia.
• Clinical evaluation revealed hypergonadotropic hypogonadism.
• Chromosomal analysis confirmed a 46 XX karyotype, and ultrasound showed an absence of Mullerian structures.

Findings:

• The patient, despite having a 46 XX karyotype (typically female), exhibited male phenotypic characteristics.
• Fluorescent in situ hybridization (FISH) confirmed the presence of the sex-determining region Y (SRY) gene on the X chromosome.
• This indicates a translocation of the SRY gene as the cause of male development in a 46 XX individual.

Implications:

• This case underscores the critical role of the SRY gene in male sex determination, even in the absence of a Y chromosome.
• It highlights the importance of comprehensive genetic and clinical evaluation in cases of atypical sexual development.
• Understanding such variations contributes to the broader knowledge of human sex differentiation and potential clinical management strategies.