XX Male: Early Detection With Prenatal Testing

Abstract

A 46,XX male represents a variant of Klinefelter syndrome (47,XXY), under the category of a disorder of sex development (DSD). Despite possessing an XX karyotype, these individuals exhibit a male phenotype, which, in this case, results from a translocation of the SRY gene from the Y chromosome onto the X chromosome. This genetic alteration results in the development of male gonadal characteristics. This case report outlines a prenatal diagnosis of a 46,XX female in conflict with a level 2 ultrasound. It details the patient's presentation, diagnosis of an SRY-positive 46,XX male, and medical history. The discussion focuses on the advantages of early identification and intervention in managing symptom progression and addressing fertility challenges through hormone replacement therapy. Further exploration of 46,XX DSD early detection and the underlying mechanisms is essential for refining diagnostic and therapeutic approaches that result in a greater quality of life for these patients.

Keywords: de la chapelle syndrome; disorder of sex development (dsd); fluorescence in situ hybridization (fish); genetic karyotype; klinefelter syndrome; level 2 ultrasound; noninvasive prenatal test; sry gene.

Figure 1. The mother's 20-week level 2 ultrasound scan showing the presence of male genitalia. In both photos, the red arrow indicates the scrotum and the blue arrow indicates the penis.

Figure 2. Karyotype analysis revealing two X chromosomes and the absence of a Y chromosome.

Figure 3. A FISH of metaphase chromosomes, shown in blue. The FISH displayed two X chromosomes (green regions) and the presence of the SRY gene (pink region).

FISH: fluorescence in situ hybridization