Endocrine Abstracts

Background: There is significant variation in the phenotypic profiles of cases with chromosomal differences in sex development (DSD), including those with a mosaic form of monosomy X in their cell lines. The study aims to describe variations in clinical, hormonal, and cytogenetic findings in cases with chromosomal DSD, particularly those involving monosomy X.

Methods: The study recruited DSD cases from 4 hospitals in our region; cases with mosaic monosomy X were analyzed for clinical data on age, ethnicity, hormonal and cytogenetic results, and the presence of the SRY gene.

Results: Excluding 46,XX DSD cases, the study included 59 DSD cases. Six of these exhibited mosaicism involving a monosomy X cell line. Among them, two were raised as boys (aged 2 and 5.5 years), who carried XX/XO cell lines detected by FISH, and only one had the SRY gene. Their external genitalia scores were 2.5 and 9, respectively. CytoSNP array analysis showed aberrations on chromosomes 3 and X. The remaining four cases (aged 1.7–16.7 years) had a Y chromosome in their cell lines, either XYY, XY, or XXY, and all carried the SRY gene. Two cases of girls presented with clitoromegaly and absence of Müllerian structures with high levels of gonadotrophins. The other two boys were examined due to undervirilized external genitalia.

Conclusion: The study emphasizes the wide variation in clinical findings in cases with mosaic monosomy X, underscoring the complexity of these cases. The findings also highlight the importance of comprehensive clinical, hormonal, and genetic assessment in individuals with DSD to characterize their condition and guide appropriate management accurately.