Disorder of sex development may result from multiple etiologies, led to many physical impacts involving genital abnormalities. Differentiation of a testis or an ovary from a bipotential gonad is a complex developmental process where various genes and hormones interact. Thus, the causality of sexual ambiguity was supported by the presence of many chromosomal abnormalities, especially when sex determination genes were involved.
A careful clinical examination will primarily interest to define the sexual ambiguity Prader score and the whole genital and extra genital malformation context.
Our study focuses on cases referred to the department of Cytogenetics and Reproductive Biology CHU Farhat Hached for ambiguous genitalia cytogenetic exploration from January 2010 to February 2012.
The 116 patients studied with ambiguous genitalia of varying severity, 80% were younger than 10 years. 7.5% of them showed chromosomal abnormalities.
In 3 patients, the chromosomal abnormality involved the autosomes 4, 5 and 1 with a 4p deletion in Wolf-Hirschhorn syndrome, deletion 5p in Cri-du-chat syndrome and 1q deletion revealed by Comparative Genomic Hybridization-array. Theses anomalies are associated with loss of genital differentiation protein function. In 4 other patients abnormal sexual chromosome number was identified. For 86 children with normal karyotypes 46, XY, SRY gene molecular cytogenetic screening was performed. A deletion may in these cases explain the phenotype.
Identification of gene rearrangements causing urogenital birth defects can have an impact on the diagnosis and genetic counseling. Thus more study is necessary to find new candidate genes in signaling pathways regulating sexual differentiation.