Progrès en génie génétique
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Cytogenetic Profiles of a Large Cohort of Patients with Sexual Developmental Disorders; a 22-Year Single-Center Experience

Osman Demirhan

Although Disorder of Sexual Developmental (DSD) is rare, complementary clinical, genetic and hormonal diagnoses are needed for the diagnosis of a baby born with ambiguous genitalia or uncertain whether it is a boy or a girl. This is the largest retrospective cytogenetic study of DSD patients in Turkey. The aim of this study is to determine the frequency and structure of Chromosomal Abnormalities (CAs) seen in patients with the clinical spectrum of Ambiguous Genitalia (AG), Hypogonadism (HG), Intersex (IS), Hypospadias (HS), Testicular Feminization (TF) and Vaginal Hypoplasia (VH) between 1990 and 2012. Chromosome analysis was performed on 117 patients who applied to our laboratory with the complaint of DSD. For this, heparinized peripheral blood samples were cultured and analyzed according to standard cytogenetic methods. Percentage rates of all patients having AG, HG, HS, IS, TF and VH irregularities were 53.8%, 27.4%, 8.5%, 5.1%, 3.4% and 1.7%, respectively. Of the patients, 64.9% had normal karyotype and 35.1% had abnormal chromosome setup. In 17 (15.3% of all) patients, the phenotypic sex did not match with the genotypic sex (46, XX; 46, XY). Sex-chromosome mismatch chimerism was found in 7 patients (6.0%) (46, XX/46, XY chimeric individuals). Sixteen (13.7% of all) patients had mosaicism of the sex chromosomes. Structural abnormalities were found in gonosomal and autosomal chromosomes in 8 patients (6.3%). Our current findings have shown that CAs play a role in approximately 39% of patients with DSD, and those patients with mosaic karyotype may actually have chimerism and it is difficult to predict the clinical outcome in these patients. Additional molecular and hormonal techniques should be applied in patients with genotype-phenotype mismatch.