RESUMO
Background: A newborn with ambiguous genitalia needs prompt evaluation to detect life-threatening conditions [e.g., salt-losing crisis in congenital adrenal hyperplasia [CAH]] and gender assignment. Sex assignment in these children continues to be a challenging diagnostic and therapeutic problem. We studied the causes and characteristics of ambiguous genitalia in children who were referred to a cytogenetic laboratory
Patients and Methods: We retrospectively reviewed a total of 120 medical records of patients with a primary indication of ambiguous genitalia that were referred to the cytogenetic lab for karyotyping during the period of 1989 to 1999. Diagnosis was based on a clinical impression from the primary physician, who was primarily a staff pediatrician, endocrinologist and/or pediatric urologist
Results: CAH was the underlying cause of ambiguous genitalia in 41 of 63 patients with ambiguity due to endocrine causes; 39 of these patients showed a 46,XX karyotype and 2 cases were 46,XY [both the 46,XY patients had 3 beta-hydroxylase deficiency]. In 57 patients, ambiguous genitalia were due to congenital developmental defects. The most common endocrine case of ambiguous genitalia was 21-OH deficiency. Seven patients were classified as idiopathic with six showing the 46,XY and one the 46,XX karyotype. Gender was reassigned at birth or at diagnosis in 15 patients
Conclusion: The etiology of ambiguous genitalia is variable. The physician managing these families could minimize the trauma of having a child with unidentified sex by providing appropriate genetic counseling so that the parents can make an early decision. Prenatal DNA testing in at-risk families should be considered and appropriate therapy offered to minimize or prevent genital ambiguity
RESUMO
Fragile X syndrome is the most common cause of inherited mental retardation. Patients with fragile X syndrome show variable mental disability, typical long and narrow facial appearance with large ears and prominent fontanelle and frequent macro-orchidism. It is generally associated with a fragile site at Xq 27.3, which can be observed in the metaphase chromosome following selective culture conditions. At the molecular level, the fragile X syndrome is associated with an amplification of CGG repeat sequence of the FMR1 gene. The prevalence estimates are reported as one per 1500 males and one per 2500 females. Estimated prevalence rates of fragile X syndrome in different ethnic groups range from 0.4-0.8 per 1000 in males and 0.2-0.6 per 1000 in females. In this study, we have determined the frequency of fragile X-positive cases in 305 preselected patients. Materials and Three hundred and five Saudi patients with mental retardation/developmental delay/clinical suspicion of fragile X syndrome were screened for fragile X chromosome by cytogenetic methods. The majority of patients [95.59%] screened were under the age of 20 years. Two hundred and ninety-nine patients [98.03%] were in the category of mild to moderate mental retardation. Twenty-four males [7.86%] and two females [0.65%] were found to express fragile X site at q27.3. The frequency of fragile X-positive cells in males ranged between 7% and 58% [mean 26 13.11], while in the females it was between 14% and 21% [mean 12.5 35], respectively. The frequency of fragile X positive cases found in this study is similar to other reports of fragile X syndrome in preselected patients