6533b7d0fe1ef96bd1259f7f

RESEARCH PRODUCT

Laboratory investigations in genetic syndromes: examples of clinical approach in the neonatal unit.

subject

description

Contiguous gene deletion syndromes: the importance of an accurate genetic definition for a careful clinical monitoring. Contiguous gene deletion syndromes are so named because the deletion manifests as a distinctive cluster of otherwise unrelated single-gene disorders in the same subject. An accurate genetic definition of the deleted region is extremely important for the appropriate management of these patients and for unravelling the function of the involved genes. The microarray-based comparative genomic hybridization (CGH arrays) analysis is the actual molecular method able to accurately define the bounds of a deleted region, since it allows an evaluation of DNA copy number alterations associated to chromosome abnormalities, with higher resolution than classical cytogenetics or chromosomal banding. The clinical presentation, the diagnostic course, the genetic investigations and the follow-up of a patient harbouring a contiguous gene deletion syndrome will be presented during the seminar. The newborn with ambiguous genitalia: diagnostic approach toward clinical and genetic definition. Disorders of sexual differentiation may depend on several different causes and pathogenetic mechanisms, which may interfere at different stages of the complex pathway of sexual determination and differentiation. Several genes are involved, together with hormones and receptors. The main disorders of sexual differentiation are characterized by dissociation between chromosomes and gonads or gonads and external genitalia appearance. Clinical phenotypes may be distinguished in true hermaphroditism and male or female pseudohermaphroditism. Diagnostic definition is based on clinical and instrumental evaluation and laboratory investigations (hormonal, cytogenetic and molecular genetic investigations). Early diagnosis may allow an appropriate medical and/or surgical treatment, involving a multidisciplinary equipe. The correct gender assessment must be guided by clinical and genetic diagnosis and, in the meantime, by the possibility of anatomic and functional recovery and the future reproductive opportunities.