TY - CHAP M1 - Book, Section TI - Molecular Cytogenetics of Contiguous Gene Syndromes: Mechanisms and Consequences of Gene Dosage Imbalance A1 - Shaffer, Lisa G. A1 - Ledbetter, David H. A1 - Lupski, James R. A2 - Valle, David L. A2 - Antonarakis, Stylianos A2 - Ballabio, Andrea A2 - Beaudet, Arthur L. A2 - Mitchell, Grant A. PY - 2019 T2 - The Online Metabolic and Molecular Bases of Inherited Disease AB - Contiguous gene syndromes (CGS) are disorders caused by chromosomal abnormalities, such as deletions and duplications, which result in an alteration of normal gene dosage. Clinically, each CGS is characterized by a specific and complex phenotype, which was recognized in most cases as a genetic syndrome before knowledge of their cytogenetic etiology. The responsible chromosomal segment is usually small on a cytogenetic scale (20 kb), low-copy region-specific repeat sequences. The underlying genome architecture likely facilitates large rearrangements of other regions of the genome.Molecular technologies, primarily PCR and fluorescence in situ hybridization (FISH), have been key to the characterization of CGS and provide powerful and sensitive diagnostic capabilities. For X-linked CGS, multiplex PCR analysis of nullisomic males and FISH analyses of carrier females are efficient strategies for deletion detection. FISH is the method of choice for detection of deletions and translocations in autosomal CGS. Interphase FISH and pulsed-field gel electrophoresis have been used to diagnose chromosomal duplications. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/04/20 UR - ommbid.mhmedical.com/content.aspx?aid=1181419272 ER -