Genetic Advances | Angelman Syndrome | Down Syndrome | Fetal Alcohol Spectrum Disorders | Fragile X Syndrome | Prader-Willi Syndrome | Rett Syndrome | Velocardiofacial Syndrome (Chromosome 22q11 Deletion Syndrome) | Williams Syndrome
In the last decade, advances in the field of genetics have
contributed greatly to our understanding of intellectual disability.
The human genome mapping project and gene knockout animal studies
have enabled scientists to map specific intracellular changes associated
with gene mutations associated with cognitive deficits. Improved
diagnostic methods, including high-resolution karyotyping, subtelomeric
screening, chromosome microdissection, nuclear magnetic resonance
spectroscopy (MRS), and fluorescence in situ hybridization (FISH)
have made it possible to determine etiology in many more cases of
intellectual disability, including milder forms of the disorder
(Vasconcelos 2004). Further, specific genes have been identified,
such as MECP2, responsible for
over 80% of cases of Rett syndrome (Amir et al. 1999).
Below, we review some common genetic syndromes associated with intellectual