Aneuploidy is the second most important category of chromosome mutations relating to abnormal chromosome number. It generally arises by nondisjunction at either the first or second meiotic division. However, the existence of two chromosomal abnormalities involving both autosomal and sex chromosomes in the same individual is relatively a rare phenomenon. The underlying mechanism involved in the formation of double aneuploidy is not well understood. Parental origin is studied only in a small number of cases and both nondisjunctions occurring in a single parent is an extremely rare event. This chapter reviews the characteristics of double aneuploidies in Down syndrome have been discussed in the light of the published reports.
Part of the book: Health Problems in Down Syndrome
Aptamers are a new class of recognizing agents which are defined as short biomolecules like oligonucleotides and peptides that are used in diagnostics and therapeutics. They can bind to specific targets with extremely high affinity based on their structural conformations. It is believed that in the near future, aptamers could replace monoclonal antibody. The biggest advantage of using aptamers is that the process is in vitro in nature and does not require the use of animals and they also have unique properties, such as thermal stability, low cost, and unlimited applications. Aptamers have been studied as a biomaterial in numerous investigations concerning their use as a diagnostic and therapeutic tool and biosensing probe. DNA aptamers were also used for the diagnosis and treatment of neurodegeneration and neurodegenerative diseases. For example, functional nucleic acid aptamers have been developed to detect Aβ fragments in Alzheimer’s brain hippocampus tissue samples. Aptamers are promising materials for diverse areas, not just as alternatives to antibodies but as the core components of medical equipment. Although they are in the preliminary stages of development, results are quite encouraging, and it seems that aptamer research has a very bright future in neuroscience.
Part of the book: Neuroprotection
Down syndrome (DS) is the most common chromosomal condition associated with mental retardation and is characterized by a variety of additional clinical findings. It occurs in approximately 1 of 800 births worldwide. DS is associated with number of phenotypes including heart defects, leukemia, Alzheimer’s disease, hypertension etc. Individuals with DS are affected by these diseases to variable rates, so understanding the reason for this variation is an important challenge. Multiple genes located both on chromosome 21 and other regions of the genome such as the polymorphism of the amyloid precursor protein (APP) gene contribute to clinical variations. Information on these genetic variations allows early diagnosis and treatment of phenotypes associated with DS. In this chapter, an overview of disease management will be provided by reviewing the genes or miRNAs that cause DS-associated phenotypes.
Part of the book: Down Syndrome and Other Chromosome Abnormalities