Down Syndrome (DS) is a genetic condition that results due to presence of an extra copy of chromosome 21. The condition occurs in approximately 1 of 830 live births. It is associated with delayed physical and mental development, mild to moderate learning disabilities, facial changes and low muscle tone of the affected individual.
Down syndrome is not commonly inherited and parents of an affected individual may be genetically normal. Occurrence may be described as sporadic-chance events. There are 3 types of DS namely: Trisomy 21 (nondisjunction), Translocation and Mosaicism. Trisomy 21, which accounts for approx 95% of DS is caused by a failure of the 21st chromosome to separate during egg or sperm development. Mosaicism is the least common variant of DS and shows a mixture of two types of cells, some containing the usual 46 chromosomes and some containing 47. Those cells with 47 chromosomes contain an extra chromosome 21. In translocation variant, an additional copy of chromosome 21 may attach to another chromosome, usually chromosome 14.
Diagnosis of Down syndrome is possible during pregnancy, however the condition cannot be prevented. Conventional treatment involves early childhood intervention comprising of behavioral and speech therapy along with pharmacological management (when indicated). Antioxidants, inhibition of gamma secretase enzyme, adrenergic agonists and memantine may be used. Individuals with DS are at greater risk of developing several systemic illnesses. Treatment goals are to improve life expectancy of affected individuals, though conventional therapies do little in improving quality of life.
Regenerative medicine and stem cell therapy has been shown to reduce the intensity of symptoms of Down syndrome when carried out at an early stage. Additionally, immunological deficiencies are also corrected. Studies have shown reduced levels of vascular endothelial growth factor (VEGF) and nitric oxide in fetuses with DS, thereby suggesting a role for these molecules in the pathogenesis. Platelet rich plasma (PRP) which is a rich source of various growth factors ,including VEGF may aid in modulating systemic responses arising due to VEGF deficiency.
It has also been postulated that neurons in patients with DS are shorter, irregular and have misshapen axons along with fewer dendrites. Mesenchymal stem cells have been shown to have neural differentiation potential, therefore may aid in regeneration of normal neurons.
The multi-differentiation, immunomodulatory potential of stem cells may aid to improve the overall quality of life in patients with Down syndrome. The advantage of this form of therapy is that, cell based therapy addresses the pathology of Down syndrome, thereby providing more stable results that are maintained over longer periods of time.