Fragile X syndrome is an inheritable form of mental impairment. It is a result of the increase of the trinucleotide sequence. During the expansion of trinucleotides, there is a loss of FMR1 protein that results in developmental variations in the cerebral cortex (Sidhu, 67). Dendric cells in the region of the brain that contains extensive trinucleotides are immature in shape. The lost FMR1 gene is only observed in embryonic stages and silenced in adulthood.
X-chromosomes also portray some syndromes such as Rett’s syndrome. Rett’s syndrome is usually caused by impulsive mutations. Most of the people portraying this disorder are female; this is because Rett’s syndrome results in male fetuses’ death. The severity of Rett’s syndrome in women is evidenced by the specific changes in genes loci and inactivation of x-chromosome shapes.
iPS models will also be of great advantage in Down’s syndrome. Down’s syndrome is a result of the trisomy of chromosome 21. Through iPS, human fetal NPCs have been found to develop Down’s syndrome that can be used in the reprogramming process