Editing Frameshift mutation (section)

===Tay–Sachs disease===

[[Tay–Sachs disease]] is a fatal disease affecting the central nervous system. It is most frequently found in infants and small children. Disease progression begins in the [[womb]] but symptoms do not appear until approximately 6 months of age. There is no cure for the disease.<ref name="tay sachs">{{cite web|title=Learning About Tay-Sachs Disease|url=http://www.genome.gov/10001220|publisher=National Human Genome Research Institute|access-date=24 March 2013}}</ref> Mutations in the β-hexosaminidase A (Hex A) gene are known to affect the onset of Tay-Sachs, with 78 mutations of different types being described, 67 of which are known to cause disease. Most of the mutations observed (65/78) are single base substitutions or SNPs, 11 deletions, 1 large and 10 small, and 2 insertions. 8 of the observed mutations are frameshift, 6 deletions and 2 insertions. A 4 base pair insertion in exon 11 is observed in 80% of Tay-Sachs disease presence in the [[Ashkenazi]] Jewish population. The frameshift mutations lead to an early stop codon which is known to play a role in the disease in infants. Delayed onset disease appears to be caused by 4 different mutations, one being a 3 base pair deletion.<ref name="Tay-Sachs mutations">{{cite journal|last=Myerowitz|first=R|title=Tay-Sachs disease-causing mutations and neutral polymorphisms in the Hex A gene.|journal=Human Mutation|year=1997|volume=9|issue=3|pages=195–208|pmid=9090523 |doi=10.1002/(SICI)1098-1004(1997)9:3<195::AID-HUMU1>3.0.CO;2-7|doi-access=free}}</ref>