Down syndrome is caused by an individual having an extra chromosome. In the United States, 1 in every 691 babies are born with Down syndrome, making it the most common genetic condition. The genetic condition affects each child’s course of development differently. Some of the most common physical traits are small stature, slanted eyes, and low muscle tone. http://www.ndss.org/Down-Syndrome/What-Is-Down-Syndrome/
If your child has been diagnosed with non-mosaic Down syndrome and meets SSA’s financial requirements, he or she will automatically start receiving SSI payments. You can prove your child’s non-mosaic Down syndrome disability by a laboratory test or by obtaining a report from your child’s physician. The specific laboratory test needed is called a karyotype chromosomal analysis. If the laboratory results are unavailable, you will need to obtain a physician report stating that your child has the chromosome disorder consistent with the karyotype analysis or that the child has Down syndrome with the distinctive facial or other physical features. For a more detailed overview of the needed medical evidence please visit SSA’s website at http://www.ssa.gov/disability/professionals/bluebook/110.00-MultipleBody-Childhood.htm#110_06.
Your child may be eligible to receive SSI benefits right away. Generally, the Social Security Administration takes anywhere between three to five months to make a decision on whether your child is disabled and eligible to receive SSI benefits. However, SSA will start making payments right away if you can show that your child is suffering from non-mosaic Down syndrome.
Other conditions that make your child eligible for immediate SSI payments include HIV infection, total blindness, total deafness, cerebral palsy, low birth weight, and severe intellectual disorder. http://www.ssa.gov/pubs/EN-05-10026.pdf