For 10 points name this autosome, a trisomy of which causes Down Syndrome.
Rare conditions associated with this entity include a type of primordial dwarfism known as MOPD II which is linked to its PCNT region, as well as an inherited inability to use biotin properly, connected to its HLCS region. Isoleucine may replace valine in its amyloid beta (A4) precursor protein leading to early onset Alzheimer's disease, and an A4V mutation on its SOD1 gene is one cause of Lou Gehrig's disease. This was the second chromosome to be fully sequenced by the Human Genome Project, and it contains fewer (*) nucleotides than any other chromosome. Its long arm may be translocated in one cause of this chromosome's best known disorder whose symptoms include heart defects, upward slanting eyes, and flat facial features. For 10 points name this autosome, a trisomy of which causes Down Syndrome.
Rare conditions associated with this entity include a type of primordial dwarfism known as MOPD II which is linked to its PCNT region, as well as an inherited inability to use biotin properly, connected to its HLCS region.
chromosome 21