Trisomy 8

Trisomy 8, also known as Warkany syndrome 2, is a chromosomal disorder caused by the presence of three copies of chromosome 8 in some or all of a person's cells rather than the usual two. A complete, non-mosaic form is usually lethal before birth, so most people living with the condition have the mosaic form, in which only a proportion of cells carry the extra chromosome. Those who survive into childhood and adulthood commonly show stunted psychomotor development, moderate to severe intellectual disability, growth patterns that can produce either unusually short or unusually tall stature, a relatively expressionless face, and a range of musculoskeletal, visceral and eye abnormalities. A deep furrow on the sole of the foot is considered a distinctive physical sign of the condition.