Hereditary mixed polyposis syndrome is caused by a 40-kb upstream duplication that leads to increased and ectopic expression of the BMP antagonist GREM1
Jaeger E., Leedham S., Lewis A., Segditsas S., Becker M., Cuadrado PR., Davis H., Kaur K., Heinimann K., Howarth K., East J., Taylor J., Thomas H., Tomlinson I.