What Causes Down Syndrome Facial Features?
What Causes Down Syndrome Facial Features? The most common live-born human aneuploidy is trisomy 21, which causes Down syndrome (DS). Dosage imbalance of genes on chromosome 21 (Hsa21) affects complex gene-regulatory interactions and alters development to produce a wide range of phenotypes, including characteristic facial dysmorphology. What causes Down syndrome appearance? Down syndrome is a