Which genetic disorder is commonly associated with cognitive impairment and developmental delays due to an extra chromosome?

The genetic disorder commonly associated with cognitive impairment and developmental delays due to an extra chromosome is Down syndrome. This condition arises from an additional copy of chromosome 21, leading to the characteristics associated with the syndrome, including intellectual disabilities, distinct facial features, and various health issues. The presence of the extra chromosome impacts normal development and function, which is why individuals with Down syndrome frequently experience both cognitive challenges and developmental delays.

Down syndrome is specifically characterized by this genetic anomaly, making it distinguishable from other mentioned conditions. Marfan syndrome is primarily a connective tissue disorder affecting the skeletal and cardiovascular systems and does not inherently cause cognitive impairment. Turner syndrome results from a missing or partially missing X chromosome in females, affecting physical development rather than cognitive function. Angelman syndrome, while associated with developmental delays, is caused by a different genetic mechanism, specifically involving deletions or mutations on chromosome 15, rather than an extra chromosome. Therefore, Down syndrome is the only disorder in the list that matches the criteria of having an extra chromosome.