Prader-Willi syndrome is caused by what type of genetic change on chromosome 15?

Prader-Willi syndrome is primarily caused by a microdeletion on the paternal chromosome 15. This genetic change involves a loss of a small segment of DNA that affects the expression of certain genes that are critical for normal development and metabolism. The most common alteration identified in individuals with Prader-Willi syndrome is a deletion of the 15q11.2-q13 region, which can lead to the characteristic features of the disorder, including hypotonia, hyperphagia (excessive eating), obesity, intellectual disability, and behavioral problems.

While point mutations, duplications, and inversions can also lead to genetic disorders, they are not the mechanisms behind Prader-Willi syndrome. Point mutations often involve a single nucleotide change that can result in altered proteins, while duplications involve the repetition of sections of DNA and inversions refer to segments of DNA being flipped. In the case of Prader-Willi syndrome, the significant loss of genomic material due to a microdeletion is the key factor in the pathology of the syndrome.