Which syndrome is an example of an imprinting disorder?

Angelman syndrome is indeed an example of an imprinting disorder, which arises from the concept of genomic imprinting. This phenomenon occurs when certain genes are expressed in a parent-of-origin-specific manner. In the case of Angelman syndrome, which is typically caused by the loss of function of the UBE3A gene located on chromosome 15, the paternal allele is usually silenced while the maternal allele is expressed. If the maternal copy is deleted or mutated, it leads to the symptoms associated with Angelman syndrome, such as severe developmental delay, seizures, and problems with movement and balance.

In contrast, Turner syndrome, Klinefelter syndrome, and cystic fibrosis result from other genetic mechanisms and do not involve genomic imprinting. Turner syndrome is characterized by the absence of one X chromosome in females and is primarily associated with developmental issues and infertility. Klinefelter syndrome involves the presence of an extra X chromosome in males, which leads to features such as reduced testosterone levels and infertility. Cystic fibrosis is caused by mutations in the CFTR gene and is an autosomal recessive disorder, affecting the respiratory and digestive systems. Hence, the distinct mechanisms underlying these other conditions set them apart from imprinting disorders like Angelman syndrome.