Prader-Willi Syndrome

Definition

Prader-Willi Syndrome is a genetic disorder that arises from the loss of function of specific genes on the paternal chromosome 15, leading to a variety of physical, mental, and behavioral issues. This syndrome is characterized by insatiable hunger, obesity, developmental delays, and emotional problems, connecting it to broader themes of genetic inheritance and genomic imprinting where gene expression is determined by the parent of origin.

5 Must Know Facts For Your Next Test

1. Prader-Willi Syndrome occurs due to the deletion or uniparental disomy affecting genes on chromosome 15 that are normally expressed only from the paternal allele.
2. Individuals with Prader-Willi Syndrome typically experience severe obesity due to uncontrollable hunger that begins in early childhood and persists throughout life.
3. The syndrome may also lead to hypogonadism, which can result in delayed puberty and infertility due to underdeveloped sexual organs.
4. Cognitive impairments are common in Prader-Willi Syndrome, with most individuals displaying mild to moderate intellectual disability and difficulties with executive functioning.
5. Behavioral issues such as temper outbursts, obsessive-compulsive tendencies, and social difficulties often accompany Prader-Willi Syndrome, making comprehensive care essential.

Review Questions

• How does genomic imprinting contribute to the manifestation of Prader-Willi Syndrome?
  • Genomic imprinting plays a key role in Prader-Willi Syndrome because the disorder is linked to the lack of expression of genes on the paternal chromosome 15. Normally, these genes are active only when inherited from the father. When there's a deletion or abnormality affecting this paternal allele, the associated features of Prader-Willi Syndrome emerge. This illustrates how parent-of-origin effects can significantly influence genetic disorders.
• Compare and contrast Prader-Willi Syndrome and Angelman Syndrome in terms of genetic origin and phenotypic presentation.
  • Prader-Willi Syndrome and Angelman Syndrome both involve abnormalities on chromosome 15 but differ in their genetic origin and clinical features. Prader-Willi results from loss of function of paternal genes, leading to symptoms like obesity and developmental delays. In contrast, Angelman Syndrome arises from maternal gene dysfunction, characterized by severe intellectual disability and movement disorders. Both conditions illustrate the significance of genomic imprinting in determining phenotype based on parental contribution.
• Evaluate the implications of hypothalamic dysfunction in individuals with Prader-Willi Syndrome and how it affects their quality of life.
  • Hypothalamic dysfunction in Prader-Willi Syndrome significantly impacts individuals' quality of life through its role in regulating hunger and energy balance. The hypothalamus fails to properly signal satiety, leading to an uncontrollable appetite that results in severe obesity. This not only raises health risks like diabetes and cardiovascular disease but also affects social interactions and emotional well-being. Understanding this dysfunction is crucial for developing effective management strategies to improve overall health outcomes for affected individuals.

Related terms

Genomic Imprinting: A genetic phenomenon where certain genes are expressed in a parent-of-origin-specific manner, affecting the phenotype depending on whether the allele is inherited from the mother or father.

Angelman Syndrome:

A neurogenetic disorder caused by the loss of function of genes on the maternal chromosome 15, presenting with severe intellectual disability, ataxia, and seizures, often used as a comparison to Prader-Willi Syndrome.

Hypothalamus: A region of the brain that regulates various bodily functions including hunger and energy expenditure; it plays a crucial role in the symptoms of Prader-Willi Syndrome related to appetite control.