prader-willi

Prader-Willi Syndrome (PWS) is a rare genetic disorder. It causes poor muscle tone, low levels of sex hormones and a constant feeling of hunger. The part of the brain that controls feelings of fullness or hunger does not work properly in people with PWS. They overeat, leading to obesity.

Babies with PWS are usually floppy, with poor muscle tone, and have trouble sucking. Boys may have undescended testicles. Later, other signs appear. These include:

• Short stature
• Poor motor skills
• Weight gain
• Underdeveloped sex organs
• Mild intellectual and learning disabilities

There is no cure for PWS. Growth hormone, exercise, and dietary supervision can help build muscle mass and control weight. Other treatments may include sex hormones and behavior therapy. Most people with PWS will need specialized care and supervision throughout their lives.

NIH: National Institute of Child Health and Human Development

Genes are the building blocks of heredity. They are passed from parent to child. They hold DNA, the instructions for making proteins. Proteins do most of the work in cells. They move molecules from one place to another, build structures, break down toxins, and do many other maintenance jobs.

Sometimes there is a mutation, a change in a gene or genes. The mutation changes the gene's instructions for making a protein, so the protein does not work properly or is missing entirely. This can cause a medical condition called a genetic disorder.

You can inherit a gene mutation from one or both parents. A mutation can also happen during your lifetime.

There are three types of genetic disorders:

• Single-gene disorders, where a mutation affects one gene. Sickle cell anemia is an example.
• Chromosomal disorders, where chromosomes (or parts of chromosomes) are missing or changed. Chromosomes are the structures that hold our genes. Down syndrome is a chromosomal disorder.
• Complex disorders, where there are mutations in two or more genes. Often your lifestyle and environment also play a role. Colon cancer is an example.

Genetic tests on blood and other tissue can identify genetic disorders.

NIH: National Library of Medicine