Paternal 15 chromosome deletion is seen in -

Prader-Willi syndrome (PWS) is a genetic disorder due to loss of function of specific genes. In newborns symptoms include weak muscles, poor feeding, and slow development. In childhood the person becomes constantly hungry which often leads to obesity and type 2 diabetes. There is also typically mild to moderate intellectual impairment and behavioral problems. Often the forehead is narrow, hands and feet small, height sho, skin light in color, and they are unable to have children. About 70% of cases occur when pa of the father's chromosome 15 is deleted. In another 25% of cases the person has two copies of chromosome 15 from their mother and none from their father. As pas of the chromosome from the mother are turned off they end up with no working copies of ceain genes. PWS is not generally inherited but instead the genetic changes happen during the formation of the egg, sperm, or in early development. There are no known risk factors. Those who have one child with PWS have less than a 1% chance of the next child being affected.] A similar mechanism occurs in Angelman syndrome except there is a defective chromosome 15 from the mother or two copies from the father. Prader-Willi syndrome has no cure. Treatment, however, may improve outcomes, especially if carried out early. In newborns feeding difficulties may be suppoed with feeding tubes. Strict food supervision is typically required staing around the age of three in combination with an exercise program. Growth hormone therapy also improves outcomes.