Prader-Willi Syndrome
Emily Moore
Psychology
Ms. Brown
October 14, 2009

Emily Moore
Brown
Psychology
October 14, 2009
Prader-Willi Syndrome After two years of trying, Mr. and Mrs. Jones are expecting their first child, a baby boy. Just a little short of nine months later, Joey Jones was brought into this world, crying, thriving, and most importantly, healthy. Overjoyed, they took their new baby home to begin their fresh, exciting life with little Joey. However, in the first few weeks, a problem arose, baby Joey was having a hard time latching on to his bottles at feeding time, so Mrs. Jones and Joey were off to the doctor. Reassured, the doctor told her it’s not uncommon and suggested a few different brands of bottle nipples to help alleviate the problem. Not but a few months later, Joey’s mom noticed not only was he still having a hard time latching onto a bottle but also, his motor skills didn’t seem to be developing like most 4 month olds, due to low muscle tone. However, his appetite was increasing by the day and he just always seemed to be hungry. Once again worried something was wrong with her precious baby boy, back to the doctor Mrs. Jones and little Joey went, but this time, Mr. Jones came too for support. Unfortunately, this time the doctors’ news wasn’t so good. They informed the Jones’ they wanted to test Joey, apprehensive that he was developing most of the signs of Prader-Willi Syndrome. Prader-Willi Syndrome is, “a genetic disorder characterized by short stature, mental retardation, hypotonia, abnormally small hands and feet, hypogonadism, and uncontrolled appetite leading to extreme obesity” (Medical dictionary). After the tests came back positive for little Joey the doctor explained that the Jones’ had a long road ahead of them. Though this disease is very uncommon much research has been done on it and the two common theories on how this disease occurs is, paternal deletion during genomic imprinting and maternal uniparental disomy. More than seventy percent of cases of Prader-Willi Syndrome occur because of paternal deletion during genomic imprinting. In this theory, the syndrome is not said to be inherited, but simply just happens. In this situation, chromosome 15, which is usually inherited by both parents, is missing the paternal region (the region coming from the father). This causes a loss in the genes in this specific region. At this time, the only gene they have determined is deleted and causes symptoms of Prader-Willi is the OCA2 gene which causes unusually fair skin, and light colored hair. This genetic change in each and every cell in the body results in a loss of gene function, which proves to be of dire importance in our gene makeup. Once again, since the deletion happens for no reason it is unlikely (less than 1%) chance of it happening again in another pregnancy (Genetics Home Reference). At this point, this theory, as well as all others of the Prader-Willi Syndrome, have no way of prevention only a way of detection. The second theory is found in a mere 25% of cases and is not too far off from the first theory just has more to do with the mother, its known as, Maternal uniparental disomy. Maternal means mother; uniparental translates to one parent; and disomy is deciphered as two chromosome bodies. In this circumstance, both copies of the chromosome are inherited from the mother, when in a healthy person they receive one from each. In these cases the developing fetus starts out with 3 copies of chromosome 15 due to an extra chromosome 15 in the mothers egg. Later, instead of the chromosome lost being the extra of the mothers, the one from the father is lost as a substitute. The