The Genetic Disorder : Prader Willi Syndrome

Prader-Willi and Angelman Syndrome are two genetic disorders with vastly differing phenotypes linked by missing genetic imprints on the 15th chromosome’s q arm between regions 11 and 13 . While both orders result in mental deficits, their symptoms are otherwise segregated from the other in their entirety. The differences in the disorders are the result of differing DNA methylation patterns present in maternally and paternally inherited DNA. If the deletion occurs in the mother’s DNA, then Prader-Willi Syndrome appears. When the deletion occurs in the father’s DNA, Angelman Syndrome is the result.

This syndrome is from a mutation of a gene on chromosome 15 and this causes problems in the production of fibrillin-1 which is a protein that is an important part of connective tissue. The name for the gene is FBN1. Basically, it is the “glue” that helps to support the tissues in the human body. A child born to a parent with this syndrome has a 50% of having it. However, in the remaining 25%, neither parent has the disease which gives them a 1 in 10,000 chance of having a child with this disorder. When a child of two unaffected parents is born with it then the genetic mutation occurs in either the egg or sperm cell at the time of conception.

Miller-Dieker lissencephaly syndrome (MDS). MDS features include classic lissencephaly (incomplete or absent gyration of the cerebrum), craniofacial dysmorphims, mental retardation and intractable epilepsy. MDS is a life-shortening disease, with death most often occurring during early childhood (Dobyns, W.B., Curry, C.J.R., Hoyme, H.E., Turlington, L., and Ledbetter, D.H. Clinical and molecular diagnosis of Miller-Dieker syndrome. Am. J. Hum. Genet 1991. 48, 584–594; Nagamani, S.C., Zhang, F., Shchelochkov, O.A., Bi, W., Ou, Z., Scaglia, F., Probst, F.J., Shinawi, M., Eng, C., Hunter, J.V., et al. Microdeletions including YWHAE in the Miller-Dieker syndrome region on chromosome 17p13.3 result in facial dysmorphisms, growth restriction, and cognitive impairment.

Since it does not affect nutrition and meal absorption at all, it is presumed not to impair children’s growth, while it provokes consistent weight reduction (Velhote et al., 2007).

Williams Syndrome(WS) is considered as a neurodevelopmental disorder, caused by a contiguous gene deletion of about 26 genes from the long arm of chromosome 7(Peoples et al., 2000). Since it had been first aware by J.C.P. Williams in 1961(Lenhoff, Wang, Greenberg & Bellugi, 1997), Williams Syndrome has drawn more attention in last 40 years. the incidence rate is approximately 1 in 2000 and diagnosed generally at 6.4 years old (Morris, Demsey, Leonard, Dilts & Blackburn, 1988). People with WS usually show a developmental delay at the early age and are affected all life long. Williams Syndrome is characterised by some abnormalities in physical, behavioural, and cognitive.

While some inherited traits do not have significant effects on phenotypes, PPSH has a severe impact on physical appearance. The most significant effect on phenotype is the indistinguishable male genitalia. There have been three distinct phenotypic possibilities seen with PPSH in terms of sexual development. Some are born with ambiguous genitalia, which is difficult to determine the gender. Others have what appears to be male genitalia in the form of a micropenis while their urethra is on the other side of the penis. However, the most common phenotype in PPSH males is genitalia that appears female.

Prader-Willi Syndrome is rare with only 1 in 20,000 people born with the mutation. Normally offspring inherit one copy of

Smith-Magenis Syndrome (SMS) is a chromosomal disorder due to the deletion of genetic material on chromosome 17, more specifically 17p11.2 (PEDNEUR). It is estimated that SMS occurs in about 1 in every 25,000 births, affects boys and girls equally, and is underdiagnosed because there’s not as much awareness about it compared to other disorders and syndromes (PRISMS). Therefore, the prevalence may be 1 in every 15,000 births, and most of the people with SMS have been identified in the last 5 to 10 years due to improved cytogenetic testing (PEDNEUR). SMS was first discovered by Ann C.M. Smith a genetic counselor, and Dr. R. Ellen Magenis a physician and chromosome expert in 1986 (PEDNEUR).

The disorder affects 1 out of 40,000 newborns (Atlas Genetics). Almost 90% of patients with this disease have a parent with the disease, but the symptoms in the parent can be very different from the symptoms in the child (MedlinePlus). Waardenburg syndrome type 1 (WS1) and type 2 (WS2) are inherited as autosomal dominant traits, which means one copy of the altered gene in each cell is sufficient to cause Waardenburg syndrome (GHR). Manifestations of the disorder may not be present in individuals that inherit the altered gene for the disease. Some cases of the disorder, such as type 3 (WS3) and type 4 (WS4) have an autosomal recessive pattern of inheritance. Type 1 and type 2 of Waardenburg syndrome can also be acquired even when there is no family history of the disorder. The disorder can be caused from new genetic changes that occur spontaneously for unknown reasons. Researches indicate that new sporadic mutations for type 1 of Waardenburg syndrome may be associated with the advanced age of the father. In dominant disorders, a single copy of the gene with the disease that is either received from the mother of father will be expressed in the offspring by dominating the other normal gene, which causes the result in the appearance of the syndrome (Rare

Prader-Willi syndrome is a disorder that causes you to not feel satisfied with what you eat and not feeling full. This disorder affects many parts of the body. Prader -Willi syndrome is also very rare. Most people that have Prader – Willi syndrome then you most likely have type 2 diabetes. This is also a negative mutation.

In conclusion, genetic disorders mutate the DNA and in some cases, delete portions of it. Williams Syndrome is a genetic disorder that affects the genetic material on the seventh chromosome. The locus of 7q11.23 has over 25 genes deleted, which is why Williams Syndrome has so many implications and symptoms. Distinct facial features and facial structure characterize Williams Syndrome. It can also be marked by severe cardiovascular difficulties and other issues that make life quite difficult for the person suffering from this disorder. Williams Syndrome also affects the mental capacity and logical thinking of the brain. This implies that daily tasks and schoolwork can be greatly affected and require special care. Williams Syndrome is also considered

The deletion of chromosome 22 plays a crucial role in the development of a person. Since the major functions of the body are affected, daily life of someone diagnosed with DiGeorge syndrome has an underdeveloped reading and spelling comprehension. By the ause of low-average spelling and reading cognition, children with DGS have different learning environments in school. Children with this syndrome have to be put in special classes, because they learn on different, slower levels. On the severity of the disorder, some children have special courses and classes in school so they can reach their full potential. Daily life of someone diagnosed with DGS can vary on the criticalness of the disorder (Simon).

"Williams Syndrome - Genetics Home Reference." U.S. National Library of Medicine. National Institutes of Health, 212 Mar. 2017. Web. 21 Mar.

Another study states, PWS affects one out of every 10,000 births to 30,000 people globally and affects both males and females of all races and ethnicities (“What is Prader-Willi Syndrome, n.d.”). In addition, people with PWS have a loss of active genes in the region chromosome 15. Furthermore, USA Prader-Willi Syndrome Association (USAPWSA) explains, “In PWS, these critical genes are either missing (deleted) from the father’s chromosome 15, functioning improperly because of an imprinting defect, or the entire chromosome 15 from the father is missing and both chromosome 15s come from the mother.” This complication happens randomly, either during reproductive or embryo development. For instance, our family has no history of obesity or these other complications, yet my niece Janelle has a behavior issue, developmental disorders, and has been diagnosed obese as well as having diabetes type 2 this

40). This syndrome is an example of variable expressivity in that it varies from person to person depending on the size and pattern of the deletion in chromosome 7(Bartke & Siegmuller, 2004, p. 4r) . Facial deformity is a distinct phenotype of patients with Williams syndrome. These facial deformities consist of a flattened nasal bridge, ridges in the skin, and extra skin around the inner corners of the eye. Patients can also suffer from the following: dental abnormalities, attention deficit disorder, incoordination, poor calcitonin metabolism, microcephaly, kidney disease, and bladder disease (Bartke & Siegmuller, 2004, p. 4p-4q) (Williams syndrome, 2008). Learning and speaking disabilities are prevalent at varying degrees. However, there have been reported cases of Williams syndrome patients displaying outstanding intellectual and speaking abilities later in life. They are even known to excel in music (Williams syndrome, 2008). Although patients are known to have difficulties navigating through social cues, they are typically very friendly and trusting of