Angelman Syndrome Paper Sample

Introduction and prevalence

Angelman syndrome one of the genetic disorders that affect the nervous systems. The Angelman syndromes are characterized by delayed development, scoliosis, and ataxia. According to Sando, Angelman syndrome is also associated with intellectual impairment. Children with below the age of 10 with Angelman syndrome tend to have recurrent seizures and microcephaly. On the other hand, Napier et al argue that delayed envelopment in those children becomes noticeable as the child reaches 6 months and becomes pronounced in early childhood. Most of the children with Angelman syndromes have happy demeanors and can be mistaken to be happy even when they are sad. They appear excitable and smiling but they also exhibit hyperactivity and have a short attention span. The prevalence of Angelman syndrome is not properly documented because we most often misdiagnosed as cerebral palsy and or autism due to lack of knowledge and proper awareness. It is aware of genetic disorders as it is found in only 1 in 150000 live births. The disorders affected male and females equally but because many cases go undiagnosed, there is inaccuracy in the province of the disorder in the general population.

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Pathophysiology

The disorder is mainly assorted with the loss of the normal maternal contribution to chromosome 15 as a segment of the chromosome is deleted. According to Williams, Beaudet, Clayton-Smith, et al, "Angelman syndrome may also be caused by uniparental disomy, translocation or gene mutation in the region of chromosome 15" (413-418). Healthy children usually receive two copies of chromosome 15 from each of the parents. Never the less, in the people with Angelman syndromes, the sex-specific epigenetic imprinting leads to differential expression of some genes which is not the case in the normal individuals in whom the maternal allele of UBE3A is expressed while the paternal allele is inhibited or silenced in the brain. It is important to note that if the maternal contribution is mutated or deleted from the hippocampus and c cerebellum, the newborn would have the Angelman syndrome and not the Prader-Willi syndrome.

While the Angelman Syndrome is usually caused by a single mutation in the genes (UBE3A gene), the common genetic defect that usually results in Angelman syndrome is the 4mega base deletion in the 15q11-13 chromosome region that leads to the loss of the UBE3A expression. The ubiquity ligase is responsible for the selective selection of the substrate and is associated with the hippocampal memory function. The deficiency of the E3 ubiquitin-protein ligase gene expression leads to poor development of the gene. Therfi5e, if there is an abnormality in the UBE3A, the gene itself disappears, a change in the gene structures or total change in the function of the gene. Some of the most common genetic disorders include chrome deletion, imprint errors as well as paternal uniparental disomy. Deletion in the chromosomal region 15 arises due to the complicated chromosomal rearrangement. Defects in the genetic imprinting are also attributed to DNA methylation (Napier et al. 21).

Angelman's syndrome is a complex genetic disorder associated with the nervous system. The disorder has some distinct features like intellectual disability, delayed development, severe speech impairment as well as movement and balance problems. It is also common among the affected children to experience have recurrent seizures and a small size of the head. The measurement of one's development can be successfully evaluated between the ages of 6 to 12 months, during which many other signs of the disorder can be observed (Sato 5). The affected children tend to be happier and need relatively less sleep. The problem tends to grow worse as a victim of the disorder grows although one's lifespan remains almost normal.

The manifestation of the disorder is connected to the loss of the function of the gene UBE3A. It is introduced to a child when one inherits a copy of the gene from both parents. People normally inherit one copy of the UBE3A gene from each parent. The activation of the two copies in most body tissues marks the beginning of the disorder in some areas of the body. Napier et al. (27) argued that the situation is however unique for the case of the brain where certain areas recognize only the copies inherited from a mother, commonly known as the maternal copy which is active in this context. This shows that at some point, there exists a form of activation which is a parent-specific gene, and these results from a phenomenon referred to as genomic imprinting. It, therefore, follows that in case of the loss of the maternal copy of UBE3A as a result of gene mutation or chromosomal change a, an associated person may not have active copies in some parts of one's brain.

Diagnosis

A genetic test can reveal the underlying cause of the etiology. For example, conducting the DNA methylation test can help in determining the Parental DNA pattern and its role in the Angelmans disease. Secondly, chromosomal microarray test can be used to determine the missing chromosome while the gene mutation test can help in determining if the condition was caused by the mutation of the maternal copy of the UBE3A gene (Williams et al. 413-418). There are many genetic mechanisms which can delete or inactivate the maternal copy of the gene causing the disorder. The deletion of the gene has caused the greatest percentage of the cases of the Angelman syndrome. Showed that more than 70% of the occurrence of the disorder have been noticed when a portion of the chromosome 15 of the maternal type containing the gene is deleted. Other rare cases of Angelman syndrome approximately 11 percent, results when a mutation occurs in the maternal copy of the gene.

A few cases of the disorder have presented the occurrence of Angelman syndrome which results from the inheritance of two copies of the chromosome 15 of the paternal copies, which is from one's father, rather than obtaining one from each of his or her parent (Napier et al. 27). The resulting phenomenon is referred to as the paternal uniparental disomy. Angelman syndrome is rarely caused by translocation, which a risky form of chromosomal rearrangements only in rare cases that Angelman syndrome can occur as a result of mutation or any other defect in the DNA region that has control over the inactivateUBE3A or any other gene on the chromosome 15 maternal copy.

The disorder can occur however the cause may not be successful studied and known in many cases. A considerable percentage of the affected individuals ranging from 10 to 15 percent have remained unknown. This implies that the cause of the disorder is not obvious based on the probable failure to trace the causal phenomena concerning the Angelman syndrome (Pastuzyn & Jason 36). Other changes involving the other chromosomes or genes may be taken to be responsible for the disorder in such cases. This shows that as much the cause of the disorder is normally traced with the alteration of the associated gene, assumptions may be used to conclude that could be the reason behind the phenomena. The occurrence of the Angelman syndrome in some people occasionally leads to the loss of the gene known as OCA2. This phenomenon can be detected when an affected person experiences fair skin and light-colored hair. The gene is normally found on the chromosome 15 segment that is normally deactivated or deleted in those experiencing this disorder. It is, however, important to note that the loss of OCA2 gene is not necessarily the cause of the other indicators of Angelman syndrome. The gene produces a type of protein which can help in the determination of the coloring of the hair, skin, and eyes (Williams et al. 413-418).

The inheritance pattern of the disorder requires more attention for a better understanding of the possible cause of the Angelman syndrome. Many cases of the Angelman syndrome occur as a result of many different other conditions other than inheritance. For instance, the disorder is not associated with inheritance when Angelman syndrome results from the paternal uniparental disomy or deletion of the maternal chromosome 15. The changes are based on the arrangement of the genetic and occur as random phenomena during the formation of the reproductive cells like eggs and sperm. Such genetic changes also tend to occur during the early stages of the embryonic development. The affected people in this manner are not associated with any form of family history regarding the occurrence of the disorder. This is genetic changes responsible for Angelman syndrome cannot be easily inherited.

Treatment

Currently, there is no treatment for the Angelman syndrome. However, despite the several drugs trials, the current focus is on how to manage the unmet clinical needs associated with the condition. For example, movement disorders, communication impairment, behavioral problem and sleep problems are currently the most important problems that are given special consideration (Wheeler, Sacco and Cabo 93-104). It is also important to note that as the individual gets older, hyperactivity may resolve while movement disorders, aggression, anxiety may get worse. It is only advisable for care providers to ensure that the symptom-based therapies are maintained as the researchers look for treatments that can address the underlying etiology

Conclusion

With the low prevalence records, the Angelman syndrome lacks a standardized treatment protocol. Angelman syndrome is mainly caused by the disruption of the maternally imprinted UBE3A gene in the 15q11.2-q13 chromosome which leads to loss of UBE3A function. Pre-natal testing can be done to detect the underlying causes of the disorder is a deletion, UPD or UBE3A pathogenic variants or mutation of the maternal copy of the UBE3A gene. In very few cases, the Angelman syndrome can arise from translocation. Currently, there is no approved therapy apart from the symptom-based treatment which does not address the underlying cause of the diseases. While the severity of the disorder can be managed

References

Sato, Masaaki. "Early Origin And Evolution Of The Angelman Syndrome Ubiquitin Ligase Gene Ube3a." Frontiers in Cellular Neuroscience 11.21 (2017): 5. Web.

Pastuzyn, Elissa D., and Jason D. Shepherd. "Activity-Dependent Arc Expression And Homeostatic Synaptic Plasticity Are Altered In Neurons From A Mouse Model Of Angelman Syndrome". Frontiers In Molecular Neuroscience, vol 10, 2017. Frontiers Media SA, doi:10.3389/fnmol.2017.00234.

Napier, Kathryn R. et al. "A Web-Based, Patient Driven Registry For Angelman Syndrome: The Global Angelman Syndrome Registry." Orphanet Journal of Rare Diseases 12.1 (2017): n. pag. Web.

Williams A, Beaudet AL, Clayton-Smith J, et al. Angelman syndrome 2005: updated consensusfor diagnostic criteria. Am J Med Genet. 2006;140(5):413-418.6

Pastuzyn, Elissa D., and Jason D. Shepherd. "Activity-Dependent Arc Expression And Homeostatic Synaptic Plasticity Are Altered In Neurons From A Mouse Model Of Angelman Syndrome". Frontiers In Molecular Neuroscience, vol 10, 2017. Frontiers Media SA, doi:10.3389/fnmol.2017.00234.